CYP1A1*2A polymorphism was significantly associated with increased lung cancer risk , whereas EPHX1 Tyr113His and SULT1A1 Arg213His conferred reduced risk . In smokers, EPHX1 Tyr113His and SULT1A1 Arg213His polymorphisms reduced the risk of lung cancer, whereas CYP1A1*2A, CYP1A1*2C and GSTP1 Ile105Val imparted increased risk in non-smokers only. While exploring non-linear interactions through CART analysis, smokers carrying the combination of EPHX1 113TC (Tyr/His), SULT1A1 213GG (Arg/Arg) or AA (His/His) and GSTM1 null genotypes showed the highest risk for lung cancer , whereas combined effect of CYP1A1*2A 6235CC or TC, SULT1A1 213GG (Arg/Arg) and betel quid chewing showed maximum risk in non-smokers . MDR analysis identified two distinct predictor models for the risk of lung cancer in smokers  and non-smokers  with testing balance accuracy (TBA) of 0.6436 and 0.6677 respectively. Interaction entropy interpretations of MDR results showed non-additive interactions of tobacco chewing with SULT1A1 Arg213His and EPHX1 Tyr113His in smokers and SULT1A1 Arg213His with GSTP1 Ile105Val and CYP1A1*2C in nonsmokers. These results identified distinct gene-gene and gene environment interactions in smokers and non-smokers, which confirms the importance of multifactorial interaction in risk assessment of lung cancer.Complex disease such as cancer results from interactions of multiple genetic and environmental factors. Studying these factors singularly cannot explain the underlying pathogenetic mechanism of the disease. Multi-analytical approach, including logistic regression (LR), classification and regression tree (CART) and multifactor dimensionality reduction (MDR), was applied in 188 lung cancer cases and 290 controls to explore high order interactions among xenobiotic metabolizing genes and environmental risk factors. Smoking was identified as the predominant risk factor by all three analytical approaches. Individually,  Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer death globally CYPs), alcohol dehydrogenase (ALDH) and epoxide hydroxylase (EPHX) usually activate the procarcinogens through oxidation and dehydrogenation thereby converting them into reactive metabolites. Phase II metabolic enzymes such as glutathione S-transferases (GST), sulfotransferase (SULT) and N-acetyltransferase (NAT) generally result in inactivation or detoxification of these reactive metabolites. Equilibrium between expression and activity levels of these xenobiotic-metabolizing enzymes of both phase I and II determine the relative level of detoxification of carcinogens. However, these pathways are also known to activate toxic and carcinogenic chemicals to electrophilic forms that react irreversibly with macromolecules such as proteins and nucleic acids leading to carcinogenesis.Individuals possessing modified ability to metabolize carcinogens such as polycyclic aromatic hydrocarbons (PAH), which are ubiquitous environmental, dietary, and tobacco carcinogens are at increased risk of developing cancer. Thus genetic variants in xenobiotic metabolizing genes can influence their clearance from circulation and determine response to such carcinogens. The phase I xenobiotic metabolizing enzymes like cytochrome P-450s (Single nucleotide polymorphisms (SNPs) in xenobiotic metabolizing genes have been studied extensively with risk of lung cancer. A majority of these molecular epidemiological studies consider only the main effects of these SNPs and their observed strength of associations could be challenged by penetrance of the genetic variant. Furthermore, a single locus cannot account for genetic susceptibility in a complex disease such as cancer which involves multiple genetic variations and gene-environment interactions. Current evidences suggest that high order interactions in multigenic approach allow more precise delineation of risk groups EPHX1 and CYP1A1 SNPs, we estimated their haplotype frequencies and risk imparted towards lung cancer.In the present study, two data mining approaches, CART and MDR were applied along with LR to detect high order gene-gene and gene environment interactions. Both CART and MDR assume model free and non-parametric methods of estimating non-linear interactions with low false-positives even on relatively small sample sizes. Model validation through permutation testing and false positive report probabilities were also done to overcome inaccurate estimation. Interaction entropy graphs were constructed to interpret combination effects identified by MDR. To further analyze possible effects of the This study consisted of 188 histopathologically diagnosed lung cancer cases registered at Dr. Bhubaneswar Borooah Cancer Institute, Guwahati, Civil Hospital, Aizawl, and Sir Thutob Namgyal Memorial Hospital, Gangtok, the collaborating centers in north east India. Incident cases during the period of December 2006 to 2009 and willing to participate in the study were included. 290 voluntary, age (±5 years) and sex matched individuals were selected from the unrelated attendants who accompanied cancer patients. This provided a readily available and cooperative source of controls from the same socio-economic background as the cases reducing confounding biases. As our collaborating centers were public hospitals a large majority of subjects belonged to lower to middle socio-economic background. Demographic data and characteristics such as age, sex, smoking habit, usage of tobacco, betel quid and alcohol, were obtained from subjects in a standard questionnaire used for all the centers, in an in-person interview by a trained data collector. A majority of cases and controls were literate with full primary schooling and some upto the college level. The occupational history of the study participants revealed that most of them were farm laborers or engaged in petty jobs and the nature of such jobs did not exposed them to any occupational hazards. Any history of past or present illness was enquired or if undergoing any medication at the time of enrolment. Patients with only lung as their primary site of cancer were included. Any subject with history of familial malignancy or pulmonary infectious disease was excluded both from case and control. Final selected controls were included on the basis of no history of any obvious disease and those not taking any medication at the time of recruitment. All subjects provided written informed consent for participation in this research which was done under a protocol approved by the institutional ethics committee of Regional Medical Research Centre, North East Region . Smokers, chewers and drinkers were classified into two categories ever and never. For smoking, an individual who had never smoked or smoked less than 100 cigarettes in their lifetime and were not smoking at the time of reporting was considered never smoker or non-smokers. Ever smokers or smokers category included current smokers, and those who had quit within <1 year of reporting GSTM1 and GSTT1 were determined by multiplex polymerase chain reaction protocol and SNPs in CYP1A1, EPHX1, GSTP1, SULT1A1 were determined by polymerase chain reaction–restriction fragment length polymorphism assays as previously described Genomic DNA was isolated using Qiagen Blood DNA Isolation kit  and stored at −30°C till further analysis. Details for SNPs selected for the study are summarized in 2) and Fisher's Exact test wherever appropriate. Hardy–Weinberg equilibrium (HWE) was assessed by using the χ2-test. Estimates of risk to cancer, imparted by genotypes and other covariates as tobacco smoking, tobacco chewing, betel quid chewing and alcohol consumption were determined by deriving the odds ratio (OR) and its corresponding 95% confidence interval (95% CIs) using multivariable conditional logistic regression. For all the tests a two sided p<0.05 was considered statistically significant. The data analysis was performed on the Intercooled Stata 8.0 statistical software package .Cases were individually matched with controls on the basis of age (±5 years), sex and ethnicity, in a ratio of approximately 1∶1.5. Difference in the distribution of demographic characteristics and genotype frequencies between cases and controls were evaluated using the Chi Square  between SNPs were calculated using Haploview software ver.4.1.High order interactions were determined using CART, MDR and interaction entropy graphs.A binary recursive partitioning method was used to produce a decision tree that identified specific combinations of contributing factors associated with lung cancer risk using the commercially available CART software  http://www.epistasis.org). We applied Tuned ReliefF (TuRF) filter algorithm to remove noisy SNPs and avoid overfitting of data. Best models for each locus were selected by repeating the analysis for up to 10 seeds and applying 10 folds cross validation each time. Statistical significance of the best models selected for each locus was determined using 1000 fold permutation testing. p-values hence obtained for TBA and cross validation consistency (CVC), were considered statistically significant at 0.05 levels.The MDR software was developed by Ritchie et. al. in 2001 −6 to 10−1) with an estimated statistical power to detect an OR of 1.5 and 2.0 and α level equal to the observed p-value. The FPRP cutoff point was stringently kept to 0.2.Reports of gene-environment interaction studies are often challenged by false positive discoveries especially when results are generated by multiple comparisons. To estimate the FPRP and to evaluate robustness of the findings from MDR analysis we used the Bayesian approach described by Wacholder et. al. Interaction graphs were built to visualize and interpret the results obtained from MDR using Orange machine learning software package EPHX1 Tyr113His and SULT1A1 Arg213His polymorphisms in cases did not follow HWE (p<0.001 and p = 0.004 respectively).The distribution of gender and ethnicity was similar for cases and controls. The frequency distribution of males and females were 77.1% and 22.9% in cases and 76.2% and 23.85 in controls respectively. Mean age of cases and controls was 60.41±10.58 (range 30–82 yrs) and 57.19±10.75 (range 32–85 yrs) respectively. The distribution of all SNPs in control was in agreement with HWE (p>0.05), however alleles of CYP1A1*2A, EPHX1 Tyr113His, SULT1A1 Arg213His and GSTT1 null polymorphism were significantly different in cases from controls . Main effects of genotypes in lung cancer susceptibility were evaluated using conditional multivariable logistic regression. Heterozygous genotype in CYP1A1*2A was associated with increased risk  whereas heterozygous genotypes in EPHX1 Tyr113His and SULT1A1 Arg213His imparted reduced risk towards lung cancer . CYP1A1*2A and EPHX1 His139Arg polymorphisms were associated with increased risk to lung cancer in dominant genetic model, whereas EPHX1 Tyr113His and SULT1A1 Arg213His imparted reduced risk in recessive genetic model . In EPHX1, the “TA” haplotype was the most common with frequencies of 44.79% and 45.04% in cases and controls respectively. No haplotype was found to be significantly associated with lung cancer risk.CYP1A1*2A polymorphism imparted significant risk in non-smokers . Also, CYP1A1*2C variant genotype and GSTP1 Ile105Val heterozygous genotype were significantly associated with increased risk in non-smokers . Heterozygous genotypes in EPHX1 Tyr113His and SULT1A1 Arg213His were associated with 66% and 55% reduced risk in smokers . However heterozygous genotype in EPHX1 His139Arg conferred significant risk in smokers .Since smoking is a well established risk factor to lung cancer and was the strongest independent risk factor in LR, we further stratified the data by smoking status. Distribution and risk associated with genetic factors after stratification is shown in EPHX1 Tyr113His, SULT1A1 Arg213His and GSTM1. In non-smokers first split was on CYP1A1*2A status, which was in concordance with the LR analysis where CYP1A1*2A showed strong association to risk only in nonsmokers. Further interactions were predicted by SULT1A1 Arg213His polymorphism and betel quid status. Terminal node 7, which comprised of least percentage of cases in non-smokers, was taken as reference to calculate OR for other terminal nodes. Among smokers maximum risk was observed for terminal node1 consisting of EPHX1 113TT (Tyr/Tyr) or -113CC (His/His) genotypes  and for terminal node 2 with combination of EPHX1 113TC (Tyr/His), SULT1A1 213GG (Arg/Arg) or AA (His/His) and GSTM1 null genotypes . In non-smokers high risk was seen for terminal node 5 comprising of CYP1A1*2A 6235CC or TC, SULT1A1 213GG (Arg/Arg) and betel quid chewing . Parallel to the above, CART analysis on separate data sets of smokers and non-smokers was also performed. However, we did not detect any high-order interaction in these