TCF7L2) has been shown to be associated with type 2 diabetes mellitus (T2MD) in multiple ethnic groups in the past two years, but, contradictory results were reported for Chinese and Pima Indian populations. The authors then performed a large meta-analysis of 36 studies examining the association of type 2 diabetes mellitus (T2DM) with polymorphisms in the TCF7L2 gene in various ethnicities, containing rs7903146 C-to-T (IVS3C>T), rs7901695 T-to-C (IVS3T>C), a rs12255372 G-to-T (IVS4G>T), and rs11196205 G-to-C (IVS4G>C) polymorphisms and to evaluate the size of gene effect and the possible genetic mode of action.Transcription factor 7-like 2 (OR). Publication bias and study-between heterogeneity were also examined.Literature-based searching was conducted to collect data and three methods, that is, fixed-effects, random-effects and Bayesian multivariate mete-analysis, were performed to pool the odds ratio : 1.790, 2.157), 1.406 , respectively, and the population attributable risk (PAR) for the TT/TC genotypes of this variant is 16.9% for overall. For T2DM and IVS4G>T polymorphism, TT homozygotes and TG heterozygotes versus GG homozygote was 1.885 , 1.360 , respectively. Four ORs among these two polymorphisms all yielded significant between-study heterogeneity (P < 0.05) and the main source of heterogeneity was ethnic differences. Data also showed significant associations between T2DM and the other two polymorphisms, but with low heterogeneity (P > 0.10). Pooled ORs fit a codominant, multiplicative genetic model for all the four polymorphisms of TCF7L2 gene, and this model was also confirmed in different ethnic populations when stratification of IVS3C>T and IVS4G>T polymorphisms except for Africans, where a dominant, additive genetic mode is suggested for IVS3C>T polymorphism.The studies included 35,843 cases of T2DM and 39,123 controls, using mainly primary data. For T2DM and IVS3C>T polymorphism, the Bayesian TCF7L2 gene are all associated with T2DM, and indicates a multiplicative genetic model for all the four polymorphisms, as well as suggests the TCF7L2 gene involved in near 1/5 of all T2MD. Potential gene-gene and gene-environmental interactions by which common variants in the TCF7L2 gene influence the risk of T2MD need further exploration.This meta-analysis demonstrates that four variants of  Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia that can occur through mechanisms such as impaired insulin secretion, insulin resistance in peripheral tissues and increased glucose output by liver . Most inTCF7L2) gene spans a 215,863 bases region on chromosome 10q25.3 [TCF7L2, activates many genes downstream of the Wnt signaling cascade [TCF7L2 is proglucagon, which encodes the insulinotropic hormone glucagon-like peptide 1 (GLP-1) [GLP1, in concert with insulin, plays a critical role in blood glucose homeostasis, it has been postulated that TCF7L2 gene variants may affect the susceptibility to type2 diabetes by indirectly altering GLP-1 levels [Transcription factor 7-like 2 ( 10q25.3  1147002002TCF7L2 10q25.3 . The mec cascade . One of  (GLP-1) ,50. BecaTCF7L2 gene consists of 14 exons and 13 introns (NCBI build 36.2). However, a previous study [TCF7L2 has 17 exons, of which five are alternative. There are at least four well-studied polymorphic markers that have brought the most attention, that is, (1) a C-to-T (genomic position: 114748339) substitution at snp rs7903146 of the intron 3 (IVS3C>T) [The human us study  has showIVS3C>T) ,54; 2)  TCF7L2 gIVS3C>T) ,55; (3) IVS3C>T) ; and (4)IVS3C>T) ,58. MostIVS3C>T) -65. TherIVS3C>T) ,58. The IVS3C>T) ,66, NortIVS3C>T) ,68, and IVS3C>T) ,70 populIVS3C>T) ,61,62,71PPARG, KCNJ11 and CPN10, appear to contain common variation that confers only 10–20% additional risk of T2DM, and only studies with large numbers of case and controls have had sufficient statistical power to examine their role robustly [TCF7L2, SLC30A8, HHEX, ETX2, CDKN2A/CDKN2B, IGF2BP2, CDKAL1, FTO, PPARG, and KCNJ11 have been found with susceptibility to T2DM [TCF7L2 gene polymorphisms and its association with T2DM has become the focus in diabetes mellitus, therefore, some meaningful results have reported one by one. In March, 2006, Grant and colleagues [TCF7L2 gene variants with T2DM. The study [TCF7L2 gene polymorphisms and T2DM. To exclude heterogeneity of these studies, we stratified the data by Hardy-Weinberg equilibrium (HWE), publishing time, ethnicity, body mass index (BMI), diagnosis and age.The polygenic basis of T2DM has been intensely investigated by large consortia worldwide, and consensus on a range of valid susceptibility genes has emerged. Such genes, for example robustly . Recent  to T2DM -76, and TCF7L2 gene and T2DM had been reported [TCF7L2 gene and T2DM, only summarized IVS3C>T polymorphism by just analyze allele frequency [TCF7L2 gene and T2DM, and then, to perform a detailed examination of sources of heterogeneity. We sought to estimate magnitude of the genetic association as well as the genetic mode of action, and to determine the extent of heterogeneity in the strength of associations between different studies.Although one meta-analysis  and severeported -80, Succreported  and publreported -76,81-83requency , the autTCF7L2 gene and T2DM published from March, 2006, when the association between TCF7L2 gene and T2DM was first reported [TCF7L2" or "TCF7L2 gene polymorphism", and "diabetes" or "diabetes 2" or "type 2 diabetes" or "type 2 diabetes mellitus" or "T2D" or "T2DM". The references of all computer-identified publications were searched for additional studies, and the PubMed option "Related Articles" was used to search for potentially relevant papers. Reference lists in retrieved articles were also screened.We conducted a comprehensive search of the US National Library of Medicine's PubMed, OMIM, ISI Web of Science, and Embase databases for all genetic association studies on at least one of the above four polymorphisms in the Searching was performed in duplicate by two independent reviewers (YZ and JYY). Without any language restriction , we only selected published manuscripts  if they met the following criteria: 1) the publication was a population-based association study (family-based study design with linkage considerations was excluded), regardless of sample size, and 2) there were enough results for extraction of data, that is, the number of subjects with each allele and genotype in the T2DM and control groups. Where eligible papers had insufficient information, we contacted authors by e-mail or mail for additional information. In the case of sequential or multiple publications of analyses of the same data or overlapping data sets, the publication that reported data from the largest or most recent study was included.Data were extracted independently and in duplicate by two investigators (YZ and JJY) who used the recommended guidelines for reporting on meta-analyses of observational studies . The folTCF7L2 gene polymorphisms and T2MD and to avoid excessive comparisons, we calculated the odds ratio by two methods, namely, allele comparison , and genotype comparison, that is, comparing the risk variant homozygotes and heterozygotes with wild homozygotes, respectively  and TC vs. CC (OR2) in IVS3C>T polymorphism; TT vs. GG (OR3) and TG vs. GG (OR4) in IVS4G>T polymorphism; CC vs. TT (OR5) and CT vs. TT (OR6) in IVS3T>C polymorphism; CC vs. TT (OR7) and CT vs. TT (OR8) in IVS4G>C polymorphism). We estimated and characterized the summary prevalence of risk allele by using only the data on controls. When we analyze genotype data for meta-analysis, cells with zero count had 0.5 been added. In addition, we calculated the population attributable risk (PAR) of risk allele according to method of Chang et al [We used the odds ratio as the metric of choice and it was estimated for each study. In order to explore the possible association between ng et al .We first compared alleles for cases and controls in order to detect overall differences and genetic association. Allele frequencies were computed for studies reporting only genotypic data. Pooled odds ratio were computed three times, by the fixed-effects method of Mantel and Haenszel , by the TCF7L2 gene polymorphisms and T2DM is based on genotype comparisons in order that magnitude of the genetic association and the genetic mode of action can be identified exactly. Once an overall gene effect was confirmed by the allele comparison, the genotype effects and genetic model were estimated by using the genetic model-free approach suggested by Minelli et al [OR1 to OR8 were calculated by using multivariate meta-analysis with Bayesian method [OR2 versus logOR1 for λ1, logOR4 versus logOR3 for λ2, logOR6 versus logOR5 for λ3, and logOR8 versus logOR7 for λ4, were calculated [Our primary analysis for li et al , where nn method . The loglculated . The parlculated  and by tlculated . Unless P values of HWE or not. For above allele-based and genotype-base analyses, we took two methods to handle Hard-Weinberg disequilibrium. Firstly, we performed sensitivity analyses by including by including and excluding studies in Hard-Weinberg disequilibrium . Secondly, we included all studies regardless of HWE and instead adjusted for the degree of disequilibrium by using the inbreeding coefficient (F) suggested by Trikalinos et al [F was estimated for each study by using data in