TLR4) induce an aberrant immune response to indigenous intestinal flora, which might favor IBD development. In this study, we aimed to determine whether TLR4 gene was associated with Crohn’s disease (CD) and ulcerative colitis (UC) among Moroccan patients, and evaluated its correlation with clinical manifestation of the disease.The pathogenesis of inflammatory bowel disease (IBD) involves interactions between the host genetic susceptibility, intestinal microflora and mucosal immune responses through the pattern recognition receptor. Polymorphisms in toll-like receptor 4 (TLR4 polymorphisms: Asp299Gly and Thr399Ile were genotyped by polymerase chain reaction-restriction fragment length polymorphism. PCR products were cleaved with Nco I for the Asp299Gly polymorphism and Hinf I for the Thr399Ile polymorphism. Meta-analysis was performed to test the association of 299Gly and 399Ileu carriage with CD, UC and the overall IBD risk.The study population comprised 117 patients with IBD and 112 healthy unrelated blood donors. Our study revealed that the frequency of Asp299Gly and Thr399Ile did not differ significantly between patients and controls in the Moroccan population. However, meta-analysis demonstrated significantly higher frequencies of both Asp299Gly and Thr399Ile SNPs in IBD and CD and for 399Ileu carriage in UC patients.TLR4 polymorphisms confer a significant increased risk for the overall IBD development.The meta-analysis provides evidence that  Inflammatory bowel disease (IBD) is an idiopathic and chronic multifactorial disease of the gastrointestinal tract. Although the precise etiology of IBD is unclear, several factors that play a crucial role in disease pathogenesis such as commensal bacterial flora and genes related to the host immune response have been identified ,2.Toll-like receptors are pattern recognition receptors through which host recognizes microbial conserved molecular motifs that are broadly shared by pathogens, therefore they are very important for the regulation of mucosal innate immune responses to intestinal microbes. Perturbations in individual TLR biological signaling can prime to a number of different outcomes and elucidate a system of regulation within the intestine in which each TLR plays a largely non-redundant role in mucosal immunity.TLR4 gene, the first mammalian TLR identified is located on the long arm of human chromosome 9q32-33 [ 9q32-33 .TLR4 is the major transducer of lipopolysaccharide (LPS) and binds specifically lipid A moiety. Signal transduction through TLR4 in combination with CD14, and MD-2 leads to activation of the nuclear factor-κB (NF-κB) system through the MyD88-dependent and MyD88-independent pathways and subsequent expression of inflammatory genes encoding cytokines and cell conjugation molecules as part of host defense mechanisms -9.Under healthy conditions TLR4 is only minimally expressed in lamina propria mononuclear cells (LPMNCs) and intestinal epithelial cells which are partly tolerant to LPS, thus preventing an exaggerated immune response mediated by the large number of bacteria in the intestinal lumen and maintaining a basal state of activation ,11.TLR4 (Asp299Gly and Thr399Ile) have been described in humans. Individuals heterozygous for these mutations have a blunted response to inhaled LPS [However, TLR4 expression is upregulated in human IBD colitis, maximizing responsiveness to the environment and reflecting an aberrant state of activation -15. Highaled LPS . These pTLR4 determine susceptibility to IBD in Moroccan patients and assessed their influence on phenotype expression.Thereby, we sought to investigate whether Asp299Gly and Thr399Ile single nucleotide polymorphisms of the gene encoding the Enrolled in this study were 117 IBD Moroccan patients  and 112 healthy unrelated blood donors. The diagnosis of CD or UC was established according to conventional clinical, endoscopic, radiological and histological criteria as previously reported ,19. CD wThe case report form included questions on disease phenotype and location, age at diagnosis, toxic behavior and other clinical features. The ethics committee of the Faculty of Medicine and Pharmacy of Casablanca approved the study and a written informed consent was obtained from all human subjects.TLR4, were analyzed: the Asp299Gly (896A/G), rs4986790 and the Thr399Ile (1196C/T), rs4986791.Genomic DNA was extracted from peripheral blood leukocytes using the salting out procedure. Two single nucleotide variations, corresponding to two amino acid polymorphisms for Typing of the polymorphisms was performed using polymerase chain reaction (PCR) restriction fragment length polymorphism analysis (RFLP).F: (5′- AGCATACTTAGACTACTACCTCCATG-3′),TLR4Asp299GlyR: (5′- GAGAGATTTGAGTTTCAATGTGGG-3′) for And F: (5′-GGTTGCTGTTCTCAAAGTGATTTTGGGAGAA-3′),TLR4Thr399Ile.R:(5′-GGAAATCCAGATGTTCTAGTTGTTCTAAGCC-3′) for Upstream and downstream primers used for the PCR amplification were:Reactions were performed in a 25 μl volume containing 200 μM of each dNTP , 0.2 μM of each of the forward and reverse primers (0.5 μl of each 10 μM primers), 2 mM MgCl2  and 1 U of Taq DNA polymerase (1 μl of 1U/μl enzyme), 1× PCR buffer (2.5 μl of 10× PCR buffer).PCR conditions comprised 5 min at 95°C then 35 cycles of denaturing were performed at 95°C for 30 s, annealing at 55°C (Asp299Gly) and at 53°C (Thr399Ile) for 1 min, 72°C for 30 s. A final extension phase of 72°C for 10 minutes was used.PCR products were cleaved overnight at 37°C with Nco I for Asp299Gly polymorphism and HinfI for Thr399Ile polymorphism (Biolabs). The digests were run on a 3% agarose gel and visualized under UV light using ethidium bromide.The mutant alleles (GG)/(TT) contained an Nco I/ Hinf I restriction site for the Asp299Gly/Thr399Ile polymorphisms respectively, allowing RFLP analysis of the digested products. Digestion at the Nco I site yields fragments of 168 and 20 bp, the one at Hinf I site yields fragments of 98 and 26 bp. The wild-type allele for both polymorphisms remained uncut.The data were analyzed with MedCalc 11.6. Chi-square test was used to compare the allele and genotype frequencies between disease and control groups. The Fisher’s exact test was used when appropriate. The observed genotype frequencies were compared with the predicted frequencies by the Hardy–Weinberg equilibrium.P values less than 0.05 were considered significant in disease risk association tests. The χ2 test or Fisher test was used to correlate the TLR4 polymorphisms and clinical parameters. The Bonferroni correction method was applied for correction for multiple testing in sub-phenotype analysis; The phenotype genotype correlation was considered statistically significant if the p value was less than 0.005 for CD and 0.007 for UC. According to Power Calculator for Genetic Studies 2006 software (http://www.sph.umich.edu/csg/abecasis/CaTS/), this study had 15% of power to detect an OR of 1.5.The average age was determined by the rank sum test. Associations between genotypes and risk of IBD were estimated by calculating odds ratio (OR) with confidence interval of 95% (CI). Genetic association studies were included in our meta-analysis if they met the following criteria:TLR4 Asp299Gly, Thr399Ile polymorphisms and IBD, (b) A case–control study design, (c) The study reported sufficient data to calculate allele frequencies, odds ratios and confidence intervals of cases and controls for carriage of the TLR4 299Gly and 399Ile alleles.