analyses (data not shown).EPHX1 Tyr113His was most significant with CVC of 10/10 and TBA of 0.6407 (p<0.001). The 3 locus model consisted of smoking, EPHX1 Tyr113His and EPHX1 His139Arg with TBA of 0.6497 (p<0.001) and CVC of 10/10. The 4 loci interaction model of smoking, EPHX1 Tyr113His, EPHX1 His139Arg and SULT1A1 Arg213His, was the best model identified, with maximum CVC (10/10) and TBA . This model had a chi-square value of 66.31 (p<0.0001) and an OR of 4.93 (95%CI = 3.32−7.33). In smokers the best interaction model was the three loci model consisting of tobacco chewing, EPHX1 Tyr113His and SULT1A1 Arg213His having maximum CVC (10/10) and TBA  among all models identified. The model imparted 3.5 fold increased risk for lung cancer (95%CI = 2.69−7.69). In non-smokers the best model was the three loci model comprising of CYP1A1*2A, GSTP1 Ile105Val and SULT1A1 Arg213His with CVC of 10/10 and TBA of 0.6677 (p<0.005) and an OR of 7.32 (95%CI = 3.24−16.53).MDR analysis was applied to further explore gene-gene and gene-environment interactions. Best predictive models up to 4 orders of interaction, along with their CVC and TBA are summarized in −3 to 10−6) for detecting ORs of 1.5 and 2.0. However the best model selected in non smoker category showed true association only at high probability of 10−1 for detecting OR = 1.5 and till 10−2 for detecting OR = 2.0.EPHX1 Tyr113His had a large independent effect (4.64%) and a non-additive interaction with tobacco chewing (entropy 1.79%). Considerable entropy was associated with SULT1A1 Arg213His (1.88%) and its interaction with tobacco chewing further removed 1.49% of entropy from case-control group. However we did not detect any non-linear interaction between the two SNPs in the model. We found small percentages of the entropy in case–control status explained by alcohol consumption (0.56%) and tobacco chewing (0.70%) independently, but a large percentage of entropy explained by the interaction between these two environmental factors (2.47%). In non-smokers, CYP1A1*2A showed strongest main effect with entropy removal of 4.7%. GSTP1 Ile105Val too had a strong independent effect  and its interaction with SULT1A1 Arg213His further removed 3.02% of entropy. A strong synergistic interaction was observed between SULT1A1 Arg213His and CYP1A1*2C as the combination removed an additional 2.61% of the total entropy.After identifying the high-risk combinations using MDR approach, interaction entropy algorithm was applied to interpret relationship between the variables. Graphs were constructed on MDR results obtained from analysis on total data set  and on dThe present study used multiple analytical methods to first assess associations and then explore possible interactions of xenobiotic metabolizing genes with environmental factors in risk to lung cancer. The applied data mining approaches have the ability to search and identify interactions regardless of the significance of the main effects. The most significant finding of this study is the consistently identified gene-gene and gene environment interactions by all the three statistical approaches.EPHX1 Tyr113His and SULT1A1 Arg213His was consistently identified in smokers. Both EPHX1 Tyr113His and SULT1A1 Arg213His conferred reduced risk in smoker subset in LR. The two polymorphisms along with EPHX1 His139Arg formed the best predictor model in MDR analysis in smokers and also formed subsequent splits within smokers in CART. EPHX1 enzyme catabolizes epoxides from PAH into dihydrodiols, which involves generation of more reactive carcinogenic metabolites. Substitution of a variant His allele at codon 113 (EPHX1 Tyr113His) decreases the activity of this enzyme His113 (slow type) as compared to Tyr113 (fast type) which imparts increased lung caner risk His113 allele to be associated with a significantly reduced risk in smokers Tyr113 homozygous genotype. Sulphonation reaction of SULT1A1 is a detoxification reaction, however it also involves bioactivation of certain procarcinogens, including heterocyclic amines and PAHs to form carcinogen-DNA adduct SULT1A1 Arg213His and risk of cancer are inconsistent, from null association with risk of colorectal cancer His213 allele His213 allele Smoking is the primary etiological factor in lung cancer. The same was reflected in the present study as smoking showed strong association in LR, best one factor model in MDR and formed first split in CART. Interaction of CYP1A1*2A and GSTP1 Ile105Val were the most important polymorphisms identified for lung cancer development. The variant allele of both the polymorphisms conferred significant risk in the non smoking subgroup in LR analysis. Similarly, MDR 3 loci model of CYP1A1*2A, GSTP1 Ile105Val and SULT1A1Arg213His polymorphisms was the best predictor of risk in non-smokers. The CYP1A1 6235T>C MspI (CYP1A1*2A) polymorphism, is associated with higher enzymatic activity towards benzopyrene CYP1A1 polymorphisms and lung cancer have yielded equivocal results CYP1A1*2A variant allele with lung cancer, however after stratification by smoking the association remained confined to non-smokers only. Further, in a pooled analysis of 11 studies on CYP1A1*2C polymorphism in lung cancer, Le Marchand et al CYP1A1 polymorphism with smokers. Similar results were reported in colorectal cancer where heterozygous and variant genotypes of both CYP1A1*2A and CYP1A1*2C conferred risk in combinations with NAT2 only among non-smokers In vitro cDNA expression study suggests that GSTP1 with 105Val variant results in a protein with reduced enzyme activity GSTP1 in carcinogenesis can be determined by the kind of xenobiotic involved owing to its substrate specificity and affinity Among non-smokers GSTM1 null genotype in smokers and betel quid chewing in non-smokers. The results are quite plausible because both hold functional and biological significance. High risk for smoking related lung cancer has been reported in individuals deficient in GSTM1GSTM1 enzyme have approximately one-third of the risk for lung carcinoma than smokers without the enzyme GSTM1 null genotype and smoking in various cancers including esophageal Confirming to its exploratory nature, CART analysis identified two more risk factors, EPHX1 Tyr113His and SULT1A1 Arg213His in smokers and CYP1A1*2A and GSTP1 Ile105Val in non-smokers were evident. Further, synergistic interactions of SULT1A1 Arg213His with GSTP1 Ile105Val and with CYP1A1*2C were observed in non-smokers.A post-hoc analysis through entropy graph was done to visualize and interpret interaction models identified by MDR. The previously documented main effects of CYP1A1 and EPHX1 genes. CG haplotype in CYP1A1 was significantly associated with risk of lung cancer. Noteworthy were results in EPHX1, where frequency of haplotypes among cases was strikingly similar to report published in esophageal cancer from north India As haplotype are more efficient and informative than separate markers, haplotype association analysis was carried out in CYP1A1*2A polymorphism is evident only among non smokers in all the three methods. LR and CART analyses even showed a gene-dosage effect for the increased lung cancer risk with the increasing number of variant allele in the CYP1A1*2A polymorphism. As aforesaid, this finding provides support to previously published reports EPHX1 Tyr113His and SULT1A1 Arg213His polymorphisms exclusively among smokers. Their combined models confer risk to lung cancer however individually both act as protective factors in smokers only. These factors hold their importance as the SNPs are functionally and biologically relevant and have been implicated in the carcinogenesis process in previous studies on various cancersAlthough both MDR and CART validated LR results, yet they differed in identifying some unique interactions, reflecting different methods followed by each program. Both approaches provide a clear advantage over the traditional LR by identifying non-linear interactions among discrete genetic and environmental attributes. Significant findings of the study are summarized in 1/n) where n = 4 both in total and stratified analyses. Multiple testing in data mining approaches such as CART and MDR sometimes compromises upon the comparative power. When numerous null hypotheses are being tested yielding higher order interacting combinations the inference drawn from a single erroneous rejection is not an appropriate strategy, rather the proportion of erroneous rejection needs to be controlled. This is achieved by estimation of FPRP. These approaches utilize internal cross-validations and permutation testing of p-value reducing the chances of making type I errors. Both MDR and CART apply cross validation of data before selecting the best model however MDR also uses 1000 fold-permutation testing, to validate its results for minimizing the proportion of false-positives due to multiple testing. The cross validation (5–10 fold) dividing the whole data set into different sets of training and testing set prevents over-fitting and artificial accuracy improvement. Permutation test is considered the gold standard for accurate multiple testing correction. Controlling for false discovery rate (FDR) is a more realistic approach than as compared to concerns raised by the multiple hypothesis testing. This is because FDR is the proportion of incorrect rejection among all such rejections. Likewise, the best models derived from MDR on total data set and smokers set in this study showed good reliability as associations remained robust even at low prior probabilities for FPRP testing. CART analysis was able to define genetic associations with fairly good measures. Correct classification of cases and controls in test data set was approximately 63% for both.Major challenge for the identification of true genetic and interactive effects in a multi-factorial study is simultaneous testing of several hypotheses. The three methods of analysis used in this study address the same research hypotheses but differ in terms of their statistical methodologies and analytical approaches. P-value adjustment for multiple testing was performed through SIDAK correction in LR model with the equality as (1-(1-α)GSTs with lung cancer EPHX1 Tyr113His and SULT1A1 Arg213His in cases showed deviation from HWE. After ruling out false positive associations and genotyping errors perhaps population stratification, could be a reason for this deviation. However, the cases were incident, and thus, the data do not show report or recall bias. Also case-control matching was done in reference to age, gender, and ethnicity, thereby controlling for any confounding effect accounted by these variables.There might be some limitations to this study. The sample size of our study was relatively small, however based on the evidences (OR) provided by our research group on association between In conclusion this study highlights that better predictors for lung cancer risk can be obtained through polygenic approaches and exploring gene-environment interactions. The study identified distinct patterns of interaction in smoking and non smoking sub groups. However, the results presented should be treated with caution since this is the first epidemiological evidence identifying the complex relationship between genetic polymorphisms and cancer susceptibility in the studied population. Further studies with large samples in independent populations are warranted to validate the findings of this study.Figure S1Interaction entropy graphs . The interaction model describes the percentage of the entropy (information gain) removed by each variable (main effect: represented by nodes) and by each pairwise combination of attributes (interaction effect: represented by connections). Attributes are selected on the basis of MDR results obtained in case of total data set. Labels: Smk: smoking, SULT: SULT1A1 Arg213His, Ex3: EPHX1 Tyr113His (EH3), Ex4: EPHX1 His139Arg, SULT.(TIFF)Click here for additional data file.Figure S2Summarized results for LR, MDR and CART analyses. Green boxes indicate OR<1. Red boxes indicate OR>1. For MDR and CART significant interactions are shown. LR results should be read individually. Alcohol was excluded as it did not appear significant in any analysis.(TIF)Click here for additional data file.Table S1Detailed list of xenobiotic genes and polymorphisms analyzed in the study. *Chromosomal position is based on NCBI Build 36.2 . ** Base pair #mentioned in text as CYP1A1*2A##mentioned in text as CYP1A1*2C$Not Applicable †internal control for GSTM1 and GSTT1 multiplex.(DOC)Click here for additional data file.Table S2Genotype representation and associations under dominant and recessive model between cases and controls.*crude odds ratio **odds ratio adjusted for smoking, tobacco chewing, betel quid chewing and alcohol.(DOC)Click here for additional data file.