the control group. Predicted genotype frequencies were estimated [We tested for deviations from Hard-Weinberg equilibrium (HWE) in both case and control populations by using the exact method reported by Emigh et al  whether os et al . Brieflystimated  and usedQ statistic [P value less than 0.10 [I2 statistic, which describes the percentage of variability in point estimates due to sample heterogeneity rather than sampling error [I2 values less than 25 percent may be considered "low", values of 31 percent to 56 percent have been defined as indicating "low" to "moderate" heterogeneity, whereas values greater than 56 percent are considered indicative of "notable" heterogeneity, and "large" heterogeneity is stipulated for I2 values of larger than or equal to 75 percent [OR1 and OR2 for IVS3C>T polymorphism, OR3 and OR4 for IVS4G>T polymorphism, OR6 and OR7 for IVS3T>C polymorphism, OR7 and OR8 for IVS4G>C polymorphism) in genotype-based analysis. If there was heterogeneity on at least one of these two odds ratios, the source of the heterogeneity was explored by fitting a covariable  in a meta-regression model [2) vs. abnormal (≥ 30.0 kg/m2) according to the meta-regression analysis. Logistic regression analysis was used to compare odds ratios among these possible groups. In addition, genetic association studies may be especially susceptibility to the selective publication of positive findings on gene association [In sensitivity analysis, we estimated between-study heterogeneity across all eligible comparisons using Cochran's tatistic . Heteroghan 0.10 . We alsong error ,94, and ng error . As a gu percent . The exaon model -98. Possociation . In ordeociation  and cumuociation  were usemeta, metan, metabias, metacum, and metareg commands, except for the Bayesian method of genotype-based analysis. We fit the Bayesian models by using Markov chain Monte Carlo (MCMC) methods with Bayesian framework and perform our inferences using WinBUGS 1.4.3 [CrI) describes a range in which the probability that the unknown quantity lies within this interval, after seeing the data, is 95%. A 'burn-in' of 10,000 iterations is carried out for models, followed by 50,000 iterations for parameter estimates. A P value less than 0.05 was considered statistically significant, except for tests of heterogeneity, where a level of 0.10 was used.All analyses were conducted in Stata software, version 9.0 , using mGS 1.4.3 , taking TCF7L2 gene polymorphisms and T2DM were identified by the inclusion criteria and all of them were written in English  for IVS3C>T polymorphism, IVS3T>C polymorphism, IVS4G>T polymorphism and IVS4G>C polymorphism, respectively.There was considerable diversity of ethnic groups. Eligibility criteria for T2DM patients were shown in Table 1 , corrected P = 0.379 (corrected z = 0.88), and corrected P = 0.426 (corrected z = 0.80), respectively. Figure TCF7L2 IVS3C>T polymorphism has remained significant and been consistent over time  vs. C homozygotes (CC), and heterozygotes (TC) vs. C homozygotes (CC) are indicated in figure TCF7L2 gene among controls was 20.2 percent : 16.3, 24.1) and was considerable variation in different ethnic populations ; for North Europeans, 21.9% ; for East Asians, 3.2 ; for Indians, 28.1% ; for others, 23.0% ). We first contained all the 35 studies to evaluate the overall association between TCF7L2 IVS3C>T polymorphism and T2DM. With our allele-based analysis, the pooled odds ratio suggested a 1.416-fold increase in susceptibility to T2DM among persons with the T allele , with a finding that was highly statistically significant (P = 0.000), but there was significant between-study heterogeneity   and TC versus CC (OR2) were calculated for each study (data are not shown and available from the first author on request). In our primary concern, multivariate meta-analysis was conducted to estimate the pooled effects and there was an significant increased risk of T2DM among populations with both homozygous variant TT genotype : 1.790, 2.157) and heterozygous variant TC genotype , with a "moderate" between-study heterogeneity , which suggested a codominant genetic mode of action.The genotype frequency of OR1 (meta-regression beta coefficient (β) = -0.0993, P = 0.002) and lnOR2 . We then did a subgroup analysis by stratifying study samples into five ethnic groups, that is, Caucasians (11 samples), North European (6 samples), East Asian (9 samples), Indians (4 samples) and other racial descent group (5 samples), and found that this stratification can remove all the between-study heterogeneity among North Europeans, East Asians and Indians for both OR1 and OR2, rather than that among Caucasians and other racial group , 1.989 , 1.944 , 1.802 , 1.669 (95%CrI: 1.373. 2.104), and 1.595 , respectively, and the pooled OR2 by descending ranking was 1.766  for French Caucasians, 1.696  for Africans, 1.406  for Indians, 1.357  for North Europeans, 1.352  for East Asians, and 1.349  for other Caucasians  for Africans, 0.676  for Indians, 0.670  for East Asians, 0.511  for French Caucasians, 0.472  for North Europeans, and 0.436  for other Caucasians, which suggested codominant genetic mode of action among these different ethnic populations except for Africans where dominant mode of action was found.Meta-regression was used to explore the source of heterogeneity and it was found that ethnicity was the only co-variable associated with both lnOR1 and lnOR2 by separate meta-regression analysis, the significant association was found when we evaluate it together with ethnicity . In addition, some references reported that BMI may interact with TCF7L2 gene to increase the risk of T2MD. Therefore, we did a subgroup analysis for BMI  vs. abnormal (≥ 30.0 kg/m2). However, such stratification cannot remove heterogeneity for both lnOR1  and lnOR2 . The pooled OR1, OR2, and λ1 for populations with normal BMI were 2.017 , 1.470 , and 0.554 , respectively. The pooled OR1, OR2, and λ1 for populations with abnormal BMI were 1.931 , 1.337 , and 0.441 , respectively. Logistic regression analysis indicated that there was no significant difference between populations with normal and abnormal BMI for both lnOR1 (P = 0.855) and lnOR2 (P = 0.716).Although BMI was not associated with both lnOur searches identified 29 studies  meeting our inclusion criteria. All of these studies examined the IVS4G>T polymorphism , corrected P = 0.536 (corrected z = 0.62), and corrected P = 0.442 (corrected z = 0.77), respectively. Figure TCF7L2 IVS4G>T polymorphism has remained significant and been consistent over time  vs. G homozygotes (GG), and heterozygotes (TG) vs. G homozygotes are shown in figure e figure .TCF7L2 gene among controls was 18.0 percent  and was considerable variation in different ethnic populations ; for North Europeans, 22.3% ; for East Asians, 2.1 ; and for Indians, 23.1% ). We first contained all the 29 studies to evaluate the overall association between TCF7L2 IVS4G>T polymorphism and T2DM. With our allele-based analysis, the summary odds ratio suggested a 1.379-fold increase in susceptibility to T2DM among persons with the T allele , with a finding that was highly statistically significant (P = 0.000), but there was significant between-study heterogeneity   and TG versus GG (OR4) were calculated for each study (data are not shown and available from the first author on request). In our primary concern, multivariate meta-analysis was conducted to estimate the pooled effects and there was an significant increased risk of T2DM among populations with both homozygous variant TT genotype : 1.698, 2.088) and heterozygous variant TG genotype , with a "moderate" between-study heterogeneity both in the former , which suggested a codominant genetic mode of action.The genotype frequency of OR3  and lnOR4 . We then did a subgroup analysis by stratifying study samples into five racial descent groups, that is, Caucasians (9 samples), North European (4 samples), East Asian (8 samples), Indians (4 samples) and other racial descent group (4 samples), and found that this stratification can remove all the between-study heterogeneity among North Europeans, East Asians and Indians for both OR3 and OR4, rather than that among Caucasians and other ethnic group  and OR4   by descending ranking, that is, Caucasians, North Europeans, East Asians and Indians, was 2.091 ), 1.889 , 1.875 (95%CrI: 0.464~3.439), and 1.593 , respectively, and the pooled OR4 by descending ranking was 1.569  for East Asians, 1.413 ) for Caucasians, 1.380  for North Europeans, and 1.358  for Indians  for East Asians, 0.657  for Indians, 0.507  for North Europeans, and 0.470  for Caucasians , which suggested codominant genetic mode of action among all these four ethnic populations.Meta-regression was used to explore the source of heterogeneity and it was found that ethnicity was the only co-variable associated with both lnOR3 and lnOR4 by separate meta-regression analysis, the significant association was found when we evaluate it together with racial descent . In addition, some references reported that BMI may interact with TCF7L2 gene to increase the risk of T2MD. Therefore, we also did a subgroup analysis for BMI in this polymorphism. However, such stratification can remove few heterogeneity for both lnOR3  and lnOR4 . The pooled OR3, OR4, and λ2 for populations with normal BMI were 1.795 , 1.397 , and 0.572 , respectively. The pooled OR3, OR4, and λ2 for populations with abnormal BMI were 1.957 , 1.343 , and 0.442 , respectively. Logistic regression analysis indicated that there was no significant difference between populations with normal and abnormal BMI for both lnOR1 (P = 0.069) and lnOR2 (P = 0.152).Although BMI was not associated with both lnORCvT = 1.323, 95% CI: 1.232, 1.419, P = 0.000; Q = 12.615, P = 0.181, I2 = 28.7 percent) and the C allele of IVS4G>C polymorphism ; random-effects ORCvG = 1.238, 95 percent CI: 1.153, 1.330, P = 0.000; Q = 20.968, P = 0.102, I2 = 33.2 percent) were significantly associated with T2DM , 1.292 , and 0.450 , respectively. The pooled OR7, OR8, and λ4 for IVS4G>C polymorphism were 1.471 , 1.242 , and 0.561, respectively. These all suggested a codominant genetic mode of action among such two polymorphisms. We did not find any evidence of small sample bias and publication bias for any of the studies , and cumulative meta-analysis results for both allele-based and genotype-based analysis of the above two polymorphisms were stable (data and figure are not shown and available from the first author on request).The C allele of IVS3T>C polymorphism ; random-effects TCF7L2 gene polymorphisms and susceptibility to T2DM. We find that near 70,000 subjects  were from 35 studies concerning the IVS3C>T polymorphism, and over 55,000  subjects were from 29 studies investigating the IVS4G>T polymorphism. These two variants were the main study focus on the association between TCF7L2 gene polymorphisms and susceptibility to T2DM.This is a large meta-analysis, including data from 25 papers involved in 36 genetic association studies with exactly 35,843 cases of T2DM and 39,123 controls, carefully avoiding the double-counting of participants in the study. The HuGE systematic review provides the most recent and comprehensive evaluation of the association between four TCF7L2 gene polymorphisms, namely, IVS3C>T as well as IVS4G>T, and T2DM. The magnitudes of this association were moderate, however, statistically significant. Our primary analysis finds that among IVS3C>T polymorphism, TC heterozygotes carry just over a 1.4-fold increased risk of T2MD, and TT homozygous variants carry near a 2.0-fold increase in T2MD risk when compared with CC homozygotes, and that among IVS4G>T polymorphism, TG heterozygotes carry near a 1.4-fold increased risk of T2MD, and TT homozygous variants carry approximate a 1.9-fold increase in T2MD risk when compared with GG homozygotes. Significant magnitudes of genetic effect for heterozygotes of these two variants were confirmed by the analysis on the pooled odds ratios among different ethnic groups with slight differences except for East Asians where higher pooled odds ratio was observed in IVS4G>T polymorphism when compared with that of the other ethnic populations, and genetic effect sizes for homozygotes of these two variants were also strengthened by the analysis on the pooled odds ratios among different ethnic groups including Caucasians, North Europeans, Africans and Indians by showing a small variation. However, we found that there was no significant association between such two homozygotes and disease among East Asians, and therefore, conflicting results have appeared, in which studies on Chinese provided negative results [TCF7L2 is the most common susceptible gene for T2DM among various ethnic groups in the world.On one hand, the results indicates notable associations between two main  results ,71, howe results ,62,82. OCIs among all these four TCF7L2 gene polymorphisms. We also explored the genetic mode among different ethnic populations and similar results were observed in Caucasians, North Europeans, East Asians and Indians except for Africans, where dominant genetic mode is suggested for IVS3C>T polymorphism. We cannot verify the genetic mode of action for Africans in the other three polymorphisms due to few studies. In addition, genetic mode of IVS3C>T variant among Africans also need a further verification by more studies. Even so, we nevertheless suggest a potential multiplicative genetic model for the four TCF7L2 gene polymorphisms.On the other hand, we made no assumptions about genetic models and finds that the pooled odds ratios can clearly fit a multiplicative model and the lambda (λ) parameter can well-done indicate a codominant genetic mode of action with tight TCF7L2 and T2MD performed by Cauchi et al [TCF7L2 according to IVS3C>T variant and the PAR for the combined genotypes TT and TC were 16.9, 23.2, 14.1, 2.5, 17.9, 27.0 for overall, Caucasians, North Europeans, East Asians, Indians, and Africans, respectively, suggesting this gene polymorphism may contribute near 1/5 of all T2MD in the globe except for East Asians.The effect size of overall association between IVS3C>T variant and T2MD is near to 1.42, which is lower than that in a former meta-analysis about hi et al , and larhi et al ,74,76. whi et al ,57,71,88OR1 and OR2), and IVS4G>C polymorphism (OR3 and OR4). In this Human Genome Epidemiology review, we examined five potential sources of between-study heterogeneity for genotype-based model by meta-regression and it was suggested that ethnicity was the only co-variable associated with the four ORs. In fact, more detailed manner of ethnic stratification, namely, French Caucasians, other Caucasians, North Europeans, East Asians, Indians, and Africans, can remove near all the heterogeneity of studies about both IVS3C>T and IVS4G>C polymorphisms for OR1 to OR4. Study results reported by several articles showed that BMI may cooperate with the TCF7L2 gene to increase the risk of the T2DM. However, disagreement of the results was published by different researchers. Cauchi et al[2) and more higher allelic ORs or RRs were obtained in IVS3C>T and IVS4G>C polymorphisms; whereas, Miyake et al [TCF7L2 gene on T2DM by a indirect action; on the other hand, were difficult for us to explain the deep-seated reasons that how the BMI influence the effect of TCF7L2 gene on T2DM because we cannot gain the original data of BMI in each article. This is a general limitation of meta-analysis. So we hope the reasonable interpretation will be presented in the subsequent studies. Although sex [TCF7L2 gene, we cannot test the effects of age, sex, drugs and lifestyle on heterogeneity due to without sufficient related data being used. In addition, the age of the control NGT groups may be associated with the heterogeneity and the young controls may develop diabetes at a later date. However, there are also insufficient data.Our findings were based on some gene-association studies and tens of thousands participants and were robust to each of the planned sensitivity analyses used. We cannot find any evidence of publication bias and small study bias by funnel plots and cumulative meta-analysis, but, considerable between-study heterogeneity was found. Between-study heterogeneity may be due to differences in sample selection , or in methods , or it may be due to real differences in populations , or in interactions with other risk factors . The results of primary analysis (genotype-based) on the four polymorphisms showed statistically significant between-study heterogeneity for both IVS3C>T polymorphism . As a matter of fact, T2DM appears to be composed of subtypes where genetic susceptibility is strongly associated with environmental factors at one end of the spectrum, and highly genetic forms at the other end. Thus, there are several possible interactions between gene and gene or between gene and environmental factors.ORTvC≈1.42) was recently mapped to the transcription factor TCF7L2, a gene that is a target of the Wnt signaling pathway [HHEX, IDE, DKK3 and KIF11, which are also in the Wnt signaling pathway [TCF7L2 on the risk of T2DM. Cauchi et al [TCF7L2 gene was downregulated in obese subjects developing T2DM and they then brought forward a hypothesis of a potential interaction between TCF7L2 and Calpain-10 by a supporting material [TCF7L2 gene and β-catenin gene [TCF7L2 other related genes. These hypothetical interactions and their specific effects on T2DM, as well as functional analyses, will be required to further elucidate the role of variation in TCF7L2 in the pathogenesis of T2MD and very large samples are needed.Recent years, a series of new loci in some genes have been identified to contribute about 10~30% population attributable risk (PAR) of T2DM -76,107.  