(a) Studies that evaluated the association between the TLR4 Asp299Gly and Thr399Ile genotypes.While major exclusion criteria were: (a) case-only study and review articles (b) absence of the mutant allele in both cases and controls, (c) studies without the raw data of the Asp299Gly polymorphism: According to the inclusion criteria, twenty studies were retrieved in CD meta-analysis  and 95% confidence interval (95% CI).The risk of IBD associated with the 2 statistics was used to quantify the between-study heterogeneity effect. When a significant Q test  indicated heterogeneity across studies, data were recombined using a random-effects model to estimate common ORs. The meta-analyses were conducted by Review Manager 5.0 and MedCalc bvba 12.3.0 softwares.The meta-ORs were estimated using a fixed-effects model with the wild-type allele as reference group. Genetic heterogeneity was tested by Cochran’s (Q) test, ITwenty-four case–control studies were identified through the literature search.TLR4Asp299Gly and Thr399Ile polymorphisms.Hundred and seventeen patients with IBD  and 112 control subjects from the general population were genotyped for the presence of TLR4Asp299Gly and Thr399Ile polymorphisms in CD patients  and healthy controls  were in Hardy-Weinberg equilibrium. In patients with UC, genotype and allele frequencies distributions for Asp299Gly polymorphism  were in Hardy-Weinberg equilibrium but not for Th399ILeu polymorphism .The average age of CD, UC patients and controls was 27.6 ± 2.3, 40 ± 5.0 and 31.3 ± 2.1 years respectively. The distributions of genotype and allele frequencies of both TLR4 variants in IBD overall and in CD and UC in particular, the distribution of TLR4 polymorphic alleles was assessed. Genotype and allele frequencies are given in Table TLR4 polymorphic alleles was observed in only 33% of controls (3 out of 9), 33% in UC (2 out of 6) and 60% in CD (6 out of 10).In order to study associations of TLR4 Asp299Gly variant allele and CD risk in a total of 5338 cases and 5076 controls   and UC .Meta-analysis of our dataset with the published studies showed a significant association between 2 = 73.6%).Combining Asp299Gly results for CD and UC (6115 cases and 3622 controls), an overall significant increased risk for IBD was observed, OR = 1.15, 95% CI = 1.03-1.30; P = 0.015  for a total of 3392 cases and 1773 controls , UC  and IBD .In the present meta-analysis, we did not observed heterogeneity between studies for TLR4 polymorphisms are shown in  with IBD and its clinical manifestation. Attention was focused on co-segregating SNPs located in exon 3 of TLR4 causing amino acid exchanges at positions 299 (Asp299Gly) and 399 (Thr399Ile) which are located in the extracellular domain of the receptor [TLR4 Asp299Gly with CD was first reported by Braat et al. [TLR4 gene with IBD and its clinical complications, we investigated for the first time the potential influence of TLR4 SNPs in the susceptibility to IBD in a cohort of Moroccan patients. However, the statistical power was very low and could be considered a limitation in this study. Our study showed that the GG genotype was not found in both CD and UC patients. No significant differences were observed in allele frequencies of the TLR4Asp299Gly among patients and controls. In addition, although slightly increased frequencies of the mutant alleles were encountered, we were not able to identify a significant difference in allele distributions of the TLR4Thr399Ile in our case–control study. In line with our results, a Tunisian study that genotyped 90 patients with CD and 80 healthy individuals for the Asp299Gly and Thr399Ile polymorphisms, reported the absence of association between CD and TLR4 gene in a north African population [Given the evidence that an altered innate immune response and chronic inflammation are implicated in IBD pathogenesis, genetic influence of pattern recognition receptors was clearly suggested as a trigger of CD and UC. Several efforts were undertaken to demonstrate associations of the human receptor ,48. Assot et al.  subsequepulation . AlthougTLR4 mutant alleles are known to be inherited in the form of Asp299Gly/Thr399Ile haplotype [Being in linkage disequilibrium, aplotype . In a Geaplotype . These oTLR4 allele frequency between IBD patients and controls was observed in Hungarian [TLR4 and CD14 variants in Scottish and Irish CD patients [TLR4 (p.D299G) variant in Germans and Hungarians [TLR4 was linked to an increased IBD (CD or UC) risk in many other diverse investigations. Significant associations were found in patients drawn from Belgian [Results on the relationship of Asp299Gly SNP alone or in combination with Thr399Ile with IBD are inconsistent between studies. No difference in ungarian , Saudi Aungarian , Southerungarian , New Zeaungarian  and EC-Iungarian  study grpatients . Moreovengarians . Interesngarians , Korean ngarians , Chinesengarians  and Zhuangarians . TLR4 wa Belgian , German  Belgian ,33, Gree Belgian ,46 and D Belgian  populati Belgian ,42,50. TA correlation between Asp299Gly variant and an increased disease risk is also reported for CD and IBD but not regarding UC, which is in line with de Jager et al. findings . This inTLR4 gene SNPs varies between populations [To date it is well known that the frequency of the investigated ulations ,31. Overulations . Our resulations .In view of the role of potential confounders related to the present study and to discrepant results between populations, it is likely that the contribution of different sample size, selection bias, phenotypic heterogeneity and population stratification in case control studies can’t be ruled out. These data demonstrate further the real difficulties in candidate gene analysis in complex diseases. Moreover, given that IBD is a polygenic disease it is provided that association studies will reveal various sets of susceptible genes. Therefore, further large-scale studies are required to obtain a clear insight into the impact of the pattern recognition receptors in the pathophysiological and immunogenetic aspects of IBD and to explore the contribution of other genes involved in various processes.TLR4 gene are not associated with IBD in a sample of Moroccan patients. However, our dataset contributed to the significant association observed in TLR4 meta-analysis.In the present study, we have demonstrated that the common mutations in the TLR4 gene polymorphisms have ethnic differences. Our data suggests that other genetic and environmental factors may play a role in IBD susceptibility and behavior in this population. However, because of the relatively small sample size, additional well-powered studies are needed to confirm our findings.It is likely that the distribution of