MC4R) gene were associated with increased risk of obesity. Subsequently studies among different ethnic populations have shown mixed results with some confirming and others showing inconsistent results, especially among East Asians and Africans. We performed a comprehensive meta-analysis of various studies from different ethnic populations to assess the association of the MC4R polymorphism with obesity risk.Genome-wide association studies on Europeans have shown that two polymorphisms  near the melanocortin 4 receptor  with 95% confidence interval (CI) was calculated using fixed- or random-effects model.p<0.001). Similar trends were observed among subgroups of Europeans and East Asians, adults and children, studies with high quality score, and for each five MC4R polymorphisms independently.A total of 61 studies  for rs17782313 polymorphism (or proxy) were included in the meta-analysis. The results suggested that rs17782313 polymorphism was significantly associated with obesity risk (OR = 1.18, 95%CI = 1.15–1.21, MC4R polymorphism with risk of obesity. Further studies should be conducted to identify the causal variant and the underlying mechanisms of the identified association.The present meta-analysis confirms the significant association of  Obesity is a major health issue worldwide FTO) gene was identified as the first gene for common obesity by the genome-wide association study (GWAS) FTO with obesity has been further replicated in other independent populations MC4R) gene was reported as the second association signal for common obesity by the GWAS MC4R gene was found to be associated with obesity among both European adults  and children  MC4R gene was also suggested to increase the risk of obesity among Europeans  Obesity is a complex disease resulting from genetic and environmental factors, and their interaction MC4R gene and obesity risk across different ethnic populations.Meta-analysis is a useful statistical tool to pool data from individual studies, thereby increasing the statistical power and the precision of effect estimates. In this study, we only focused on obesity rather than the underlying quantitative traits (body mass index (BMI) etc.) since the data provided by the original publications were not uniform . Then, we performed a meta-analysis to assess the association between rs17782313 polymorphism near the MC4R and its association with obesity was firstly reported in 2008. The search strategy to identify all possible studies involved the use of the following key words: (melanocortin 4 receptor or MC4R) and (polymorphism or variant or variation) and obesity. The publication language was restricted to English. The reference lists of retrieved articles were hand-searched. If more than one article were published using the same case series, only the study with largest sample size was included. The literature search was updated on August 1, 2012.We searched the PubMed and Embase databases from 2008 to 2012 since rs17782313 polymorphism in MC4R polymorphisms  with obesity; (2) uses case-control or cohort design; and (3) provides OR with 95%CI under an additive model or sufficient data for calculation of these estimates. The following information was extracted from each study: (1) name of the first author; (2) year of publication; (3) country of origin; (4) ethnicity of studied population; (5) number of cases and controls; (6) OR with 95%CI under an additive model; (7) covariates adjustment; and (8) BMI criteria for obese cases and controls. Two authors independently assessed the articles for compliance with the inclusion/exclusion criteria, resolved disagreements through discussion and reached a consistent decision.A study was included in the meta-analysis only if it met all the following inclusion criteria: (1) it evaluates the association of any of the MC4R polymorphism with obesity was estimated by calculating pooled ORs and 95% CIs under an additive model as well as under dominant, recessive and allelic models. The significance of ORs was determined by Z test . Q test was performed to test the between-study heterogeneity. A random- (DerSimonian-Laird method p< = 0.10) or absence (p>0.10) of heterogeneity, respectively. The included studies were scored based on the criteria selected from published recommendations on the evaluation of the quality of genetic association studies p<0.05 was considered statistically significant). To evaluate the stability of the results, sensitivity analysis was performed by removing one study at a time. Data analysis was performed using STATA version 11 .The association of MC4R gene polymorphism and type 2 diabetes, metabolic syndrome, stroke, polycystic ovary syndrome, or cancer; 4 articles were excluded because they investigated the association between MC4R gene polymorphism and dietary intake; 11 articles were excluded as they assessed the associations between other polymorphisms (e.g. V103I (rs2229616) or I251L (rs52820871), which is not in LD with rs17782313 or rs12970134) and obesity; 19 articles were excluded since they investigated the association between MC4R gene variants and obesity-related traits, e.g. BMI, waist circumference, waist-to-hip ratio and fat mass percentage; one article was excluded because it included obese subjects also afflicted with polycystic ovary syndrome. Finally, 31 articles met all the primary inclusion criteria. However, two articles were further excluded because they were family-based The literature search identified a total of 197 potential relevant articles. Of these, 113 were excluded after reading the title or abstract because of obvious irrelevance. In addition, 7 articles were excluded since they were reviews; one article was excluded because it examined gene-environment interaction; 10 articles were excluded as they assessed the association between 2 = 0.82 in CEU); D′ = 0.902, r2 = 0.813 in CHB; D′ = 0.911, r2 = 0.662 in JPT, with rs571312 , with rs17700144 , with rs4450508 . In addition, for the overall meta-analysis, if one study contained more than one polymorphism, only one polymorphism was selected  for rs17782313 polymorphism p<0.001; I2 = 54.8%, p<0.001). In the stratified subgroups by ethnicity, the effect sizes were significant among both Europeans  and East Asians , but not among Africans . In addition, there was significant association among both in adults  and in children . The significant association of rs17782313 (or its proxy) with obesity risk remained even on restricting the analysis to studies with high quality . Furthermore, we also performed a subgroup analysis based on different polymorphisms. The results showed that all five polymorphisms were significantly associated with obesity risk   was significantly associated with obesity risk under an additive model  .I2 = 58.4%, p for heterogeneity = 0.004, p for heterogeneity = 0.001, p for heterogeneity<0.001, We also observed significant association of rs17782313 variant (or its proxy) under a dominant model , a dominant model (p = 0.200), a recessive model (p = 0.300), and an allelic model (p = 0.360).Sensitivity analysis was performed by excluding one study at a time. The results confirmed the significant association between rs17782313 polymorphism and obesity risk irrespective of the genetic model used for association analysis ,S4,S5,S6MC4R polymorphism and susceptibility to obesity across different ethnic populations. The results established that rs17782313 polymorphism near MC4R was significantly associated with the increased risk of obesity and similar trends were found among subgroups of Europeans and East Asians, adults and children, studies with high quality, and for each of the five polymorphisms investigated .To our knowledge, this is the first meta-analysis investigating the association between MC4R mutations in the development of extreme and early-onset obesity, recent publications have identified several common genetic polymorphisms near the MC4R gene contributing to the common obesity Although previous studies have reported several rare Meta-analysis of genetic association studies is usually fraught with the problem of heterogeneity between them It is possible that the effect sizes of genetic factors predisposing to human diseases are different across various ethnic populations MC4R polymorphism on obesity in children in this meta-analysis  was similar with the initial observation in European children  The effect size of common FTO gene, MC4R gene is highly expressed in the central nervous system which regulates the energy metabolism MC4R gene play important roles in the modulation of food intake and choice, but not energy expenditure MC4R polymorphisms increase obesity susceptibility.The MC4R is a 332-amino acid protein encoded by a single exon on chromosome 18q22. Evidences have suggested that like MC4R variants on risk of obesity. Further studies are required to replicate the association in Africans. Third, the effect of MC4R polymorphism on obesity related traits  were not assessed in the meta-analysis since the data provided by the original publications were not uniform, i.e., several studies provided mean and standard deviation (or 95%CI) across each genotype, while other studies provided beta and 95% CI, which impeded the further data analysis. Indeed, the initial GWAS with ∼14,000 subjects (Indian Asians and Europeans) MC4R polymorphism and BMI, although the association with obesity risk were not addressed among these three GWAS.The current meta-analysis has two strengths. First, we used the OR with 95%CI (under an additive model) after covariate adjustment from individual study to calculate the pooled OR, which increased the accuracy of effect estimate. Second, more than 300,000 subjects were included in the meta-analysis, which greatly improved the statistical power. However, several limitations should also be noted. First, different studies used different cut-offs for obesity, which may influence the overall result. However, within each specific ethnic group , the cut-offs were similar. We tried to overcome this shortcoming by performing subgroup analysis by ethnicity, which then indirectly considered the differences of obesity criteria. Second, there was only 1 study in subjects of African ancestry (African Americans), which did not show any effect of MC4R gene with susceptibility to common obesity. Further studies should be conducted to identify the causal variant and the underlying mechanisms of the identified association.This large meta-analysis confirmed the significant association of rs17782313 polymorphism near the Table S1Details of reasons for exclusion of studies from meta-analysis.(DOC)Click here for additional data file.Table S2Characteristics of studies included in the meta-analysis.(DOC)Click here for additional data file.Table S3Sensitivity analysis under an additive model.(DOC)Click here for additional data file.Table S4Sensitivity analysis under a dominant model.(DOC)Click here for additional data file.Table S5Sensitivity analysis under a recessive model.(DOC)Click here for additional data file.Table S6Sensitivity analysis under an allelic model.(DOC)Click here for additional data file.Figure S1MC4R gene and obesity risk under a dominant genetic mod.Meta-analysis of the association between rs17782313 polymorphism (or proxy) near the (TIF)Click here for additional data file.Figure S2MC4R gene and obesity risk under a recessive genetic model.Meta-analysis of the association between rs17782313 polymorphism (or proxy) near the (TIF)Click here for additional data file.Figure S3MC4R gene and obesity risk under a allelic genetic model.Meta-analysis of the association between rs17782313 polymorphism (or proxy) near the (TIF)Click here for additional data file.