pathway . Whereaf pathway -113 may hi et al found thamaterial  that sugnin gene . HoweverTCF7L2 gene to influence T2DM. So far, few specific gene-environment interactions have been described for TCF7L2 gene polymorphisms. Because obesity is a major determinant of development of T2DM, most patients with T2DM are obese when they develop diabetes, and obesity aggravates the insulin resistance. BMI and waist circumstance may become the main focus on attention of interactions, particularly in studies of IVS3C>T and IVS4G>C polymorphism among T2DM. Cauchi and colleagues [T2D had a interaction with BMI, and that the former was associated with increased BMI, whereas the latter was associated decreased BMI. Florez et al [TCF7L2 gene polymorphisms should be interpreted extremely cautiously, however, and much larger and more detailed studies are looked forward to substantiating such putative interactions with appropriate power and rigor. Complementarily, Smoking and drinking were important risk factors to influence on T2DM and they can also interact with genetic factor to increase the risk of this disease [TCF7L2 gene polymorphisms and smoking or/and drinking in all the open publications. This is a meaningful and valuable domain to explore.A variety of environmental factors can be implicated in the phenotype of T2DM, such as obesity, hypertension, bad lifestyle , short of exercise, malnutrition, and some drugs . All thelleagues  reportedlleagues  found a lleagues  replicatlleagues  discoverez et al , observeez et al . These e disease . We founTCF7L2 gene polymorphisms, the lack of data available to us on most of those environmental factors (except for obesity) and genes was a limitation, which we hope will be demonstrated by the following studies.The lack of information especially the genotype data from some articles was the main limitation, we have done our possible to contact exhaustibly to the authors of publication that did not provide the original data and obtained full data on about 75 percent of subjects involved in various ethnic populations. Next, the quality of diagnosis, match, and genotyping varied a lot among studies, but the summary results were not changed when these questions were discussed carefully. There was considerable heterogeneity in IVS3C>T and IVS4G>T polymorphisms in our initial results. However, we discovered the main sources of the heterogeneity and were able to remove it finally. A question we cannot resolve is that how the four snps discussed here in strong LD will lead to differences in T2DM association among diverse populations. Besides, since environment factors and genes, such as obesity, smoking, drinking, and hypertension as well as plasma TG, and gene related to the Wnt signaling pathway are strong candidates for a potential interaction with TCF7L2 gene and T2DM both overall and in Caucasians, North Europeans, East Asians, Indians, and Africans, and suggested a potential multiplicative genetic model for all the four polymorphisms of TCF7L2 gene among different ethnic populations except for Africans, where additive genetic mode is suggested for IVS3C>T polymorphism. Our study results also suggest that IVS3C>T and IVS4G>T variants of TCF7L2 gene can be taken as reference loci for exploring T2DM susceptibility. We found and removed the main source of heterogeneity; however, we cannot find any evidence of bias. Furthermore, we estimated the potential gene-gene and gene-environmental interactions by which common variants in the TCF7L2 gene influence risk of T2DM. These two domains are just the recommendation for future researches.This large meta-analysis summarizes the strong evidence for an association between HuGE: Human Genome Epidemiology; T2DM: type 2 diabetes mellitus; TCF7L2: Transcription factor 7-like 2; CI: confidence interval; CrI: credible interval; OR: odds ratio; NGT: normal glucose tolerant; BMI: body mass index; HWE: Hardy-Weinberg equilibrium.The authors declare that they have no competing interests.BZ, YT, YL, and YZ carried out the design of this meta-analysis, analyzed the data and drafted the manuscript. YZ and JYY conducted a searching, data extraction, and statistical analysis on the manuscript. YWZ performed a searching and data extraction on the manuscript. HCL participated in designing and writing for the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:Title: Tables. Tables 1 – 6.Click here for file


The physiopathology of dengue hemorrhagic fever (DHF), a severe form of Dengue Fever, is poorly understood. We are unable to identify patients likely to progress to DHF for closer monitoring and early intervention during epidemics, so most cases are sent home. This study explored whether patients with selected co-morbidities are at higher risk of developing DHF.A matched case-control study was conducted in a dengue sero-positive population in two Brazilian cities. For each case of DHF, 7 sero-positive controls were selected. Cases and controls were interviewed and information collected on demographic and socio-economic status, reported co-morbidities  and use of medication. Conditional logistic regression was used to calculate the strength of the association between the co-morbidities and occurrence of DHF.170 cases of DHF and 1,175 controls were included. Significant associations were found between DHF and white ethnicity , high income , high education , reported diabetes  and reported allergy treated with steroids . Black individuals who reported being treated for hypertension had 13 times higher risk of DHF then black individuals reporting no hypertension.This is the first study to find an association between DHF and diabetes, allergy and hypertension. Given the high case fatality rate of DHF (1–5%), we believe that the evidence produced in this study, when confirmed in other studies, suggests that screening criteria might be used to identify adult patients at a greater risk of developing DHF with a recommendation that they remain under observation and monitoring in hospital. Dengue is an arboviral disease that affects large areas of countries in tropical and subtropical regions of the world. Around 500,000 cases and 22,000 deaths of dengue hemorrhagic fever (DHF)/Dengue Shock Syndrome (DSS), the most severe presentations of this disease, occur annually. It is unclear why some cases of dengue fever (0.5% to 4%) progress to DHF/DSS. There is weak evidence that some diseases could have a role in this process, such as diabetes, hypertension, and allergies. In epidemics most dengue fever cases are sent home as there are too many to be kept in observation, but if it were possible to identify those with a higher risk of progression to DHF, they could be kept for observation, for early detection of signs, symptoms and alterations in laboratory tests suggestive of DHF, to enable timely and effective clinical management and early intervention. We study this issue and we believe that the evidence produced in this study, when confirmed in other studies, suggests that screening criteria might be used to identify adult patients at a greater risk of developing DHF with a recommendation that they remain under observation and monitoring in a hospital. Dengue is the most important viral vector-transmitted disease worldwide in terms of the total number of cases, disease morbidity and mortality th parallel north to the 35th parallel south According to the World Health Organization (WHO) It is not clear why some cases of dengue progress to DHF; understanding this process is essential for preventing it. There is evidence that sequential infections by different dengue viral serotypes plays a important role This is a matched case-control study carried out in two coastal cities in the northeast of Brazil, Salvador and Fortaleza, with populations of roughly two and a half million each. The minimal sample size (159 cases and 636 controls) was determined to be able to detect an increase of 2.3 fold in the risk of DHF in cases of dengue who also had diabetes , with 95% precision, 80% power and a ratio of at least 4 controls for each case. We eventually studied 170 cases and 1,175 controls.The study population consisted of subjects with a history of dengue, confirmed serologically. Only cases and controls who tested positive (IgG) for the anti-dengue antibodies were included in the study, since we wanted to investigate reasons for progression to DHF, not for infection with dengue virus. Cases were selected among those notified with dengue hemorrhagic fever during the period 2002 and 2003 in Salvador and 2003–2005 in Fortaleza. In Salvador the research was conducted in 2004, while in Fortaleza, it was conducted in 2005.3). We did not consider ascites, pleural effusion, as these were very rarely recorded in the SINAN at the time. In Salvador, of the 91 cases of DHF notified to SINAN, 26 did not meet the criteria and were not included in the study and 65 met the criteria and were invited to participate in the study; 55 agreed to participate. No deaths from DHF were recorded during the study period. In Fortaleza, 194 cases of DHF were notified to SINAN, 55 did not meet the criteria and 139 were invited to participate in the study. Of these 5 had died from others causes since the notification, and 19 refused to participate. The remaining 115 were included in the study. Cases which were excluded had severe dengue but did not meet the criteria for DHF or their records did not have sufficient information.Selection of cases: Cases of DHF registered in the national surveillance system (SINAN) in residents of these two cities between 2003 and 2005 were identified as potential cases for the study. Their surveillance records were examined by two physicians and included in the study if they met the criteria for DHF used by Brazilian Health Service For each case, a pool of 7–8 potential controls were selected from individuals living in the neighborhood of each case, according to a rule  matched by sex and age (within five years), and who reported dengue fever in the same year as the case. Blood was drawn from the pool of potential controls by venous puncture for exclusion of those without seropositivity for dengue. The serum was separated by centrifugation and stored at −20°C. The Department of Arbovirology and Hemorrhagic Fevers of the Evandro Chagas