Fusobacterium, and Porphyromonas with colorectal cancer detected by 16S rRNA were reproduced by metagenomics, whereas higher relative abundance of Clostridia in cancer cases based on 16S rRNA was merely borderline based on metagenomics. This demonstrated that within the same sample set, most, but not all taxonomic associations were seen with both methods. Considering significant cancer associations with the relative abundance of genes, modules, and pathways in a recently published French metagenomics dataset, statistically significant associations in the Washington, DC population were detected for four out of 10 genes, three out of nine modules, and seven out of 17 pathways. In total, colorectal cancer status in the Washington, DC study was associated with 39% of the metagenome-predicted genes, modules, and pathways identified in the French study. More within and between population comparisons are needed to identify sources of variation and disease associations that can be reproduced despite these variations. Future studies should have larger sample sizes or pool data across studies to have sufficient power to detect associations that are reproducible and significant after correction for multiple testing.Accumulating evidence indicates that the gut microbiota affects colorectal cancer development, but previous studies have varied in population, technical methods, and associations with cancer. Understanding these variations is needed for comparisons and for potential pooling across studies. Therefore, we performed whole-genome shotgun sequencing on fecal samples from 52 pre-treatment colorectal cancer cases and 52 matched controls from Washington, DC. We compared findings from a previously published 16S rRNA study to the metagenomics-derived taxonomy within the same population. In addition, metagenome-predicted genes, modules, and pathways in the Washington, DC cases and controls were compared to cases and controls recruited in France whose specimens were processed using the same platform. Associations between the presence of fecal Fusobacteria,  Fusobacterium and Porphyromonas [The human microbiome is the subject of a growing area of research since it is likely related to human health and disease. There is accumulating evidence that the microbiome plays a role in colorectal cancer (CRC) development or progression, potentially through inflammatory pathways or carcinogenic microbial metabolites , and micyromonas . Of the yromonas , 5, 7, 9yromonas , 6, 8). yromonas .We performed shotgun metagenomic sequencing of fecal samples from a CRC case-control study conducted in the 1980s in Washington, DC that were previously analyzed by 16S rRNA gene sequencing . By subj2 or ≥ 20 kg/m2). Associations in the WGSS DC analysis were compared to those in the previous 16S rRNA gene sequencing study (population 16S DC), which included 47 CRC cases and 94 control subjects from the same parent study. All 47 CRC cases from 16S DC were included in the WGSS DC and the 52 controls in WGSS DC were included in the 94 controls from 16S DC. Participants provided written informed consent and this study was approved by the Office of Human Subjects Research at the National Institutes of Health.The fecal samples were collected in a CRC case-control study that has been previously described in detail  and the We included data from a previously published study (population F) as an independent validation set . In brieWe also included publically available shotgun metagenomic data from 292 MetaHIT participants , 13 and The freeze-dried fecal samples from WGSS DC were defrosted, resuspended in phosphate-buffered saline, and an aliquot was shipped to the Genomics Core Facility, European Molecular Biology Laboratory in Heidelberg, Germany on dry ice. The methods for DNA extraction, library preparation, and whole-genome shotgun sequencing have been described in detail  and wereThe general strategy for the bioinformatic processing of the whole-genome sequencing data has been previously described in detail  and was We compared Shannon diversity, richness, and evenness for population WGSS DC, population F, MetaHIT, and HMP Phase I samples and tested case-control differences in population WGSS DC and population F using the Kruskal Wallis test. Then, for both the primary study population (population WGSS DC: 52 cases vs 52 controls) and the independent validation population (population F: 53 cases vs 88 controls), we tested for the associations between case/control status and both the relative abundance and presence/absence of the different taxonomic levels and gene categories . A logistic regression model with adjustment for age, sex, and body mass index (BMI) was used and the p values were calculated based on the Wald test . Three CCharacteristics of the 52 CRC cases and 52 controls from population WGSS DC are presented in Fusobacterium (p = 0.006) and Porphyromonas (p = 0.032) with CRC case status. The association between Atopobium and CRC from the 16S DC was not reproduced in the WGSS , the presence of 4 taxa and the relative abundance of 3 taxa were significantly associated with CRC case status with false discovery rate-adjusted p values less than 0.05. As seen in the WGSS . As seenthe WGSS .In population WGSS DC, there were no significant differences between CRC cases and controls for Shannon diversity, richness, or evenness based on mOTUs, although in general the controls had slightly higher alpha diversity compared to cases . ShannonCRC case status in population F  was stroIn contrast to the global assessment , when weFusobacterium genus among CRC cases. One large difference between the two studies was the sensitivity for detecting taxa. For example, the Fusobacteria phyla was detected in 36.2% of the cases and 16.0% of the controls in the 16S rRNA gene study, but using whole-genome