Studies have reported an impact of central obesity on people’s health. The literature is scarce on the effects of waist circumference (WC) on pulmonary function. Our objective was to review the literature on the association between WC and pulmonary function.A systematic review was carried out in the PubMed, CINAHL, Web of Science and Scopus databases. The search included published, in press and online documents up to December 2011. A meta-analysis was carried out to obtain the pooled effect, and a meta-regression was performed to evaluate sources of heterogeneity.1 β = −15.9 ; forced vital capacity (FVC) β = −16.6 ) compared with women ; FVC β = −7.0 ). The meta-regression identified sex as the characteristic that most contributed to the heterogeneity (R2 = 54.8% for FEV1 and R2 = 85.7% for FVC).From the 547 studies identified, 10 were included. The meta-analysis revealed an inverse relationship between WC and pulmonary function parameters, indicating that the effect was greater among men (forced expiratory volume in 1 second (FEVThere seems to be an inverse relationship between WC and pulmonary function, mainly in men. More population-based studies should be performed, especially among children and adolescents, to confirm these findings. Our lifestyle has changed in the past decades. Nowadays many of us have adopted unhealthy habits that may impair our health. The gloThe wide use of body mass index (BMI) as an obesity measure is explained by its simplicity, but it does not provide information on body fat distribution,6. Studi1) and forced vital capacity (FVC)[The effects of obesity on pulmonary function parameters are influenced by the amount and distribution of body fat-14. Studty (FVC),9. The aty (FVC). Obesityty (FVC), as the ty (FVC). Besidesty (FVC).A review study on physiology of obesity and its effects on pulmonary function showed that central obesity is more likely to affect pulmonary volumes, without direct effects on pulmonary obstruction. The aimA systematic review was carried out using independent keywords in the following electronic databases: PubMed, Web of Science, Scopus and CINAHL. The use of independent keywords allows a broader search as it rules out potential mistyping and other errors when using Mesh Terms  in different databases. The keywords used were:  AND . In the Web of Science database, we needed to include ‘TS=’ before the parentheses for each subset of terms. The search was carried out on 1 January 2012 including all papers published until the end of 2011, with no data limits.To be included in the review, papers should be based on population-based observational  studies and should report the association between WC and pulmonary function parameters. Studies among specific groups (twins or people affected by a specific illness) were not included. Studies reporting only the peak expiratory flow rate assessed by peak flow and not by spirometer and that did not use linear regression during analysis were excluded from the present review.All references were imported into Endnote software . One of the authors (FCW) later read the titles and excluded those that did not report the outcomes of interest. Two authors (FCW and LCM) then read all abstracts independently. All disagreements with respect to inclusion/exclusion of papers were judged by a third author (JM-M). Independent reading of full texts was again done by two reviewers (FCW and LCM), while a third reviewer was used when disagreements happened. Information from papers was retrieved by two independent referees (FCW and LCM) and occasional disagreements were decided by the third reviewer (JM-M). After this stage, the list with all references from the selected papers was examined to look for other references that have not yet been included.Characteristics of studies, such as sample size, design, country, WC and pulmonary function measurement procedures, were extracted from papers. We also extracted linear regression coefficients (β) and dispersion measures ). The data extraction was carried out by two independent reviewers (FCW and LCM) and divergences were solved by consensus.All papers were classified according to an adaptation of the Downs and Black checklist. From thEach item scored one point, except for Item 4 that could result in 0 (no), 1  and 2 (yes). The scoring could therefore range from 0 to 18 points. Papers were categorized as: high chance of bias (0 to 5 points), average chance of bias (6 to 11 points) and low chance of bias (12 to 18 points). Papers were scored independently by two referees and occasional disagreements were decided by the third reviewer.1 and FVC. To obtain the pooled effect, a random model[I2 >90%) and possible differences in the measurement of WC. Only studies that measured the association between WC as a continuous variable with absolute values for FEV1 and FVC were included. As linear regression was used in all studies, those presenting results in liters were changed into milliliters. When the results of the study were not in accordance with such demands , the authors were contacted by email (three attempts) to obtain information to enable inclusion of the study in the meta-analysis. Two out of four authors replied.A meta-analysis was carried out with data on FEVom model was empl1 and FVC, which were in quintiles, were changed into centimeters, dividing each quintile by its respective increments (6.3 cm in men and 6.9 cm in women), because according to the author the relationship was linear. The only study among children and adolescents[For meta-analysis purposes, we pooled the regression coefficients (β) of the association investigated. During meta-analysis, studies presenting results stratified by sex were included twice, as independent analysis. After contact with the correspondence author of one study, the regA total of 547 references were retrieved: 101 from PubMed, 64 from Web of Science, 35 from CINAHL and 347 from Scopus. From these 547 references, 182 were duplicated – leaving 365 titles to be read. After the selection stages, 10 papers were included in the review. All stages of reference selection, and numbers of papers included/excluded are displayed on the flow chart  in men and 53.2 ml  in women[1 for men or women[1.FEVlescents, present; FVC β = −16.6 ) presented larger magnitude compared with that in women ; FVC β = −7.0 ). The FEV1/FVC relation was not used in the meta-analysis due to the very low number of studies showing these results (only three out of five studies met the inclusion criteria).The meta-analysis was carried out with FEV1 and 85.7% for FVC. Other tested variables were not important to lower the heterogeneity of the results during meta-analysis  and evaluated adults (18 years or older). In addition, only one study was carried out in a developing country, indicat1 and FVC in children and adolescents could not be assessed in the present review because only one Canadian study evaluated this age group[1 and FVC) was observed in this study, possibly due to the growth process that occurs during adolescence, as WC is considered an indication of body size, consequently influencing pulmonary volumes in children and adolescents.The prevalence of obesity and body shapes may differ between developed and poorer countries. The study by Ford and colleagues points out an increase in abdominal obesity, measured by WC, in the USA, while oge group. In contKlein and colleagues attempted to establish a geometrical relationship between weight, BMI and WC (considered as the circumference of a cylinder). WC mirrn = 98). All four methods were highly correlated (r >0.99) in men and women. They also provided reliable information on the trunk fat percentage, especially in women (R2 >0.65 in women and R2 <0.45 in men). Klein and colleagues thus discuss that there is no best site for measuring the WC[1 or FVC regardless of the measuring method to obtain the WC.Owing to discrepancy in measuring the WC, Wang and colleagues carried out a study in the USA to establish which WC measuring method was the most accurate to predict abdominal fat. The resg the WC. In this1 and FVC[Obese people, especially those with severe obesity, have higher metabolic demands and also increased respiratory demands. Much ha and FVC,13,28. T and FVC,12.The excess of fat in the abdomen and thoracic region may lead to decreases in the compliance and resistance of respiratory system, increasing energetic demands of breathing. MeasuriThe intention to run the analysis stratified according to potential heterogeneity sources was only workable for sex as other variables were not present in most studies, resulting in very few studies to be analyzed. The meta-analysis is very difficult to perform because not all studies present the same units to measure both WC  or pulmonary function parameters .I2 value in the meta-analysis, intrinsic factors to the study and some associated with the country where the research was carried out were assessed by the meta-regression. Heterogeneity was better explained by sex: R2 = 54.8% for men and R2 = 85.7 for women. It is known that the main determinants of pulmonary function are age, height and sex[During the evaluation of the high heterogeneity in our findings, indicated by the high  and sex. Another and sex.As a consequence, perhaps, the effect of WC on pulmonary function in men tends to be larger than that in women. The Human Development Index explained 10.2% of heterogeneity of the results. One plausible explanation is that the Human Development Index and physical activity are positively correlated, and phy1 and FVC in people older than 18 years, but it does not affect the relation between the two parameters. We also identified that the effect of WC on pulmonary function parameters was greater among men compared with women. Central obesity is possibly associated with restrictive patterns, but not airways obstruction; however, it cannot be entirely ruled out. Longitudinal studies, especially among children and adolescents, are needed to verify the effects in these age groups, as well as the long-term effects of WC on pulmonary function.Increases in WC result in decreased pulmonary function parameters, such as FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; WC: waist circumference.BMI: body mass index; CI: confidence interval; CINAHL: Cumulative Index to Nursing and Allied Health Literature; FEVThe authors declare that they have no competing interests.FCW had the idea for the study, reviewed all papers included in the review, performed the meta-analysis and drafted the manuscript. AMBM participated in the design of the study and contributed to the writing of the manuscript. LCM and JM-M reviewed the papers included in this review and helped in the data analysis. MRD and BLH helped with the meta-analysis and critically reviewed the manuscript. All authors read and approved the final manuscript.PRISMA 2009 flow diagram.Click here for file