Institute performed ELISA for anti-dengue IgG antibodies, with titers were above 1∶40 Cases and controls were interviewed (during 2005–2006) at home by teams of trained interviewers using a previously tested, standardized questionnaire, collecting the following types of information: demographic and biological , socio economic  and self-reported skin color. Clinical information collected included signs and symptoms of dengue and reported morbidity with respect to diabetes, hypertension, allergy, asthma, kidney failure, liver failure and sickle-cell anemia at the time of the reported dengue, and use of medication for these illnesses at the moment of the interview. When the individual reported having had one of these conditions, he/she was asked whether the diagnosis had been made by a doctor and the interviewer asked to see the prescription and/or packaging of any medication. To avoid bias, interviewers were blind to the study objectives and all field work was supervised.Analysis: To reduce the data, cases and controls were grouped according to their biological and social characteristics and the frequency of self-reported chronic diseases. Reported kidney failure, liver failure and sickle-cell anemia were not considered in this analysis because they were either not reported or reported by very few cases or controls.The crude association (OR and 95%CI) between the predictors of interest, presence of co-morbidities  and outcome of interest, presence of DHF was investigated using cross tabulations based on matched pair analysis, the McNemar's test Ethical approval was granted by the Research Ethics Committee, Instituto de Saúde Coletiva, Federal University of Bahia, Salvador, Brazil. Cases and controls who agreed to participate in the study gave written informed consent.Of the 170 cases of DHF included in the study, 55.9% were women and around 80% occurred in individuals over 15 years of age. With respect to skin color, 43.5% of cases considered themselves white, 50.0% mixed race and 6.5% black. Over 51% of cases had 11 years or more of schooling and 47.1% had an income of at least four minimum salaries. Of the 1,175 controls, 54.6% were female, 80.9% were over 15 years of age; 27.1% considered themselves white, 64.5% mixed race and 8.4% black; 31.5% had 11 years or more of schooling; and 17.5% had an income of at least 4 minimum salaries. Of these demographic variables, statistically significant differences (p<0.05) were found between the two groups only with respect to skin color, years of schooling and family income. Statistically significant differences (p<0.05) were also found between the cases and controls with respect to self-reported diabetes and allergy .Skin colWhen each one of the self-reported chronic diseases was adjusted for the ethnic and social variables, only diabetes remained associated with DHF  .When the self-reported diseases were classified according to use of the respective medications, with the category “absence of disease” as reference, the use of medication (steroids and no steroids) by allergic individuals was found to be positively associated with DHF; however, following adjustment for the ethnic and social variables, the association was maintained only for allergy treated with steroids . Of the individuals who reported hypertension, an increasing gradient was found in the crude and adjusted OR when the use of medication was considered ; however, these differences were not statistically significant .In the subgroup analysis of the cases and controls who described themselves as black, the individuals who had hypertension and used more than one antihypertensive medication were found to have a 13-fold greater likelihood of having DHF (95%CI: 1.42–118.8) compared to black individuals who did not have hypertension. Black individuals with hypertension who did not use medication or who used only one type of antihypertensive medication were around four times more likely to have had DHF when compared to black individuals without hypertension; however, this difference was not statistically significant(data not shown on tables).The results of this study showed that individuals who reported having allergies (and for which they used steroids), or those who reported diabetes, were two and a half times as likely to have DHF. DHF is known to be more common in repeat dengue infections. Current knowledge about the physiopathology of DHF suggests amplification of the immune response due to the presence of heterotypic antibodies against a serotype of the dengue virus at the time of new infection Although no statistically significant association was found between hypertension and DHF, it is interesting that when individuals without hypertension were taken as a reference group, a clear trend was found for an increased likelihood of DHF among those who reported having hypertension but did not use any antihypertensive medication followed by hypertensive individuals who used more than one antihypertensive drug. On the other hand, the thirteen-fold higher association between individuals who consider themselves black and use an antihypertensive drug and DHF, when compared with non-hypertensive black individuals, strengthens the hypothesis that preexisting diseases in which physiopathology detrimentally affects endothelial function may help trigger the phenomenon of fluid shift resulting from the increased vascular permeability that characterizes DHF.in vivo study associated these differences with genetic markers of African ancestry The increase in DHF in subjects with white skin color is well described The growth in the frequency of allergic and atopic diseases that has been observed in recent decades has emphasized the need for research studies capable of explaining the mechanisms involved in this phenomenon. Changes in lifestyle, initially in countries of Eastern Europe, have occurred in parallel with a growth in the rate of asthma and other allergic diseases This study was retrospective, based on reported co-morbidities, and a self-reported date of history of dengue fever in controls. The diagnosis of DHF was based on the information from review of cases investigated by the surveillance system. These potential limitations create methodological concerns. However, to be included in this analyses, available hospital data was reviewed by experts and found to satisfy the clinical and laboratory criteria described in A potential bias in this study is that dengue infection rates varied in Salvador and Fortaleza by skin color. However, there is good evidence that skin colour is not associated with dengue infection Subgroup analysis in blacks had not been planned. We hypothesized that hypertension was a risk and we knew of course that hypertension is more common in blacks. We did the subgroup analysis because hypertension risk was not found to be a risk factor in the role patient population. We suggest a cautious interpretation of this finding but urge that this be investigated in future studies.We did not present results separately for the two cities. This is appropriate as matching for cities would have controlled for any confounding; it would not have been appropriate if the associations between co-morbidities and DHF were different in the two cities. We did examine the magnitude of the associations in the two cities and judged them to be similar.The exclusion of individuals who were seronegative under the sample constraints described assured that all cases and controls, had dengue infection in the past. DENV1 and DENV2 have been circulating intensely in the two cities since the 1990s and the populations of these cities have high levels of antibodies against these serotypes This is the first case-control study to investigate the association between hospitalization with a diagnosis of DHF and evidence of diabetes and allergy, and hypertension and the results reported here are the initial evidence for this very important association. In dengue epidemics most dengue fever cases are seen in out-patients settings and then sent home, as there are too many for all to be hospitalized for observation, in spite of the potential for progression to DHF. If it were possible to identify those with higher risk of progression to DHF, and to keep them for observation, for to early detection of signs, symptoms and alterations in laboratory tests suggestive of DHF, this would enable timely and effective clinical management. Early intervention is such cases will reduce mortality substantially, since the case fatality rate of DHF in SE Asian patients is high (1–5%). We believe the evidence produced in this study when confirmed suggests that screening criteria might be used to identify adult patients at a greater risk of developing DHF with a recommendation that they remain under observation and monitoring in hospital. We also recommend further clinical studies to define new protocols on the evolution of dengue infections in patients with diabetes, allergies and hypertension (particularly with respect to drugs used) and appropriate medical management. Finally, cross immunologic pathophysiologic studies based on the associations between diabetes, allergy and high socioeconomic status and DHF, are urgently needed to investigate the intricate mechanism controlling severe forms of dengue.Checklist S1STROBE checklist.(0.20 MB RTF)Click here for additional data file.