shotgun metagenomics, Fusobacteria was detected in 76.9% of the cases and 48.1% of the controls. It is unclear what may cause the differences between the 16S rRNA and WGSS results, but it may be due to the 16S rRNA gene variable region sequenced, the depth of sequencing, the bioinformatic assignment of taxonomy, or technical differences. These variations in detecting the presence and relative abundance of taxa demonstrate an important difference when comparing 16S rRNA sequencing to whole-genome shotgun metagenomic studies and should be studied in more detail in the future.This study had two primary aims: 1) to compare the previously observed 16S rRNA gene associations with data from whole-genome shotgun metagenomic sequencing; and 2) to investigate potential microbial gene-level associations with CRC in different populations. For the first aim, the metagenomics approach reproduced some of the previously observed associations in the 16S rRNA gene analysis, most notably higher likelihood of detecting taxa in the Fusobacteria phylum and For our second aim, the WGSS DC did reproduce some of the specific, statistically significant genes, modules, and pathways detected in population F with CRC case status . Two relOur reproducibility of statistically significant associations from a previous study  providesFusobacterium compared to controls [Porphyromonas in CRC cases compared to controls [Other previous studies have investigated associations between the fecal microbiome and CRC . Similarcontrols , 5–7, 9,controls , 5, 7. Icontrols  similar controls . In summThe current study is not without limitations. First, all of the fecal samples were collected cross-sectionally, so it is not possible to determine if the microbial changes occurred prior to cancer development or if they were due to the development of cancer. In addition, this study had a relatively small sample size and therefore, we were underpowered to detect many statistically significant associations after correction for multiple testing. Finally, our healthy controls were hospital based controls awaiting elective surgery and may not represent the general population at that time. However, our study also has strengths. We were able to leverage existing sample resources that were collected over 30 years ago and to reproduce associations with CRC from a current study. Our fecal sample was from a two day collection which may be more representative of the typical gut microbiome. We also were able to utilize other existing data sources for comparison.In this study, we were able to use whole-genome shotgun metagenomic sequencing to reproduce a number of significant findings in the same population that was assessed using 16S rRNA gene sequencing . The curS1 TableEach tab represents a specific taxonomic level or gene assignment. The mean relative abundance or average detection (presence/absence) is presented for cases and controls, and the p value from a Wald test adjusting for age, sex and body mass index (BMI) is provided.(XLS)Click here for additional data file.


Preeclampsia is the main complication of pregnancy in developing countries. Calcium starting at 14 weeks of pregnancy is indicated to prevent the disease. Recent advances in prevention of preeclampsia endorse the addition of conjugated linoleic acid. To estimate the protective effect from calcium alone, compared to calcium plus conjugated linoleic acid in nulliparous women at risk of preeclampsia. A case-control design nested in the cohort of nulliparous women attending antenatal care from 2010 to 2014. The clinical histories of 387 cases of preeclampsia were compared with 1,054 normotensive controls. The exposure was prescriptions for calcium alone, the first period, or calcium plus conjugated linoleic acid, the second period, from 12 to 16 weeks of gestational age to labor. Confounding variables were controlled, allowing only nulliparous women into the study and stratifying by age, education and ethnic group. The average age was 26.4 yrs old (range= 13-45), 85% from mixed ethnic backgrounds and with high school education. There were no differences between women who received calcium carbonate and those who did not . The group of adolescents (13 to 18 years old) in the calcium plus conjugated linoleic acid was protected for preeclampsia  independent of the confounder variables. 1. Calcium supplementation during pregnancy did not have preventive effects on preeclampsia. 2. Calcium plus Conjugated Linoleic acid provided to adolescents was observed to have preventive effect on Preeclampsia. Preeclampsia, principal cause of maternal and perinatal mortality, as well as restriction in intrauterine growth and low birth weight in developing countries, is a multifactorial disease of unknown cause for which diverse studies have been conducted with preventive purposes The population effect of calcium supplementation and linoleic acid to reduce the risk of preeclampsia was initially demonstrated in an open study, which administered 1,443 treatments to low-income pregnant women from the western part of Colombia, observing a significant reduction in preeclampsia incidence This study sought to compare the effects of administering calcium carbonate with the administration of calcium citrate plus conjugated linoleic acid for preeclampsia prevention in primigravidae patients.A case-control study was conducted nested in a cohort of primigravidae women in Cali, Colombia, in a healthcare promoter company, who received calcium carbonate (CC) or calcium plus conjugated linoleic acid (CC+CLA) combination since weeks 12-16 of the pregnancy . Pregnant patients in primiparous and normotensive state (PA <140/90 mm Hg) and adherence to prenatal control  without basic obstetric pathologies. Voluntarily accepted to enter the study before week 12 of gestation. Patients who did not comply with the inclusion criteria; when the information contained in the clinical history was insufficient and, when there was no prescription evidence or such evidence had not been claimed in the pharmacy.Development or not of preeclampsia  and exposed or not to CC or CC+CLA .The study was based on the organization's electronically systematized clinical and administrative records. The evaluation was conducted over two well-defined periods. During the first period, from 01 January 2010 to 31 December 2012, only calcium carbonate  was used. During the second period from 01 January 2013 to 31 January 2014, the pregnant women began to receive CC+CLA . Cases were defined as patients with diagnosis of preeclampsia (pregnancy-induced hypertension (≥140/90 mm Hg of blood pressure with significant proteinuria (≥300 mg/24 h). Controls were defined as patients with term pregnancy through vaginal or cesarean delivery, without pathology or with pathology different from the case, with adherence to prenatal control. For each case identified during each month, three controls were chosen through random sampling.Exposure to CC or CC+CLA was obtained from two sources. A search was made in the clinical histories of all the records corresponding to medical and nutritional prescriptions, looking for dates in which such drugs were prescribed and the corresponding week of the pregnancy. Secondly, in the drug-surveillance database, through the affiliates code, an equal search was conducted, comparing the results. For CC+CLA, the study kept records, at the start of the exposure, the date on which the pharmacy delivered the medication to the pregnant woman.