DHFR 19 bp deletion, MTHFD1 1958G>A, MTHFR 1298A>C, MTHFR 677C>T, and SLC19A1 80A>G. In addition to looking at genotypes individually, we determined the number of genotypes associated with decreased folate metabolism in each relative (“risk genotypes”) and compared the distribution of these genotypes in maternal vs. paternal relatives. Overall, maternal relatives had a higher number of genotypes associated with lower folate metabolism than paternal relatives (p = 0.017). We expected that relatives would share the same risk genotype as the individuals with NTDs and/or their mothers. However, we observed that maternal relatives had an over-abundance of any risk genotype, rather than one specific genotype. The observed genetic effects suggest an epigenetic mechanism in which decreased folate metabolism results in epigenetic alterations related to the increased rate of NTDs and other birth defects seen in the maternal lineage. Future studies on the etiology of NTDs and other birth defects could benefit from including multigenerational extended families, in order to explore potential epigenetic mechanisms.Periconceptional folic acid use can often prevent neural tube defects (NTDs). Variants of genes involved in folate metabolism in mothers and children have been associated with occurrence of NTDs. We identified Irish families with individuals affected by neural tube defects. In these families, we observed that neural tube defects and birth defects overall occurred at a higher rate in the maternal lineage compared with the paternal lineage. The goal of this study was to look for evidence for genetic effects that could explain the discrepancy in the occurrence of these birth defects in the maternal vs. paternal lineage. We genotyped blood samples from 322 individuals from NTD-affected Irish families, identified through their membership in spina bifida associations. We looked for differences in distribution in maternal vs. paternal lineages of five genetic polymorphisms: the  Neural tube defects (NTDs) are congenital anomalies of the brain and spinal cord that cause significant morbidity and mortality  plays an important role in folate metabolism. The 677 T allele results in reduced enzyme activity and decreased folate metabolism  acts in folate metabolism and DNA synthesis, and the 1958G>A variant results in decreased enzyme stability  also acts in folate metabolism. Studies have yielded conflicting results on the effect of the 19 bp deletion at intron 1 on red blood cell folate concentrations  or a blood relative of the affected individual. In terms of relationship, relatives  had to be one of the following: parents, siblings, nieces, nephews, offspring , grandparents, uncles, aunts, first cousins and first cousins once removed (the offspring of the first cousins).Family members were interviewed in phases. Phase I evaluated pregnancy histories and the health of siblings in the original nuclear families (1995–2002). Phase II subjects  were identified by their siblings during Phase I and interviewed between 2000 and 2002. Phase III consisted of interviews with first cousins of the affected individuals (the children of the uncles and aunts) between 2002 and 2009. Between 2005 and 2006, affected individuals and their siblings were interviewed.For the present study, conducted in 2007, the response rate among eligible, locatable relatives was 49.5%, or 331 participants. From these, 322 gave a blood sample. Of these with a blood sample, 34 were relatives in families in which the individual with an NTD had anencephaly, 41 in which the affected individual had spina bifida occulta, 240 in which the affected individual had open spina bifida and 7 in which the affected individual had encephalocele.This study was conducted according to the guidelines from the Declaration of Helsinki and all procedures involving human subjects were approved by the Ethics Board of the Boyne Research Institute and the Ethics Committee of the Health Service Executive of the Irish Government's Department of Health and Children. Written informed consent was obtained from all subjects.©, and statistical analysis was conducted using SAS 9.1 , STATA©, and IBM® SPSS® v19. Measures of association were evaluated with t-tests for continuous variables and chi-square and Fisher's exact tests for categorical variables, with the level of statistical significance set at 0.05. First-degree relatives were parents, siblings, and children; second-degree relatives were aunts, uncle, nieces, nephews, and grandparents; and third-degree and higher relatives were cousins and first cousins once removed. Genotypes were analyzed using an additive model, consistent with previous studies. For logistic regression analyses, genotypes were dichotomized using a recessive model, consistent with previous studies. For each individual, we calculated the number of “risk genotypes” present. “Risk genotypes” were those associated with lower folate metabolism in previous studies .Data were managed using Microsoft EXCELDHFR 19 bp deletion (rs70991108), MTHFD1 1958G>A (rs2236225), MTHFR 1298A>C (rs1801131), MTHFR 677C>T (rs1801133), and SLC19A1 80A>G (rs1051266). PCR and pyrosequencing primers  as previously described . Quantitation was performed by spectrophotometric reading at 260nm and all samples normalized to 10 ng/μl. For PCR reactions, 2 μl genomic DNA (20 ng) was used. Pyrosequencing technology  was used to genotype DNA samples for Five percent of the samples were selected at random for repeat testing of the five polymorphisms, and the concordance was checked. We also tested each variant for any significant departure from Hardy-Weinberg equilibrium (HWE) by a chi-square goodness-of-fit test to verify data quality. In addition, Mendelian inheritance for all variants was assessed in 13 families with full trios using the PedCheck program , offspring (N = 2), fathers (N = 29), mothers (N = 37), siblings (N = 59), nieces and nephews (N = 2), uncles and aunts (N = 66), first cousins (N = 105), and grandparents (N = 2) from 47 families. Paternal relatives (N = 65) and maternal relatives (N = 115) comprised uncles and aunts, first cousins, first cousins once removed, and grandparents, who were related to the affected individual through the father and mother, respectively. The average age of the study participants was 41 years. The overall distribution of each of the five polymorphisms is shown in Table We obtained blood samples from all categories of relatives, including individuals with NTDs  than in all other relatives (42.7%)   had the higher folate-metabolizing AA genotype compared with second-degree (50.0%) relatives and third-degree and higher (53.6%) relatives (p = 0.009). Similarly, the A allele was less common in first-degree relatives (61.4%) than in second-degree relatives (70.0%) and third-degree and higher (73.7%) relatives (p = 0.005). When the genotype  and relatives  were dichotomized, the odds ratio for the association of the AA genotype with first-degree relatives was 0.49  (data not shown). Consistent with this, a lower percentage of siblings, 30.5%, had the AA genotype compared to 48.3% among other relatives    (Table p = 0.004).While the frequencies of individual genotypes did not differ significantly between maternal and paternal relatives Table , the num2) Table . A lowerp = 0.004) or mothers alone (p = 0.005), compared with all other relatives were also statistically significant , which are associated with NTD risk, might affect proper imprinting and establishment or maintenance of other epigenetic changes. These epigenetic effects could occur in the maternal genome and would have been initiated when the mother was a fetus herself, but may also have taken place in the genomes of the mother's parents  among distant relatives to allow for heritability testing, and inadequate number of samples from grandparents to evaluate epigenetic effects. Additionally, more maternal than paternal relatives participated in the study. However, while this might have affected the stability of the point estimate for the association of risk genotypes with the maternal vs. paternal line, it did not affect the magnitude or direction. The response rate was relatively low for our study, and the participation of families and of relatives within families could be biased and not reflect the true underlying distribution of families with NTDs in Ireland. However, selection for and participation in the study was independent of genotype and thus participants can be considered close to a random sample of relatives. The candidate gene approach used here evaluated a small number of polymorphisms and would have missed associations with other variants in folate metabolism pathway genes. An important limitation of our study (and others) is that we were not able to measure the mother's intake of folate and folic acid during pregnancy. The genes included in this study function in folate metabolism, so that their effect depends on the levels of folate present in the body. For example, high intake of folic acid and folate could mask genetic effects that would be seen at lower intake levels. Lastly, the number of multiple comparisons evaluated in our study likely produced some spurious findings.Our results are consistent with both genetic and epigenetic mechanisms contributing to the increased NTD and overall birth defects risk in the maternal lineage. The diversity of genetic risk seen in these families suggests that etiology of NTDs is multi-faceted. Future studies will benefit from including other relatives, especially grandparents, in addition to mothers, fathers, and affected individuals, especially if epigenetic mechanisms are to be addressed.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


CDH1) is involved in epithelial cell-cell interactions and plays important roles in the etiology of nephrolithiasis. We hypothesized that variants in the CDH1 gene are associated with risk of nephrolithiasis. In a hospital-based case-control study of 127 nephrolithiasis patients and 152 controls frequency matched by age and sex, we genotyped the functional -160C>A (rs16260) polymorphism and assessed its associations with risk of nephrolithiasis in a Chinese population. We found that the CA/AA genotypes were associated with a significantly decreased risk of nephrolithiasis , compared with the CC genotype, particularly among subgroups of BMI > 24 kg/m2 , age ≤ 57 years , and men . Our results suggest that the CDH1 polymorphism is involved in the etiology of nephrolithiasis and thus may be a marker for genetic susceptibility to nephrolithiasis.Nephrolithiasis is a common disorder worldwide. E-cadherin ( Nephrolithiasis is a common nephrologic disorder, with a lifetime incidence of ~10% . NephrolCDH1) plays a critical role in the establishment and maintenance of intercellular adhesion, cell polarity, and tissue architecture, which is expressed in almost all epithelial cells, including renal tubule cells [CDH1 in conjunction with renal cell injury, caused by oxalate crystals may contribute to the development of nephrolithiasis [CDH1 gene. Of these, a well known single nucleotide polymorphism (SNP) -160C>A (rs16260) has been identified in the promoter region, which has shown a 10~68% decreased level of transcriptional activity of the A allele compared to the C allele [E-cadherin  method. The PCR primers for the CDH1-160C>A polymorphism were 5’-TCCCAGGTCTTAGTGAGCCA-3’ (forward) and 5’-GGCCACAGCCAATCAGCA-3’ (reverse). The PCR reactions were performed in a total volume of 20µl containing 50ng genomic DNA, 1xTaq Buffer, 0.02mmol/L of MgCl2, 0.05mmol/L of dNTP mix, 10pmol/µl of each primer and 1U Taq DNA polymerase. After initial denaturation at 95°C for 5 min, the reaction was carried out at 95°C denaturation for 30 sec, 50°C annealing for 40 sec, and 72°C extension for 45 sec for a total of 