We analyzed 314 subjects with African, Asian, Caucasian and Hispanic ancestries included 229 cases of primary open-angle glaucoma, 51 cases of juvenile-onset open-angle glaucoma, 33 cases of normal tension glaucoma, and 371 controls. Polymerase chain reaction-amplified OPTN coding exons were resequenced and case frequencies were compared to frequencies in controls matched for ancestry.Case-controlled study of OPTN allele frequencies for Caucasian and Asian populations that have been the subject of previous reports, we also present information for populations of Hispanic and black African ancestries.The E50K sequence variant was identified in one individual from Chile with normal tension glaucoma, and the 691_692insAG variant was found in one Ashkenazi Jewish individual from Russia. The R545Q variant was found in two Asian individuals with primary open-angle glaucoma; one of Filipino ancestry and one of Korean ancestry. In addition to presenting OPTN E50K mutation with glaucoma. After finding an additional 691_692insAG OPTN variant, we can still only conclude that this variant is rare. Combined analysis of our data with data from more than a dozen other studies indicates no association of R545Q with glaucoma in most populations. Those same studies disagree in their conclusions regarding the role of M98K in glaucoma. Our analysis of the combined data provides statistically significant evidence of association of M98K with normal tension glaucoma in Asian populations, but not in Caucasian populations; however, the validity of this conclusion is questionable because of large differences in allele frequencies between and within populations. It is currently not possible to tell how much of the underlying cause of the allele frequency difference is attributable to demographic, technical, or ascertainment differences among the studies.Our study contributes additional evidence to support the previously reported association of the  The optic neuropathy called glaucoma is the second most common cause of bilateral blindness in the world . The mosDuring the last decade, genetic mapping and cloning experiments have demonstrated that glaucoma has substantial genetic components . Among tMYOC) gene at the GLC1A locus are found in 2.6-4.3% of POAG cases [Mutations in the myocilin (AG cases . There hAG cases .optineurin (OPTN) gene, located within the GLC1E interval at 10p15-p14 [OPTN involvement in glaucoma presented three likely disease-causing variants designated E50K, 691_692insAG, and R545Q, and one proposed risk factor M98K [OPTN alleles with OAG, but others report no evidence of association of OAG with those same alleles [Rezaie et al.  describe alleles -24.OPTN mutation screening of 314 open-angle glaucoma patients who have either POAG, JOAG, or NTG, from populations of Caucasian, Asian, Hispanic, and African ancestry. We present case reports of individuals with E50K and 691_692insAG mutations and discuss findings from more than a dozen studies that have carried out OPTN mutation screening.In this paper, we present new data on our Informed consent was obtained from each participant according to a HIPAA-compliant study protocol approved by The University of Michigan Institutional Review Board for review of human subjects studies. Ophthalmologic examinations included slit-lamp biomicroscopy, optic disk examination, IOP by applanation, gonioscopy, and refraction. Individuals with known surgical or pharmacologic risk factors for glaucoma, such as steroid use, were excluded from this study.OAG was diagnosed based on the presence of open filtration angles, glaucomatous optic discs and glaucomatous visual field changes. Individuals with elevated IOP, greater than or equal to 22 mmHg, were considered to have POAG if they showed adult-onset at 35 years of age or older, and to have JOAG if they showed onset prior to 35 years of age. They were deemed to have NTG if their highest known IOP never exceeded 21 mmHg.OPTN was screened via sequencing of polymerase chain reaction (PCR) amplified DNA. Genomic DNA was extracted from peripheral blood samples using Puregene DNA Isolation kits  following the manufacurer's protocol. OPTN coding exons were amplified by PCR in a 20 μl reaction containing 50 ng of genomic DNA, 1.5 mmol/l MgCl2, 0.5 μmol/l of each primer, 0.125 mmol/l of each dNTP, and 0.5 units of Amplitaq Gold  in 1X final concentration of the PCR buffer. Primers used for exon amplification are listed in OPTN exons. When a sequence variant was detected in a patient, we screened for that specific mutation in the control population samples of the same ancestry.MYOC. PCR amplification of the three MYOC exons was conducted as described in reference [Individuals with E50K and 691_692insAG mutations who are presented in the case reports were screened for mutations in eference  with somPublished reports on the frequency of OAG mutations were compared using several different statistical tests. Because some studies contained expected frequencies of less than 5, Fisher's exact test was chosen to examine the 2x2 contingency tables of individual studies. In tandem with Fisher's exact test, odds ratios and 95% confidence intervals for the odds ratio were calculated. To estimate odds ratios for whole populations based on multiple studies, fixed effect estimates were calculated using a Mantel-Haenszel (MH) model . HomogenMYOC gene coding sequence and splice sites. Her family history showed evidence of autosomal dominant inheritance  in one copy of the OPTN gene. There were no other sequence variants in the coding sequence or splice sites of either OPTN or MYOC. Little family history information was available. She had a maternal grandfather affected by high myopia, but she didn't know of any other cases of glaucoma in her small family. Her only living relative, a reportedly unaffected son, declined to participate in the study.Case 2 was a female Russian Ashkenazi Jewish immigrant diagnosed with POAG at 80 years of age. Her ocular history was significant for high myopia  and myopic retinal degeneration in both eyes. The patient had a childhood history of measles, a disease that has been identified as a possible contributor to high myopia ,31. At tThe R545Q sequence variant was found in two individuals with OAG. One woman with Filipino ancestry had JOAG diagnosed at 24 years of age and had a maximum known pretreatment IOP of 50 mmHg. Her mother also had POAG and her brother is unaffected. She did not know the diagnostic status of the rest of her relatives in the Philippines. The second case, a Korean woman diagnosed at 55 years of age, had a maximum known IOP of 29 mmHg and an unknown family history of glaucoma.Among 36 OAG cases with the M98K mutation, the 26 for whom we have historical IOP data had known maximum IOPs between 16 mmHg and 55 mmHg (mean=29.6 mmHg). Out of the 283 OAG cases who lacked the M98K mutation, 253 had historical IOP data available, with the maximum recorded IOPs ranging from 14 mmHg up to 77 mmHg (mean=29.9 mmHg).Among the 314 OAG cases, we found a total of four (1.2%) individuals who possessed any of the three sequence variants reported by Rezaie and colleagues  to be diThe E50K mutation in Case 1 was the only instance of E50K among the 314 OAG cases  and in none of 371 controls (<2.7%), and was one of only 11 Hispanic cases screened , and was one of 217 Caucasian OAG cases screened 0.5%; . This waR545Q was present in two of the 314 OAG cases 0.6%; . It was The M98K sequence variant was found in JOAG, POAG, NTG, and control populations . We obseOPTN coding sequence polymorphisms, including L32L, T34T, L41L, E63E, A134A, and S321S, as well as previously reported intronic sequence variants [Screening identified two instances of E322K in both cases and controls - a change previously reported to be associated with glaucoma  Table 4Table 4. variants ,24,34,35R545Q was present in our Asian data set, but absent from the other three populations we screened. We found no significant differences in allele frequencies between cases and controls for R545Q. This agrees with many of the other published studies, although it should be noted that Mukhopadhyay et al.  did repoOur Asian data set is small, so we examined the possibility of pooling data from multiple studies. Because of observed variation in allele frequencies among studies  or African  ancestries than in Caucasian  or Hispanic  populations . Thus, aIf we consider specific defined subpopulations, where there should be less concern about ancestry serving as a confounding variable, then we are left with concerns about differences observed not just between but also within populations. When we compared the different Asian studies using odds ratios , the aggThe results of the Woolf test for heterogeneity indicated that there was something noncomparable about the M98K findings from a number of the studies that reported results for the same populations . In the The case versus control difference for the Hispanic data are also intriguing, with M98K case values of 1/11 (9.1%) and control values of 1/50 (2.0%). Our small Hispanic data set was not well-powered for statistical testing, but this represented an initial view of a population under represented in previous studies . Given tOPTN variants previously reported to be disease-causing variants-E50K, 691_692insAG, and R545Q, as well as the M98K variant previously reported as a risk factor [In our study of 314 individuals with OAG, we found 42 individuals with sequence variants predicted to alter the protein coding sequence. This included three OPTN defects were originally reported in a population of primarily NTG cases, we found this variant in an individual with modestly elevated IOP (22 mmHg). The shift in the reading frame that it causes and the fact that it is seen among cases but not controls suggests that it could be a causative variant. However, if we combine data from all studies, we see it in 2/3677 cases (0.0005%) in the studies that used protocols that would have detected it . An alternative confounding factor could be the result of the different screening techniques applied (There are a number of confounding factors that might contribute to the observed variability of allele frequency between Asian populations. Differential allele frequencies within a population could result from founder effects. At this point, there is not enough information available regarding origins of the different