® version 6.04. Centers for Disease Control and Prevention, CDC. Atlanta GA, USA, 2001). With 3 controls per case, 120 cases and 360 controls were needed. When stratification was introduced in the analysis with three groups, the prior sample size was increased threefold to reach 360 cases and 1,080 controls.During the evaluation of a preventive measure like the administration of calcium during weeks 12 to 16 of the pregnancy, it is expected that the reduction in the number of cases of the disease would be at least 50% (if the measure is effective). With these assumptions, the sample size was calculated with 95% confidence level (α= 0.05), a power (1-β) of 80%, and exposure to CC or CC+CLA in 80% of the controls, 186 cases and 186 controls were calculated . The study used the estimator of the global OR and Chi2 by Mantel & Haenszel. In the multivariate analysis, the complete model was estimated for the logistic regression, including preeclampsia as response variable and as explanatory to all the variables resulting in the bivariate analysis with statistically significant values, in addition to age independent of its statistical value. The model's performance and goodness of fit were evaluated through the analysis of residuals . The study was approved and monitored by the Organization's institutional ethics committee for research studies on humans.Univariate and bivariate analyses were performed using ChiFor the period between 2010 and 2014, a total of 4,517 records of deliveries were found of which 3,866 corresponded to primigravidae patients. Finally, 387 were selected corresponding to the case diagnosis  and, thrThe cases and controls selected showed a similar structure regarding education ; educati2= 7.69, p= 0.0055). In the other age groups no statistically significant association was found between the disease and the protective measure  and statistically significant (95% CI= 1.14-2.48). Higher education did not show protective effect .According to the 2014 report by the United Nations Development Program (UNDP-Colombia), 99% of maternal mortality occurs in developing countries, mainly affecting vulnerable populations from rural areas and low-income patients. In Colombia, the group of pregnant adolescents was the hardest hit with this condition, which gives relevance to the results of this study. The sample size  was enough to bear internal validity and allow reaching conclusions. Ethnic factors were associated to preeclampsia, as observed in previous studies 2) released in the first and the water in the latter because what is absorbed in the blood is the free ion and it acts functionally. Although only calcium is routinely used during prenatal control in many countries, given its undoubted utility as nutritional intervention, its use alone to prevent preeclampsia has had contradictory results since 2001 Over a decade ago, publications appeared demonstrating the complementarity of the results obtained through observational studies and those from randomly controlled clinical trials The cases-and-controls methodology applied by following the guidelines from the GRACE proposal Selection biases were controlled by this being a nested study of cases and controls on a cohort of pregnant patients, taking the women who began prenatal control before week 12, both in cases as in controls, guaranteeing their having the same probability of being exposed to the protective measure  and without still manifesting the disease. The detection bias of the case or non-case was minimized with the of primigravidae women who received calcium during this period. Classification bias was controlled by detecting and discarding clinical histories of poor quality.Possible confounding factors were controlled by stratifying, on the one hand, in the analysis of the patient's age variable, and on the other, by controlling the number of prior pregnancies, admitting only primigravidae participants.The following remained beyond the reach of the study: genetic factors, cigarette smoking, alcohol intake, and other events like undeclared prior abortions, which do not intervene between exposure and the result. Between the exposure and the result the only factor that mediates and which we ignore is the number of doses taken by the patient, and it is uncontrollable, but it is equally foreseeable to occur in equal manner between cases and controls.The lack of protective effect from calcium alone on preeclampsia was demonstrated preliminarily in studies conducted in North America  N= 4,589) ,589 4.A recent meta-analysis evaluated nine controlled clinical trials with supplementation of low doses of calcium  with relation to preeclampsia development, under the premise that the supplementation of high doses from the first studies  In regions with low basal intake of conjugated linoleic acid in their diet  preeclampsia incidence was high  Among the limitations of this study is that it was conducted in a population insured by the General System of Social Security with high educational level, similar to the population from developed countries and not to the general population of Colombia; more than half the patients received early calcium intervention, which is not common in the general population; however, it is a strength to assess the effect of interventions in the present study.The results obtained with CC+CLA were convincing, given the total protection found in the group younger than 18 yrs of age. The CC+CLA intervention reduces intracellular calcium, which reduces concentrations of cyclic GMP and can induce vasodilation This finding demonstrates that in the most vulnerable group, that of adolescents, supplementing with CC+CLA is protective, as found in controlled clinical trials Supplementation with CC+CLA prevented the onset of preeclampsia in adolescents, which was not observed with the supplementation of CC alone.