34 cycles, and a final elongation at 72°C for 10 min. The amplified products were incubated with 5U of HphI (New England Biolabs) restriction enzyme at 37°C overnight. The restriction fragments were then analyzed by electrophoresis in 3% agarose gel stained with 0.5% ethidium bromide and photographed under UV illumination. Genotype analysis was performed by two persons independently in a blind fashion. About 10% of the samples were randomly selected for repeated genotyping for confirmation, and the results were 100% concordant.Genomic DNA was isolated from leucocytes of venous blood by proteinase K digestion and phenol/chloroform extraction. The CDH1-160C>A polymorphism between the nephrolithiasis cases and controls were evaluated by using the Student’s t-test (for continuous variables) or χ2-test . The associations between the CDH1-160C>A genotypes and risk of nephrolithiasis were estimated by computing odds ratios (ORs) and their 95% confidence intervals (CIs) from unconditional logistic regression analysis with the adjustment for age and sex. Hardy-Weinberg equilibrium (HWE) was tested using a goodness-of-fit χ2-test. For the stratification by age, the age cutoff of 57 years was used in this study. P < 0.05 was considered statistically significant, and all statistical tests were two sided. All the statistical analyses were performed with the software SAS 9.1.3 .Differences in the distributions of demographic characteristics and frequencies of genotypes of the P > 0.050). The age of the subjects ranged from 21 to 81 years. The mean age of the patients was 56.7 ± 10.2 years; the controls had a similar age distribution (57.3 ± 11.5 years). Men accounted for 65.4% of the patients and 63.2% of the controls. Furthermore, there was no significant difference in the body mass index (BMI) between the healthy subjects (23.8 ± 3.1 kg/m2) and nephrolithiasis patients (23.9 ± 3.0 kg/m2) (P = 0.831).The frequency distributions of selected characteristics of the cases and controls are presented in P = 0.034). The CDH1 A allele frequency was 0.181 among the cases and 0.280 among the controls, and the difference was statistically significant (P = 0.006). The observed genotype frequencies among the controls were in agreement with the Hardy-Weinberg equilibrium (P = 0.209). Logistic regression analysis revealed that the CA genotype, but not the AA genotype, was associated with a significantly decreased risk of nephrolithiasis, compared with the CC genotype . The A allele was associated with the decreased risk of nephrolithiasis in a dose–response manner (Ptrend = 0.010). Furthermore, a significant decreased risk of nephrolithiasis was found in the combined genotypes CA/AA compared with the CC genotype .As shown in CDH1-160C>A polymorphism on nephrolithiasis risk stratified by age, sex, and BMI . However, none significant gene-environment interaction was observed (data not shown).We further evaluated the effect of  and BMI . We founCDH1-160C>A polymorphism and risk of nephrolithiasis in a Chinese population. We found that the CA/AA genotypes were associated with a significantly decreased risk of nephrolithiasis, and the association was more evident in young men with BMI > 24 kg/m2.In this hospital-based case-control study, we investigated the association of the CDH1, an epithelial cellular junction protein expressed in renal tubule cells, contributes to the maintenance of epithelial development, organization, and cell integrity [-160C>A polymorphism has a significant effect on transcriptional activity of the promoter region; they demonstrated the in-vitro consequence of this polymorphism in decreasing gene transcription [CA/AA genotypes had a decreased risk of nephrolithiasis compared with those with the CC genotype. The possible explanation is that the A allele may result in the reduced urine calcium with the decreased formation of calcium oxalate crystals [Hypercalciuria is one of the main risk factors for nephrolithiasis. Most patients with nephrolithiasis have calcium-containing stones . Therefontegrity . Li et acription . In partcrystals .CASR) [FN 1) [CDH1 polymorphism, Tsai et al. analyzed 148 patients with calcium oxalate stone and 103 healthy controls for the polymorphism in the CDH1 3’-UTR, they found that a significantly increased risk of nephrolithiasis in a dominant model [-160C>A polymorphism was significantly associated with a decreased risk of nephrolithiasis in a Chinese population. The discrepancies between our current study and published studies might reflect differences in disease etiology and ethnic population [It has been reported that the some specific polymorphisms may be correlated with the increased risk of nephrolithiasis. For example, specific polymorphisms of the genes encoding vitamin D receptor (VDR) –16, vascCASR) , matrix CASR) , and fib) [FN 1)  were sugnt model . Howeverpulation . Other fCDH1 polymorphism on nephrolithiasis susceptibility.Several limitations of this study should be addressed. Our study was hospital-base study design, we cannot rule the possible of selection bias of subjects that may have been associated with a particular genotype. However, we applied rigorous epidemiological design by limiting factors of selection subjects and used further statistical adjustment to minimize the potential biases. In addition, our sample size is moderate, and the statistical power of the study is limited, especially for subgroup and interaction analyses. Therefore, large population-based prospective studies with ethnically diverse populations are warranted to further elucidate the impact of


Caspase-8 (encoded by the CASP-8 gene) is crucial in generating cell death signals and eliminating potentially malignant cells. Genetic variation in CASP8 may affect susceptibility to cancer. The CASP-8 −652 6N ins/del (rs3834129) polymorphism has been previously reported to influence the progression to several cancers. However, the overall reported studies have shown inconsistent conclusions. In this human genome epidemiology (HuGE) review and meta-analysis, the aim was to identify the association between CASP-8 −652 6N ins/del polymorphism and cancer risk. According to the inclusion criteria, 19 case-control studies with a total of 23,172 cancer cases and 26,532 healthy controls were retrieved. Meta-analysis results showed that the del allele, del allele carrier and ins/del genotype of −652 6N ins/del in the CASP-8 gene were negatively associated with cancer risk . In the subgroup analysis by ethnicity, the meta-analysis indicated that Caucasian populations harboring the del allele, del allele carriers and ins/del genotype had a lower cancer risk . In addition, a negative association was found between the del allele of −652 6N ins/del in the CASP-8 gene and cancer risk in the Asian population . In conclusion, this meta-analysis suggests that the del allele, del allele carrier and ins/del geno-type of the −652 6N ins/del polymorphism in the CASP-8 gene may be protective factors for cancer risk. Cancer is a leading cause of death worldwide, with millions of individuals succumbing to various types of cancer annually . TherefoSingle-nucleotide polymorphisms (SNPs) are the most common form of human genetic variation, leading to susceptibility to cancer. Findings of previous studies showed that some variants in CASP-8 gene are associated with susceptibility to various human cancers ,13. A caAn extensive electronic search of the PubMed, Cochrane Library, Embase, Web of Science, SpringerLink, CNKI and CBM databases was performed to identify relevant studies available up to May 1, 2012. The search terms used included  and  and . The references in the eligible studies or textbooks were also reviewed to check through manual searches to find other potentially eligible studies.The included studies had to meet the following criteria: i) case-control study focused on the associations between CASP-8 −652 6N ins/del polymorphism and cancer risk; ii) all patients diagnosed with a malignant tumor confirmed by pathological examination of the surgical specimen; iii) the frequencies of alleles or geno-types in case and control groups could be extracted; iv) the publication was in English or Chinese. Studies were excluded when they were: i) not case-control studies about CASP-8 −652 6N ins/del polymorphism and cancer risk; ii) based on incomplete data; iii) useless or overlapping data were reported; iv) meta-analyses, letters, reviews or editorial articles.Using a standardized form, data from published studies were extracted independently by two reviewers to populate the necessary information. The information extracted from each of the articles included: first author, year of publication, country, language, ethnicity, study design, source of cases and controls, number of cases and controls, mean age, sample, cancer type, genotype method, allele and genotype frequency, and evidence of Hardy-Weinberg equilibrium (HWE) in controls. In case of conflicting evaluations, an agreement was reached following a discussion with a third reviewer.Two reviewers independently assessed the quality of papers according to modified STROBE quality score systems ,16. Forthttp://ims.cochrane.org/revman/download) and STATA Version 12.0  software. Between-study variations and heterogeneities were estimated using Cochran’s Q-statistic  and 95% confidence interval (95% CI) were calculated using Review Manager Version 5.1.6  were associated with significantly lower cutaneous melanoma risk than were the ins/ins genotypes (CASP-8, located on chromosome 2q33–q34, encoded by the CASP-8 gene, is a caspase protein that plays a key role in the execution-phase of cell apoptosis . When in cancers . Frank europeans . In theienotypes . In our Limitations of this study should be acknowledged. First, although the funnel plot and Egger’s test did not show any publication bias, selection bias may have occurred because only studies published in English or Chinese were included. Second, the control subjects of the present study might not be representative of the general population, necessitating well-designed population-based studies with large sample sizes and detailed exposure information to validate our findings. Third, there was significant between-study heterogeneity from studies of the −652 6N ins/del polymorphism, while the geno-type distribution also showed deviation from HWE in some studies. Fourth, our meta-analysis was based on unadjusted OR estimates as not all published studies presented adjusted ORs, or when they did, the ORs were not adjusted by the same potential confounders, such as age, gender, ethnicity and exposures. In addition, our analysis did not consider the possibility of gene-gene or SNP-SNP interactions or the possibility of linkage disequilibrium between polymorphisms. Therefore, our conclusions should be interpreted with caution.In conclusion, findings of this study have shown a common insertion-deletion variation in the promoter region of the CASP-8 gene as a low penetrance susceptibility locus for certain common types of human cancers. The del allele, del allele carrier and ins/del genotype of the −652 6N ins/del polymorphism in CASP-8 gene may serve as protective factors for cancer risk. However, these findings should be validated by large-scale, prospective studies investigating more diverse ethnic groups and more detailed environmental exposure data.