subpopulations  to allow applied ; howeverAn alternative approach to evaluation of whether the M98K allele is involved in glaucoma is through the study of cosegregation in families. Wiggs et al.  reportedOne alternative explanation for why some studies find association, yet others do not, might be that there is a valid statistical difference between the case and control populations but that the M98K allele is actually associated with some other variable that differs between cases and controls, or has been excluded from cases but not controls. An obvious example of this would be IOP. The Rezaie et al. study  offered -7. The other studies that found any support for M98K association with glaucoma found only weak evidence of this association. It remains unclear what the differences are between the studies that could account for the differences in study outcome. One key issue for M98K appears to be the great variability of allele frequency reported in different studies and different populations. This would be a problem if the case population in the Rezaie et al. study [The original report by Rezaie provided apparently compelling statistical evidence that M98K is a glaucoma risk factor with a p value of 2.18x10Thus the findings on M98K are currently contradictory, with some studies finding association and other studies finding no support for association, and with the differences in study outcome not assorting according to population or technology used. Because there are such substantial differences in allele frequencies between the different studies and between and within populations, it is likely that a final resolution of this question will require the following: The screening to take place by technologies selected for precision rather than high throughput; the study be adequately powered; matching of cases and controls for ancestry be highly rigorous and matched for subpopulations rather than simply matching for one of a handful of racial or ethnic categories; inclusion and exclusion criteria be carefully defined, that tests for association with associated variables such as IOP be carried out in addition to tests for association with the primary glaucoma status variable; and population substructure analysis be included in the analysis to help deal with apparent differences within populations that can be difficult to control.OPTN E50K with glaucoma, and reported an additional instance of the 691_692insAG sequence variant. We have also provided new information on OPTN in populations of African and Hispanic ancestry. Evaluation of data from more than a dozen studies indicated no association of R545Q with glaucoma in most populations. Combined analysis of more than a dozen studies suggests that M98K is associated with NTG in Asian, but not Caucasian study populations, but these results must be interpreted with great caution because of the large differences in allele frequencies between and within populations.This study has contibuted additional evidence of association of


Risk for complex disease is thought to be controlled by multiple genetic risk factors, each with small individual effects. Meta-analyses of several independent studies may be helpful to increase the ability to detect association when effect sizes are modest. Although many software options are available for meta-analysis of genetic case-control data, no currently available software implements the method described by Kazeem and Farrall (2005), which combines data from independent family-based and case-control studies..I introduce the package catmap for the R statistical computing environment that implements fixed- and random-effects pooled estimates for case-control and transmission disequilibrium methods, allowing for the use of genetic association data across study types. In addition, catmap may be used to create forest and funnel plots and to perform sensitivity analysis and cumulative meta-analysis. catmap is available from the Comprehensive R Archive Network catmap allows researchers to synthesize data to assess evidence for association in studies of genetic polymorphisms, facilitating the use of pooled data analyses which may increase power to detect moderate genetic associations. Two study designs are commonly employed in genetic association studies: a case-control and a family-based approach. The case-control design compares frequencies of alleles carried among cases with a disease and among controls that are free of disease. The family-based design compares the frequency of alleles transmitted to an affected offspring by their parents with alleles carried by the parents but not passed to the offspring; this type of statistical analysis is often called a transmission disequilibrium test (TDT). Complex diseases are likely to be under the influence of several genetic risk factors; therefore, the contribution of a single gene to risk of disease is expected to be modest. Meta-analysis allows for the pooling of independent studies that examine similar hypotheses; for example, that a particular allele at a SNP is associated with disease status, and thus may improve power to detect moderate effect sizes. Although a few methods have been developed to combine family-based data with data from unrelated controls and/or unrelated cases obtained by the same study -10, mostwi = 1/σi2), which gives increased weight to larger studies . The pooled estimate of the logarithm of the odds ratios using fixed effects methods (ORFE) is given by[Fixed-effect estimates are as described by Kazeem and Farrall . First,  given by:with associated variance estimate of:wi are the study-specific weights as described above. In the presence of heterogeneity of genetic effects random-effects estimates of the pooled OR and variance may be more appropriate. Random-effects models do not assume that a common genetic effect exists across all samples. Following DerSimonian and Laird [τ2, as:where K is the number of studies to be pooled, and the nd Laird ,13, the χ2 statistic  and the random-effects pooled estimate of the logarithm of the odds ratio (ORRE) can be written as:Where Q is the heterogeneity tic (see  for reviRE) is simply 1/(Σri)1/2.and the standard error of the random-effects pooled ln should be used as input to catmap. catmap calculates fixed- and random-effects estimates, a χ2 test for heterogeneity and associated p-values and must be used to create a catmap object for use in downstream functions. To create a forest plot using either the pooled fixed- or random-effects OR and 95% CI the function catmap.forest is used. catmap.sense calculates leave-one-out sensitivity analyses using either fixed- or random-effects estimates and creates a Portable Document Format (PDF) plot of the estimate of the pooled OR and 95% CIs with the removed study listed on the y-axis  the number of alleles transmitted to affected offspring, the number of alleles not transmitted to affected offspring (both referring to family-based studies), the number of risk alleles in cases, the number of risk alleles observed in controls, the number of non-risk alleles observed in cases and the number of non-risk alleles observed in controls (latter 4 columns referring to case-control studies) must be specified. In the case of a family-based study, the χ2 indicates significant between-study differences in effect sizes, although when evidence for heterogeneity exists the pooling of data may not be indicated. Since two types of study design (case-control and family-based) are common in statistical genetics, methods and freely-available software that can combine estimates from both designs should prove useful to applied researchers.Pooling studies of genetic polymorphisms data via meta-analysis may improve the ability of researchers to detect modest association signals. Since case-control studies are not robust to spurious effects caused by confounding via population stratification, before combining results from case-control studies researchers should assess evidence for substructure in individual studies and also examine the similarity of effect sizes and allele frequencies across study type and population, along with the formal test of heterogeneity of genetic effect implemented in catmap. catmap implements a random-effects estimate of the pooled odds ratio, which assumes a Normal distribution of genetic effects across studies instead of a single genetic effect, which may be preferred when combining studies across sub-groups or when the heterogeneity Project name: catmapProject home page: Contributed package at .Operating systems: MS Windows, Linux, MacProgramming language: ROther requirements: R 2.4 or higherLicense: GPLAny restrictions to use by non-academics: noneKKN conceived of the random effects method, created the software and wrote the manuscript.


A case-control study in Somerset and east Devon was undertaken to investigate possible risk factors for prostatic cancer. A total of 159 cases, diagnosed at Taunton. Yeovil and Exeter hospitals between May 1989 and May 1991, were identified prospectively and interviewed with a structured questionnaire. A total of 161 men diagnosed with benign prostatic hypertrophy and 164 non-urological hospital controls were given identical questionnaires. The questionnaire covered a wide range of factors identified from previous studies, but the central hypotheses for this study related to diet (fat and green vegetables), sexual activity and farming as an occupation. This study found no association between farming and risk of prostatic cancer , nor with sexual activity as measured by number of sexual partners (chi-squared test for trend P = 0.52). A history of sexually transmitted disease was not significantly associated with prostatic cancer, but the numbers involved were very small and the odds ratio of 2.06 (0.38-11.2) is consistent with the hypothesis. A range of questions aimed at eliciting dietary fat intake produced no significant associations, although meat consumption showed increasing risk with increasing consumption (test for trend P = 0.005). Increased consumption of leafy green vegetables was associated with lower risk, but not significantly so (test for trend P = 0.16). As expected with so many factors investigated, some statistically significant associations were found, although these can only be viewed as hypothesis generating in this context. These included apparent protective effects of circumcision and high fish consumption.