Genetic polymorphisms of xeroderma pigmentosum group D (XPD) in the nucleotide excision repair pathway may influence cancer susceptibility by affecting the capacity for DNA repair. Studies investigating the association between XPD Lys751Gln and Asp312Asn polymorphisms and hepatocellular carcinoma (HCC) risk reported inconsistent results. The aim of this study was to quantitatively summarize the evidence for such an association.Eligible studies were identified by searching electronic databases including PubMed, Embase, Cochrane library, and CBM, Chinese Biomedical Literature Database, for the period up to October 2014. The association of XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs).P = 0.014; Lys/Gln vs Lys/Lys: OR = 1.205, 95% CI 1.099–1.321, P = 0.000; Gln/Gln+Lys/Gln vs Lys/Lys: OR = 1.300, 95% CI 1.141–1.480, P = 0.000). In subgroup analyses by ethnicity, source of control, Hardy–Weinberg equilibrium (HWE) in controls, hepatitis B virus (HBV) infection, and statistically significant increase of HCC risk was found in East Asians, population-based studies, studies consistent with HWE, and HBV-positive subjects, but not in mixed/other populations, hospital-based studies, studies deviating from HWE, and HBV-negative subjects. With respect to XPD Asp312Asn polymorphism, no significant association with HCC risk was found in the overall and subgroup analyses.Finally, a total of 11 studies with 4322 cases and 4970 controls were included for XPD Lys751Gln polymorphism and 6 studies with 2223 cases and 2441 controls were available for XPD Asp312Asn polymorphism. With respect to XPD Lys751Gln polymorphism, statistically significant increased HCC risk was found when all studies were pooled into the meta-analysis (Gln/Gln vs Lys/Lys: OR = 1.363, 95% CI 1.065–1.744, The results suggest that the XPD Lys751Gln polymorphism contributes to increased HCC susceptibility, especially in East Asian populations. Further, large and well-designed studies are required to validate this association. The DNA repair systems play critical roles in maintaining the functions of normal cells and genomic integrity through the reversal of the damaged DNA.7 Among the DNA repair systems, the nucleotide excision repair (NER) pathway constitutes the primary mechanism for removal of bulky adducts from DNA, and thus is an important part of the cellular defense against a large variety of structural unrelated DNA lesions generated by ionizing radiation and strong alkylating agents as well as lesions formed by endogenous DNA-damaging agents like viruses.8Human cancer can be initiated by DNA damage caused by endogenous and exogenous mutagens such as ionizing radiation, UV, viruses, and environmental chemical agents.9 It codes for a DNA helicase subunit of the core transcription factor IIH, which is essential for NER and transcription and plays a critical role in transcription-coupled NER pathway.10 Single nucleotide polymorphisms (SNPs) in the exons of XPD may influence the protein activity, resulting in defects in the NER pathway and reduced DNA repair capacity. The Lys751Gln and Asp312Asn were the 2 most commonly studied SNPs in the coding region of the XPD gene.11 The XPD Lys751Gln polymorphism (rs13181) is characterized by an A to C substitution resulting in a lysine (Lys) to glutamine (Gln) amino acid exchange at position 751 in exon 23, whereas the Asp312Asn polymorphism (rs1799793) is characterized by a G to A transition causing an aspartic acid (Asp) to asparagine amino acid (Asn) exchange at position 312 in exon 10. Previous studies have demonstrated that the 2 polymorphisms were associated with lower DNA repair capacity and higher level of DNA adducts.14 Hence, it is biologically reasonable to hypothesize a potential relationship between the XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk.Xeroderma pigmentosum group D (XPD), also named excision repair cross-complimentary group 2, is 1/8 core genes  in the NER pathway of the DNA repair system. XPD maps to chromosome 19q13.3 and is composed of 23 exons.15 did not find any evidence of significant association between XPD Lys751Gln polymorphism and HCC risk in the overall populations and subgroup analysis. However, the evidence was limited because they failed to include all eligible studies in the meta-analysis.20 In addition, the source of heterogeneity was not extensively explored in this study. With respect to XPD Asp312Asn polymorphism, to the best of our knowledge, no meta-analyses on this issue have ever appeared. The exact relationship between genetic polymorphisms of XPD Lys751Gln and Asp312Asn and HCC susceptibility has not been entirely established. To provide the most comprehensive assessment of the associations between the XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk, we performed an updated meta-analysis of all available studies.Over the last 2 decades, a number of epidemiological studies have been conducted to investigate the associations between XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk, but the results remain inconsistent and underpowered. With respect to XPD Lys751Gln polymorphism, a meta-analysis by Zhang and Mou21We conducted a comprehensive literature search in PubMed, EMBASE, Cochrane library, and CBM, Chinese Biomedical Literature Database, up to October 01, 2014 using the following search strategy:  and . There was no restriction on sample size, language, population, or type of report. All eligible studies were retrieved and their references were checked for other relevant studies. In addition, we also used the “Related Articles” function in PubMed to search for other potential relevant articles. When several studies reported on the same or overlapping data, we chose the most recent or largest population. The meta-analysis was performed according to the proposal of Meta-Analysis of Observational Studies in Epidemiology group.We reviewed titles and abstracts of all citations and retrieved studies. The following inclusion criteria were used for literature selection: case–control studies that evaluated the association between XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk; used an unrelated case–control design; presented an odds ratio (OR) together with 95% confidence interval (CI) or other information for estimating OR (95% CI); and the control group did not contain malignant tumor patients. Conference abstracts, review articles, meta-analyses, case reports, editorials, and letters were excluded.Data were extracted from each study by 2 authors independently (X.L. and Q.P.) according to the selection criteria listed above. Decisions were compared and disagreements were resolved by consensus or by involving a third author (X.Q.). The following information was extracted from each study: first author, publication year, country