In an attempt to resolve this issue, we conducted a meta-analysis.The Twenty-three separated studies involving 5939 EH patients and 5021 controls were retrieved and analyzed. Four ethnicities were included: Han, Kazakh, Mongolian, and She. Eighteen studies with 5087 EH patients and 4183 controls were included in the Han subgroup. Three studies with 636 EH patients and 462 controls were included in the Kazakh subgroup. The Mongolian subgroup was represented by only one study with 100 EH patients and 50 controls; similarly, only one study with 116 EH patients and 326 controls was available for the She subgroup. The pooled and ethnic group odds ratios (ORs) along with the corresponding 95% confidence intervals (95% CI) were assessed using a random effects model.α-adducin G460W gene polymorphism and EH in the pooled Chinese population under both an allelic genetic model  and a recessive genetic model . In contrast, no significant association between the α-adducin G460W gene polymorphism and EH was observed in the dominant genetic model . In stratified analysis by ethnicity, significantly increased risk was detected in the Han subgroup under an allelic genetic model  and a recessive genetic model .There was a significant association between the α-adducin G460W gene polymorphism was linked to EH susceptibility, most strongly in Han Chinese.In a Chinese population of mixed ethnicity, the  It is a polygenic hereditary disease with a complex pathogenesis that is strongly influenced by environmental and lifestyle factors. Previous studies have indicated that abnormal renal membrane ion transport might play a key role in the onset of EH α-adducin gene, located on 4p16.3, is composed of 16 exons. In 1997, Cusi et al first reported a missense point mutation substituting thymine (T) for guanine (G) at position 614 of the 10th exon, resulting in an expressed adducin α subunit with Trp (W) in place of the wild type Gly (G) at amino acid 460. In 2004, Beeks et al found that this α-adducin 460W mutant markedly influenced renal haemodynamics and function. The evident drop in effective renal blood flow and glomerular filtration rate (GFR) in the WW genotype led to excess water and sodium retention, even when patients maintained a low salt diet α-adducin G460W gene polymorphism does indeed increase susceptibility to a salt-sensitive form of hypertension The human α-adducin to salt-sensitive hypertension but have not investigated the specific polymorphisms. Confirmation of the α-adducin G460W gene polymorphism as a mediator of salt-sensitive hypertension would define a high value target for hypertension therapy.In China, hypertensive patients have three features: salt-sensitivity, great BP fluctuation, and high stroke morbidity. Approximately 60% of Chinese hypertensives are salt-sensitive . Recent studies have linked α-adducin G460W and EH has been demonstrated in Scandinavians and Japanese cohort α-adducin gene G460W polymorphism and hypertension in Caucasians, East Asians, South Africans, and African-Americans α-adducin G460W gene polymorphism and hypertension in Chinese population in another meta-analysis These association results are still controversial. An association between α-adducin G460W gene polymorphism and EH in Chinese population. The current meta-analysis encompassing 23 studies with 5939 EH patients and 5021 controls was important to be performed to derive a more precise estimate of the association between α-adducin G460W gene polymorphism and EH in individual ethnicities within China. Compared with Liu's work, there were some similarities. For example, two statistical models as recessive and dominant genetic models were adopted in both meta-analysises. There were 18 individual studies overlapped between them. Because of the limitations in Liu's work, subgroup analysis stratified by salt intake was additionally conducted in the Chinese Han population. Moreover, the retrieved individual studies were more comprehensive and exact than those in Liu's work. So the present meta-analysis has potential to add to the current knowledge.In consideration of these conflicting results and the above limitations, it is unclear yet whether there is a significant association between the α-adducin’, ‘polymorphism’, ‘hypertension’, ‘gene’, and Chinese'. The compiled data set was last updated on May 4, 2011, and included published papers from 1999 to 2011.The electronic databases PubMed, Embase, Web of Science, China Biological Medicine Database (CBMD), and China National Knowledge Infrastructure (CNKI) were searched for studies using the MeSH terms ‘hypertension’, ‘α-adducin G460W gene polymorphism and EH in a Chinese population, and (b) diagnosis of EH in agreement with the EH diagnosis criteria of the World Health Organization  where systolic blood pressure (BP)≥140 mmHg, diastolic BP≥90 mmHg, or treatment with antihypertensive medication defines EH.The reports included had to meet the following criteria: (a) evaluation of the No paper was included if it did not meet the two aforementioned inclusion criteria. When the same study results appeared in several papers, only one study was used in this meta-analysis. The extracted data included the first author's name, publication date, region of study, ethnicity of the sample population, number of genotypes, and the total number of cases and controls . Differeα-adducin G460W gene polymorphism and EH. The heterogeneity assumption was checked by the Chi-square-based Q-test and significance was set at P<0.05 2I where a higher value of 2I indicates heterogeneity. A random-effects model was used for all analyses (the DerSimonian and Laird method) α-adducin G460W gene polymorphism and EH. Meta-regression was performed to explore the sources of heterogeneity. Significance was set at P<0.05. The statistical analysis was performed using STATA 10.0 software .Three statistical models as allelic genetic models , recessive genetic models (TrpTrp vs.GlyGly+GlyTrp) and dominant genetic models (GlyGly vs. GlyTrp+ TrpTrp) were used in the current meta-analysis.The odds ratio (OR) and corresponding 95% confidence interval (CI) was used to examine the association between the Forty papers were retrieved by literature search, of which 23 conformed to the study inclusion criteria. Of the 17 excluded studies, 2 papers were published repeatedly, 5 papers were reviews, 2 deviated from HWE, and the remaining 8 did not focus on the G460W gene polymorphism . The totα-adducin G460W gene polymorphism and EH under an allelic genetic model  and a recessive genetic model . No significant association between the α-adducin Gly460Trp gene polymorphism and EH was observed in the dominant genetic model . In the stratified analysis, significantly increased risk was detected in the Han subgroup under an allelic genetic model  and a recessive genetic model . . , 3 and 4α-adducin G460W gene polymorphism and EH risk was significant in the Mongolian Chinese population under either the allelic genetic model  or recessive genetic model . There was no association evident in the Kazakh subgroup under an allelic genetic model  or a recessive genetic model . No significant association was found in the She subgroup under an allelic genetic model  or a recessive genetic model  (The association between  = 0.71)  and 3.Under a dominant genetic model, no significant increased risk was found in the Han subgroup , Kazakh subgroup , Mongolian subgroup  or She subgroup  α-adducin G460W gene polymorphism and EH might be strongly affected by salt intake. Mean salt intake level was quite different between local areas and ethnic groups in China. Accordingly, subgroup analysis was stratified into a high salt intake area and low salt intake area according to provincial statistics for the Han subgroup. Southern China was referred to as the low salt intake area and northern China was considered the high salt intake area α-adducin G460W gene polymorphism and EH was found in the low salt intake area under an allelic genetic model , a recessive genetic model  or a dominant genetic model . (The relationship between the = 0.81). , 6 and 7P = 0.014, 0.032, 0.042, 0.046) (P<0.05), while EH group sample size was not associated (P>0.05) , genotyping method were considered as the potential confounding factors. Among these factors, RR, genotyping method, total sample size and control group sample size might be possible explanations for the heterogeneity ((P>0.05)  and S4.α-adducin G460W gene polymorphism and EH under an allelic genetic model  or under a recessive genetic model . Similarly in subgroup 2, there was no significant association between α-adducin G460W gene polymorphism and EH under an allelic genetic model  or under a recessive genetic model . However, in subgroup 3, a significant association was observed between α-adducin G460W gene polymorphism and EH under an allelic genetic model  and under a recessive genetic model . . , 9.The funnel plot and Egger's test were used to assess the publication bias of the literature for the allelic genetic model. No evidence of publication bias was revealed by the funnel plot . No signα-adducin G460W gene polymorphism was significantly associated with EH susceptibility under both the allelic (OR: 1.12) and recessive genetic model (OR: 1.40), while no association was found using a dominant genetic model (OR: 0.88). However, in the subgroup analysis by salt intake area, a significant association was found under the allelic (OR: 1.19), recessive genetic model (OR: 1.60) and dominant genetic model (OR: 0.81) in the high salt intake area subgroup of Chinese Han population.In the current meta-analysis of 5,939 EH and 5,021 control Chinese subjects, the In China, EH increases gradually after 30 years of age and is as high as 18.8% in the total Chinese population. Among the EH patients, about 60% are classified as salt-sensitive. Salt-sensitive hypertension is controlled by genetics, but exacerbated by dietary habits. The ratio of salt-sensitive hypertensive to normotensives ranges from 15% to 42%, while the ratio of salt-sensitive hypertensives to all hypertensives ranges from 28% to 74% in different regions of China. Indeed, it is 28.57% in southern China and 58% in northern China α-adducin gene could influence Na, K-ATPase activity, thereby regulating water and sodium metabolism and affecting BP α-adducinα-adducin is clearly a critical target for hypertension treatment in China. Not unexpectedly, the question of whether there is an association between the α-adducin G460W gene polymorphism and EH in Chinese adults has received a great deal of attention.Allelic variance of the α-adducin G460W gene polymorphism and EH in the high salt intake area under the three genetic models, while no significant association was detected in the low salt intake area under the three genetic models. This result suggested that salt intake level actually had an effect on the relationship between the α-adducin G460W gene polymorphism and EH. Additionally, the higher OR in Mongolians might also reflect specific life-style factors like high salt intake  Differences in life styles might influence the role of the gene. For instance, the genetic effects were clearly different between the different salt intake areas α-adducin G460W gene polymorphism and EH was distinctly weakened but still just significant in subsection 3 with RR≤1.0. Therefore, further studies should match the sizes of the cases and control populations.In the meta-regression, the candidate confounding factors RR and genotyping methods were considered possible sources of heterogeneity. Indeed, the RR could partly explain the heterogeneity, indicating that the non-uniformity in the RR contributed to the between-study heterogeneity. The effect of genetics was greater in studies with RR≤1.0 than in other studies with RR>1.0, which suggested that the EH size and control size should be better balanced. After adjusting for RR, unexplained heterogeneity still existed. The association of the α-adducin Gly460Trp gene polymorphism and EH in China.The present meta-analysis results were generally consistent with the previous study by Liu α-adducin gene contributed to the susceptibility of EH in Chinese populations, especially in Han and Mongolia Chinese. Given that only one study has examined this relationship in Mongolian and She populations, additional studies should be launched to verify and extend these findings.In summary, the current meta-analysis suggested that the Gly460Trp allele of the Supplement S1Characteristics of the investigated studies of the association between the α-adducin G460W polymorphism and essential hypertension in the Chinese population.(DOC)Click here for additional data file.Supplement S2Summary of meta-analysis of association of α-adducin Gly460Trp gene polymorphism and EH risk in the Chinese population.(DOC)Click here for additional data file.Supplement S3The confounding factors for the potential sources of heterogeneity studied by meta-regression in Chinese Han population under an allelic genetic model.(DOC)Click here for additional data file.Supplement S4The meta-regression results among 18 studies in Chinese Han population under an allelic genetic model.(DOC)Click here for additional data file.