Dear Editor,The peer review process strives to ensure accuracy of published research. However, passing muster with reviewers  does not in itself legitimize an article’s conclusions; ultimately it is the reader’s responsibility to scrutinize the data and use other available information before adopting recommendations. This is especially true of research that (rightly) questions existing dogma. Such investigations have the capability of initiating much needed cost-effective changes, but, unfortunately, also carry the potential for dire consequences. A case in point is an article pertaining to endophthalmitis in India that was recently published in an overseas journal.The occurrence of post-cataract endophthalmitis in India has been reported to be 0.6%. The publThe system of critical appraisal that I have used and taught in journal clubs was devised by Riegelmann, supplemented by other texts.–5 RiegleIt is impossible to provide a full critique of the article in this brief communication, but in order to illustrate the process I will apply the relevant parts of SAARIE and incorporate important background knowledge of cataract surgery in India to re-analyze the data and conclusions.One of the questions asked under the heading Study, (S in SAARIE), is whether the study design was appropriate for the question being asked. We know that incidence should be determined by a prospective study, not a retrospective one. Incidence calculated from a retrospective study should be viewed with caution.Assignment, the first A in SAARIE also highlights that cases were obtained retrospectively. Under this heading we also look for confounding. A confounder has several attributes: It is a factor extraneous to the question being asked that can affect the outcome, is different between the analyzed groups and is not in the causal pathway. “Charity” patients are extraneous to the question being asked but, as we will see, they can affect the outcome and are unequally distributed between the analyzed groups. We must consider “charity” a potential confounding factor.Nocardia, quite different  from the spectrum reported from other hospitals, and we begin to suspect that the commoner organisms and early cases were likely missed.Equally important is the Assessment of outcomes (the second A in SAARIE). The selected outcome measure must be appropriate, accurate, precise and should be evaluated in a masked manner with adequate follow-up. The detection of endophthalmitis is certainly an appropriate outcome measure but the article did not adequately define endophthalmitis or the details of how it was diagnosed; nor did it provide data for the accuracy and precision of diagnosis. The “clinical impression” of doctors at various levels of training rather than a precise definition and a clear description of methods used for the diagnosis is not acceptable. We also need to keep in mind that some of the diagnoses were made in the environs of cataract screening camps in remote areas; anyone who has attended such camps knows the attendant diagnostic limitations. Add to this the fact that the commonest organism grown was While on outcome measures, we also look at completeness of follow-up and build this into our analysis. It is a little difficult to reconcile the follow-up periods with the article submission date, but we are more concerned about the loss to follow-up. The loss to follow-up was 6% amongst the paying patients and 16% in the “charity” group. While this does not seem too high, in the presence of a low rate of the event in question, such a loss to follow-up can change the results considerably and deny robust conclusions. One acceThe informed reader would realize at this point that given the fatal flaws in study design and assessment of the outcome, the results cannot be applied. I will however continue the appraisal as there are other important lessons to be learnt.We next look at the Results (the R in SAARIE). The authors claim no difference between charity and paying patients, discuss a higher rate for surgeons in training (SIT) versus full time surgeons (FTS), and report a higher endophthalmitis for manual small incision surgery (MSICS). A closer look at their Tables 1and 2 tells a different story: “charity” is a confounding factor. Using charity cases as an exposure, the odds ratio for being a charity patient amongst those with endophthalmitis is 4.6, confidence interval (CI) 1.6 – 15. The authors feel the MSICS is the major culprit. But even if we examine MSICS alone, the odds of charity in endophthalmitis cases are 3.6 (CI 0.5 -26).Their Table 1 shows us that FTS performed a total of 21284 MSICS.[The Interpretation (I in SAARIE) of the study results requires insight into the cataract surgical scene in India. MSICS (versus phaco) and operations by trainee surgeons (versus FTS) are proposed risk factors for endophthalmitis, but the confounder of “charity”, or something associated with it is the true risk factor.The data from the study strongly suggest that there is a difference in the treatment of paying and charity cases.That pre- and postoperative examination as well as surgical protocols differ between paying and “charity” cases is no secret to any Indian ophthalmologist; some hospitals even have a policy of separate outpatient and operating rooms (ORs) for charity patients. It does not take a formal Bayesian analysis to combine such prior knowledge with the data to determine what is going on.nocardia in the soil have been provided as explanation for some of the cases.[The authors claim a low endophthalmitis rate despite operating on patients from the lower socioeconomic strata and despite a large number of trainee surgeons. Poor hygiene, and, in an earlier publication the presence of he cases. If poor SIT are also considered part of the problem. However, if SIT are properly supervised and the protocols are followed, outcomes, especially endophthalmitis, should be no different from FTS. That has to be the basis of using humans for safe training. The commIt looks like the results cannot really be Extrapolated (E in SAARIE) to any setting. The basic premise of the shortcut protocols too is dubious: the authors feel that stringent sterilization and OR protocols were devised with other specialties in mind and do not have relevance to ophthalmology. Is a lens implant to be treated with less rigor than a bone marrow transplant or a hip replacement? And even if the fatal flaws discussed were not present, the data do not come anywhere close to suggesting that existing rigorous protocols be abandoned.Use of the SAARIE also allows us to make suggestions for improvement and further study. The Aravind Eye Care System comprises high-volume hospitals that together can provide crucial information to change ophthalmic surgical protocols worldwide. I would urge them to consider an appropriately designed prospective study that addresses the limitations raised. And considering the enormity of the proposed change and the required “buy in”, I would also suggest that any such study utilize external input into planning and consider external validation of outcomes. Their quality assurance process could take cognizance of the data and try to eliminate the causes that make “charity” a risk.Ophthalmic information is increasing exponentially and it is easy to be misled; critical appraisal skills provide a defense to some of the ill effects of information overload. I hope I have made a case for developing critical appraisal skills; I sincerely believe it should be made an integral part of our residency and fellowship training process.


This study aimed to test the feasibility of a programme of semen collection and cryopreservation in Griffon vultures. Four wild-caught individuals kept in captivity because of unrecoverable traumas were used. Semen collection attempts were made twice a week during three consecutive reproductive seasons (December – March) using the abdominal massage method. Ejaculation was successfully induced between late January and late February. Semen collection efficiency was rather low (27.9%) and it did not vary among individuals (p > 0.05). No differences were found in ejaculate volumes (12.5 +/- 9.1 μl), spermatozoa concentration (28.4 +/- 30.9 million cells/ml) and viability (61.3 +/- 13.9%) among the 4 vultures. ATP values differed among the four vultures (p < 0.001); B showed higher nucleotide concentration than both C and D, while it did not differ form A, whose values were higher compared with D. After freezing and thawing, semen in vitro viability, DNA integrity and ATP intracellular concentration were determined. Spermatozoa viability after thawing did not differ among the four individuals , but it decreased significantly compared to fresh semen (p < 0.05). During 4 hrs in vitro culture, spermatozoa collected from B maintained over time a higher viability in vitro when compared to A, C and D. As evaluated by the comet assay method, DNA fragmentation after freezing and thawing did not differ in the 4 vultures. ATP concentration in frozen/thawed semen was significantly lower than in fresh semen (p < 0.0001). This study indicates that semen cryopreservation can be considered as a useful tool in the conservation of Griffon vulture genetic resources, but further studies are needed to optimize this technique. Establishing a genome resource bank, along with assisted breeding techniques, has the potential to preserve genetic diversity of many endangered species managed ex situ . Frozen Gallus gallus has recently been reported , the Am.9% was l× 106/ml . Total sSturnus vulgaris) . Differulgaris) ; (2) abdulgaris) ,37; (3) ulgaris) ; (4) cooulgaris) ; (5) useulgaris) .All of these techniques have limitations. The principal side effects of the abdominal massage method is that it is a stressful procedure, since it involves catching and handling of the birds, and that it stimulates urination, with consequent contamination of the ejaculates ,39. We hNevertheless we choose this method because it was the less invasive for not imprinted birds and it had been already tested on vultures . Better Gazella cuvieri, the individual's coefficient of inbreeding correlated negatively with many parameters of semen quality, including ejaculate volume . Two biDNA fragmentation after freezing and thawing did non differ in the 4 vultures as evaluated by the comet assay method. The lack of repair mechanisms in sperm makes DNA damage irreversible. Griffon vultures frozen/thawed spermatozoa do not appear to be particularly susceptible to DNA fragmentation during cryopreservation since the mean scored parameters are similar to those recorded in turkey spermatozoa kept 2 hrs at 4–7°C . Since cGrus leucogeranus) [The extent of ATP loss in Griffon vulture spermatozoa was severe after cryopreservation. This result agrees with data reported for rooster  and crangeranus) . Given tgeranus) . As a cageranus) ,58. Studgeranus) . These rIn conclusion, this study provides original information on Griffon vulture semen characteristic and cryotolerance, and points out the many difficulties that still prevent the widespread use of semen cryopreservation in the conservation of genetic resources in wild birds. Other techniques, such as the long-term preservation of primordial germ cells , the cryThe authors declare that they have no competing interests.MM performed the semen collection and analysis, and helped drafting the manuscript. FB participated in the design of the study, carried out experimental analysis, performed the statistical analysis and drafted the manuscript. GGL participated in the design of the study and performed the statistical analysis. VS performed the DNA analysis for the individuation of the sex of the animals and participated in semen analysis. VP helped in performing the DNA and ATP analyses. ML, SS and AR helped in sample collection and in drafting of the manuscript and participated in the design of the study. AZ and CC performed the ATP analysis. MM conceptualised the idea, helped in drafting the manuscript and revising it critically for important intellectual content. SN conceived of the study, participated in its design and coordination and helped to draft the manuscript. All co-authors provided inputs during final manuscript preparation. All authors read and approved the final manuscript.