of origin, ethnicity, genotyping method, source of control, matching variables, HCC diagnosis, total number of cases and controls, and genotype frequencies of cases and controls. When the genotype frequency or other important information was not reported, we contacted the author to get the relevant information by e-mail or telephone.Z test, and the P values <0.05 were considered significant. We evaluated the XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk using codominant, recessive, and dominant models.The strength of the association between XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk was assessed by ORs together with 95% CIs. The significance of the pooled ORs was determined by 2-based Q test was used to assess the statistical heterogeneity among studies.22 If the result of the Q test was PQ < 0.10, suggesting the existence of heterogeneity, the pooled ORs were calculated using the random-effects model (the DerSimonian and Laird method).23 Otherwise, when the result of the Q test was PQ ≥ 0.1, indicating the absence of heterogeneity, the fixed-effects model (the Mantel–Haenszel method)24 was applied. Logistic metaregression and subgroup analyses were used to identify the sources of heterogeneity among studies. The following parameters were included as covariates in metaregression analysis: ethnicity (East Asians vs mixed/other), source of controls , genotyping methods (polymerase chain reaction-restriction fragment length polymorphism vs no polymerase chain reaction-restriction fragment length polymorphism), and Hardy–Weinberg equilibrium (HWE) in controls (Yes vs No). Subgroup analyses were performed according to ethnicity, source of control, HWE status, and HBV infection. Galbraith plot analysis was performed to further explore the source of heterogeneity.The χ25 nonparametric “trim and fill” method was applied to adjust for it. The HWE was evaluated by the goodness-of-fit χ2 test for the control groups of each study . All analyses were performed using Stata software, version 12.0 . All P values were 2-sided. To ensure the reliability and the accuracy of the results, 2 authors entered the data into the statistical software programs independently with the same results.Sensitivity analysis was performed by sequential exclusion of the individual studies to assess the robustness of the results. Begg funnel plot and Egger regression asymmetry test were performed to evaluate the publication bias. If the publication bias presented, the Duval and Tweedie26 1 was a review,27 and 1 was a meta-analysis.15 Manual search of references cited in the retrieval studies identified 1 additional study.20 As a result, a total of 12 relevant studies (1 was a dissertation by a postgraduate student) met the inclusion criteria for the meta-analysis.34 The main characteristics of the studies were presented in Table 33 The genotype distributions of the controls in 2 studies were inconsistent with HWE for the XPD Lys751Gln polymorphism31 and 2 were inconsistent with HWE for the XPD Asp312Asn polymorphism.18Based on our search strategy, 34 records were found, but only 14 full-text studies were preliminarily identified for further detailed evaluation after screening the titles and abstracts. According to the exclusion criteria, 3 studies were excluded including 1 presenting insufficient data for calculating OR and 95% CI,P = 0.014; Lys/Gln vs Lys/Lys: OR = 1.205, 95% CI 1.099–1.321, P = 0.000; Gln/Gln+Lys/Gln vs Lys/Lys: OR = 1.300, 95% CI 1.141–1.480, P = 0.000). In subgroup analysis by ethnicity, statistically significant increased HCC risk was found in East Asians , but not in hospital-based studies. When stratified by HWE in controls, significantly increased HCC risk was observed in studies consistent with HWE  but not in studies inconsistent with HWE. In subgroup analysis according to HBV infection, significantly increased HCC risk was identified in HBV-positive patients  but not in HBV-negative subjects.Table P = 0.720; Asp/Asn vs Asp/Asp: OR = 1.048, 95% CI 0.920–1.195, P = 0.479; Asn/Asn+Asp/Asn vs Asp/Asp: OR = 1.031, 95% CI 0.913–1.163, P = 0.625; Asn/Asn vs Asp/Asn+Asp/Asp: OR = 0.925, 95% CI 0.660–1.295, P = 0.648). In subgroup analyses by ethnicity, source of controls, HWE in controls, and HBV infection, statistically significant association was also not detected in all subgroups (Figure Table Ph = 0.007; Gln/Gln+Lys/Gln vs Lys/Lys: Ph = 0.052; Gln/Gln vs Lys/Gln+Lys/Lys: Ph = 0.020; Table 20 was the outlier in the overall populations (Figure Ph values in the overall populations, East Asians, hospital-based studies, and studies consistent with HWE were >0.10 after excluding the study by Jiang et al.20 Interestingly, the significance of the pooled ORs for the XPD Lys751Gln polymorphism and HCC risk in the overall populations, East Asians, hospital-based studies, and studies consistent with HWE did not change after omitting this study.With respect to XPD Lys751Gln polymorphism, statistically significant between-study heterogeneity was found in the pooled analyses of total eligible studies (Gln/Gln vs Lys/Lys: s Figure . All Ph Ph value of the Q test was <0.10 in the recessive model in the overall populations (Asn/Asn vs Asp/Asn+Asp/Asp: Ph = 0.097; Table 19 was the outlier and the major source of the heterogeneity (Figure Ph values were >0.10 after excluding the study by Zeng et al19 in the overall populations, East Asians, hospital-based studies, and studies consistent with HWE. However, the significance of the pooled ORs for the XPD Asp312Asn polymorphism and HCC risk in the overall populations, East Asians, hospital-based studies, and studies consistent with HWE were also not changed by excluding this study.With respect to XPD Asp312Asn polymorphism, the y Figure . The Ph 17 and Long et al31 in which the control populations were significantly deviated from HWE. The significance of all ORs was not altered after excluding the 2 studies. For the XPD Asp312Asn polymorphism, sensitivity analysis was also performed by excluding those 2 studies by Wu et al16 and Guo et al18 in which the control populations were inconsistent with HWE, and the significance of all ORs was also not altered.Sensitivity analysis was performed by sequential omission of individual studies for both the XPD Lys751Gln and Asp312Asn polymorphisms. For analyses of pooling >3 studies, the significance of ORs was not materially influenced by omitting any single study. For the XPD Lys751Gln polymorphism, sensitivity analysis was further performed by excluding the studies by Yao et alP values of the Egger tests for both the XPD Lys751Gln and Asp312Asn polymorphisms were all >0.05, providing statistical evidence of the funnel plots’ symmetry. The results suggested that publication bias did not exist in this study.Begg funnel plot and Egger test