The risk stratification of patients for heart failure (HF) remains a challenge, as well as the anticipation of the response to β-blocker therapy. Since the pivotal role of β1 adrenergic receptor (β1-AR) in HF, many publications have studied the associations between the β1-AR polymorphisms (Ser49Gly and Arg389Gly) and HF, with inconsistent results. Thus, we performed a meta-analysis of studies to evaluate the impact of β1-AR polymorphisms on susceptibility to HF, the response to β-blocker therapy and the prognosis of HF.Electronic databases were systematically searched before August 2011. We extracted data sets and performed meta-analysis with standardized methods. A total of 27 studies met our inclusion criteria. It was found that in East Asians, the Gly389 allele and Gly389 homozygotes significantly increased the HF risk, while the Gly389 allele and Gly389 homozygotes trended to decrease the risk of HF in whites. With the similar reduction of heart rate, overall, the Arg389 homozygotes showed a better response to β-blocker therapy. Furthermore, the Arg389 homozygotes were significantly associated with better LVEF improvement in East Asians and a mixed population. And in white people, the Arg389 homozygotes made a greater LVESd/v improvement and trended to be associated with better LVEDd/v improvement. However, the prognosis of Arg389 homozygotes HF patients was similar to those with Gly389 carriers. The Ser49Gly polymorphism did not impact the risk or prognosis of HF.Based on our meta-analysis, the Gly389 allele and Gly389 homozygotes were risk factors in East Asians while trending to protect whites against HF. Furthermore, Arg389 homozygote is significantly associated with a favorable response to β-blocker treatment in HF patients. However, neither of the two polymorphisms is an independent predictor of the prognosis of HF. Heart failure (HF) is the end-stage of various heart diseases, and it represents a major health problem owing to its high prevalence, morbidity, mortality and significant health-care costs As the targets of endogenous catecholamines and β-blockers, β1 adrenergic receptor is known to play a pivotal role in the progression and treatment of HF Electronic searches by PubMed, Cochrane Library, and Chinese Biomedical Disc were used to identify published articles on β1 AR polymorphisms and heart failure. We combined search terms for “β1 receptor genetic polymorphism”, “ADRB1 polymorphism”, “Ser49Gly”, “Arg389Gly”, and all of the studies were published before August 2011. When more than one of the same patient population was included in several publications, only the most recent or complete study was identified in this meta-analysis.For the susceptibility to heart failure: (1) case–control studies, (2) evaluating the association between the β1 adrenergic receptor genetic polymorphisms and HF risk, (3) the diagnosis of HF was made according to the World Health Organization criteria, based on the presence of the typical clinical signs and symptoms of HF with left ventricular dysfunction.Response to β-blockers therapy: (1) The definition of HF was based on the World Health Organization criteria, (2) evaluation of β1 AR genetic polymorphisms on the reduction of heart rate (ΔHR), the changes of left ventricular ejection fraction (ΔLVEF), left ventricular end-diastolic diameter/volume (ΔLVEDd/v), left ventricular end-systolic diameter/volume (ΔLVESd/v), with at least 3 months follow up, (3) all the patients received β-blockers therapy, other medicines such as ACEI/ARB, diuretics, spironolactone, and digoxin were used when necessary.β1 AR polymorphisms and HF prognosis: (1) The definition of HF was based on the World Health Organization criteria, (2) evaluation of β1 adrenergic receptor genetic polymorphisms on all-cause mortality or combined end-point including death, heart transplantation and hospitalization, (3) patients were followed up for more than 1 year.All the searches were restricted to articles in English or Chinese. Case reports, editorials, and review articles were excluded.Two reviewers independently extracted data from published sources. The following information was extracted from each study: the first author, publication year, study design, ethnicity, sample size, distribution of genotypes, Hardy -Weinberg equilibrium (HWE) in controls, the parameters of therapy response , and the occurrence of death and combined end-point. We did not define any minimum number of subjects as required to include a study in our meta-analysis. If necessary data could not be extracted, the study authors were contacted by e-mail, with a reminder after 30 days. Disagreements were resolved by joint review and consensus.P<0.05 was considered that the distribution of genotypes in the control group deviated from HWE. Studies with controls not in HWE were subjected to a sensitivity analysis.Cochrane collaboration meta-analysis review methodology was used for this study In the meta-analysis of influence on HF patients therapy response and prognosis, comparisons of therapy response parameters  and prognosis  between Gly49 carriers (Gly49Gly + Ser49Gly) and Ser49 homozygotes, Gly389 carriers (Gly389Gly + Arg389Gly) and Arg389 homozygotes were carried out respectively.P<0.05 was considered statistically significant.The analysis was carried out using Review Manager statistical software . Pooled relative risk (RR) and associated 95% confidence intervals (CIs) were calculated for the risk and prognosis of HF. The therapy response was evaluated with weighted mean difference (WMD) for ΔHR and ΔLVEF, or standardized mean difference (SMD) for ΔLVEDd/LVEDv, ΔLVESd/LVESv. All tests and CIs were 2-sided, and a Ph <0.1), otherwise the random model (DerSimonian and Laird) was used 2 test, which described the proportion of variation in the log RR that is attributable to genuine differences across studies rather than to random error. I2 took values between 0% and 100% with higher values denoting greater degree of heterogeneity . Publication bias was assessed using a funnel plot of effect size against standard error.The presence of heterogeneity across studies was evaluated. The fixed-model (Mantel–Haenszel) was used when smaller heterogeneity were available . In subgroup analysis by ethnicity, in East Asians Gly389 allele increased the susceptibility to HF , and Gly389 homozygote was significantly associated with a 35% increased risk of HF compared with Arg389 carrier ; in contrast, Gly389 allele  and Gly389 homozygote  trend to decrease the risk of HF in whites. Among blacks, there was not a significant relationship between the Arg389Gly polymorphism and HF.The results for the associations between the β1 AR polymorphisms and the risk of HF were shown in Ph<0.01, I2 = 80%). The Gly49 allele significantly increased HF risk  compared with Ser49, while Gly49 carrier had significantly higher risk of HF than Ser49Ser homozygote . But neither of the associations was significant in sensitivity analysis. In ethnicity subgroup analysis, Gly49 significantly increased HF risk compared with Ser49  in East Asians, however, it was not robust either. No association between the risk of HF and Ser49Gly polymorphism was found in whites.For the Ser49Gly polymorphism, overall, the heterogeneity among studies was significant . Patients in the other 8 studies were mostly treated with β-blockers (at least 70%), and the kinds and dose of β-blockers  were decided by the subjects’ physicians. The patients were mostly whites in the 10 studies, in which the causes of HF were various (ischemic/IDCM/hypertension).P = 0.29, P = 0.37, P = 0.12, P = 0.76, There was no significant difference between Arg389 homozygotes and Gly389 carriers in all-cause mortality  Begg’s funnel plots were performed to access the publication bias of susceptibility to HF, response to β-blocker therapy and prognosis of HF. The funnel plots appeared symmetric, suggesting the absence of publication bias (data not shown).The purpose of diagnosing and treating HF is bringing about a reduction of mortality and morbidity. Preventive measurements can be undertaken early according to the risk factor for the development of HF, while appropriate therapeutic decision would be made by accurate prediction of response to β-blockers. Therefore, predictors of susceptibility to HF and response to β-blockers treatment are needed in clinical practice. Sustained sympathetic system activation has been shown to be deleterious to the failing heart, and the transmitters of this system, adrenaline and noradrenaline act on β-receptors situated on cardiomyocytes, which are mostly of the β1-subtype We have performed a meta-analysis on the impact of β1 adrenergic receptor polymorphisms on susceptibility to heart failure, response to β-blocker therapy and HF prognosis, including data on over 7000 patients and 3000 healthy controls. It has been found that Gly389 allele and Gly389 homozygote increased the risk of HF in East Asians, but trended to decrease the risk of HF in whites. Overall the response to β-blockers in Arg389 homozygote was greater than that in Gly389 carrier while the reductions of HR were similar. But the Arg389 homozygotes did not confer a significant prognosis benefit in heart failure patients. The Ser49Gly polymorphism was associated with neither risk nor prognosis of HF.There was evidence in transgenic mice to show that Arg389 allele was a risk factor of HF Furthermore, as a complex pathophysiological process, heart failure was involved in multi-genetic effection, thus other functional genes that affected the susceptibility to HF may mask the influence of β1 adrenergic receptor polymorphisms in different ethnics. In addition, environmental interactions  may also play a role in the pathogenesis of HF Experiments in mice and healthy volunteers showed that the reduction of HR to β-blocker in Arg389 homozygotes was greater than that in Gly389 carriers In another subgroup analysis, the Arg389 homozygotes performed a greater LVEF improvement to selective β1-blockers therapy than Gly389 carriers, but no differences were conferred by genotypes in the patients treated with non-selective β-blockers, as non-selective β-blockers also block β2 and α1 AR. The LVEF is an important indicator of response to treatment. Blockade of the β1AR is certainly responsible for a large degree of the improvement seen in HF, such as LVEF improvement and survival benefits, but it is not the sole mechanism. Previous studies have suggested that the release of norepinephrine is partly regulated by prejunctional β2-adrenergic receptors As the progression of heart failure is associated with LVEF, it is expected the Arg389 homozygotes would get a better efficacy by selective β1-blockers therapy and Gly389 carriers might benefit more from non-selective β-blockers, which needs further investigation.In a study of 54 patients with HF, individuals with the Gly49 variant had greater improvement in LVEDd Although the therapeutic response to β-blockers was influenced by the β1 AR polymorphisms, no differences were found in the prognosis of heart failure. In theory, a better beta-blocker response might lead to potential adverse outcomes, such as HF deterioration, hypotension and bradycardia. But by now, there has been no data supporting the association between the β1 genetic polymorphisms and the adverse outcomes in prognosis. It is also believed that in the failing heart the density of β AR, especially the β1 AR, kept decreasing In the future, large sample clinical trials which investigate both the response to beta-blockers and prognosis in the same group of patients may make more sense for this problem.First of all, we evaluated the relationships between heart failure and the two functional β1 AR polymorphisms, Ser49Gly and Arg389Gly respectively. Since the two polymorphisms are in strong linkage disequilibrium (LD) Secondly, in the 10 studies for prognosis of HF, the percentage of patients treated with beta-blockers ranged from 70% to 100%. The non-treated cases could not be excluded so that our results would inevitably be compromised. It’s a limitation of our meta-analysis. But in reality, some patients with heart failure due to the presence of contraindications cannot use β-blockers. Therefore, we believe that the current results were closer to clinical practice.At last, the sample size for each study was relatively small, even though all the studies in which the data could be achieved were collected for analysis, yet prospective studies with large sample size are warranted.Based on the present meta-analysis, we found that the Gly389 allele and Gly389 homozygote were associated with the increasing risk of HF in East Asians; but in whites, Gly389 allele and Gly389 homozygote trended to decrease the risk of HF. The Ser49Gly polymorphism of β1 receptor was not associated with risk of HF. With the similar reduction of heart rate, overall, the Arg389 homozygotes performed a better response to β-blocker therapy. Furthermore, the Arg389 homozygotes were significantly associated with better LVEF improvement in East Asians and mixed population. And in white people, the Arg389 homozygotes made a greater LVESd/v improvement and trended to be associated with better LVEDd/v improvement. However, neither of the two β1 AR polymorphisms impacted the prognosis of HF based on our data. The results of our meta-analysis would provide a reference for individualized treatment of HF, and are also helpful in future prospective clinical trials.Checklist S1(DOC)Click here for additional data file.