were used to access the publication bias of literatures. The shape of funnel plots did not reveal any evidence of obvious asymmetry Figure , and the36 XPD is one of the most important proteins in NER and closely associated with NER pathway coordination by interacting with most components of the NER short-patch pathway. Genetic polymorphisms and mutations in XPD may influence the protein activity, resulting in defects in the NER pathway and reduced DNA repair capacity37; thus, modulating cancer susceptibility including HCC. To date, emerging epidemiological studies have evaluated the association of XPD Lys751Gln and Asp312Asn polymorphisms with HCC risk, but the results remain controversial and underpowered. Therefore, we performed this meta-analysis including all available studies to provide the most comprehensive assessment of the associations. The results based on 12 studies suggested that the XPD Lys751Gln polymorphism was significantly associated with increased HCC risk. However, our data did not support a genetic association of the XPD Asp312Asn polymorphism with HCC susceptibility.NER pathway of the DNA repair systems is the primary mechanism for the removal of bulky adducts from DNA, and thus is an important part of the cellular defense against a large variety of structural unrelated DNA lesions.38 Therefore, it is biologically plausible that the XPD Lys751Gln polymorphism plays a critical role in hepatocarcinogenesis. This hypothesis was confirmed by our meta-analysis.XPD is an important DNA repair gene in the NER pathway. XPD Lys751Gln polymorphism is located at position 751 in exon 23 of the XPD gene with an A to C substitution leading to a Lys to Gln amino acid exchange. Inherited functional polymorphisms in exons of the XPD gene may influence the protein function, resulting in differences of the individual NER and DNA repair capacity that may affect the susceptibility to cancers. It has been reported that the Gln allele of the Lys751Gln polymorphism within the XPD gene was associated with higher DNA adduct levels and lower DNA repair efficiency.15 which was shown as an outlier in Galbraith plot analysis, statistically significant increased HCC risk was still found in the overall populations and East Asians but not in the mixed/other populations. The inconsistent results among diverse ethnicities demonstrated different effects of the XPD Lys751Gln polymorphism on HCC risk in different ethnic genetic backgrounds. Nevertheless, because of the small number of eligible studies among mixed/other populations, the observed association between the XPD Lys751Gln polymorphism and HCC risk in mixed/other populations is likely to be caused by chance because a study with small sample sizes may have insufficient statistical power to detect a slight effect or may have generated a fluctuated estimation. In this study, there was only 1 study for mixed/other populations concerning the XPD Lys751Gln polymorphism on HCC risk.39 Therefore, the results from the mixed/other populations should be interpreted with caution.In the present study, we observed that the XPD Lys751Gln polymorphism presented a risk factor for HCC in East Asians, but not in mixed/other populations. When we excluded the study by Zhang and Mou,40 Selecting of proper and representative population-based controls is important in eliminating biases in such genetic association studies. Therefore, we performed subgroup analysis stratified by source of controls. The results revealed that the XPD Lys751Gln polymorphism was associated with an increased HCC risk in population-based studies, but not in hospital-based studies. Therefore, a methodologically preferable design, such as using a proper and representative population-based high quality study, is of great importance in case–control studies.It was reported that hospital-based studies have inherent selection bias because of the fact that the controls just represent a sample of ill-defined reference population and may not be representative of the study population or the general population, particularly when the genotypes under investigation were associated with the disease-related conditions that the hospital-based controls may have.41 Because of reasons of disequilibrium, the results of genetic association studies might be unreliable when the distributions of genotypes in the control groups deviate from HWE. In the present study, the genotype distributions of the controls in 2 studies were inconsistent with HWE for the XPD Lys751Gln polymorphism.31 Therefore, we performed subgroup analysis according to HWE in controls. When excluding the studies that were inconsistent with HWE, the results were persistent and robust, suggesting that this factor probably had little effect on the overall estimates.Evidence has demonstrated that studies disobeyed the law of HWE may be as a result of genetic reasons including nonrandom mating, or the alleles reflect recent mutations that have not reached equilibrium, as well as methodological reasons including biased selection of subjects from the population or genotyping errors.31 and Xu et al.32 The possible mechanism for the preferentially increased HCC risk of XPD Lys751Gln polymorphism in HBV-positive patients is that the DNA repair functions of the XPD have been reduced by the XPD Lys751Gln polymorphism, making them more vulnerable to cancer development. However, the hypotheses need to be proved in future studies.Hepatocarcinogenesis has been found to be closely correlated with chronic HBV or HCV infection, and in fact, a certain proportion of chronically infected HBV and HCV individuals will develop HCC. HBV belongs to a family of DNA viruses called hepadnaviruses. The oncogenic potential of HBV has been attributed to its ability to integrate into host cellular DNA, which impairs the genomic integrity and activates neighboring cellular genes directly to offer a selective growth advantage to liver cells. In addition, the production of hepatitis B x protein can serve as a transactivator on various cellular genes for cell growth and tumorigenesis. Therefore, there might be differences in carcinogenetic mechanisms of HCC between the HBV-positive patients and HBV-negative subjects. In the present study, we found that the XPD Lys751Gln polymorphism was significantly associated with increased HCC risk in HBV-positive patients but not in HBV-negative subgroup, which was consistent with the studies conducted by Long et al42 In this study, statistically significant between-study heterogeneity was observed in the pooled analyses of total eligible studies. To identify the sources of heterogeneity, we performed subgroup analyses and metaregression. Subgroup analyses indicated that the heterogeneity was still evident in most of the subgroups for both the XPD Lys751Gln and Asp312Asn polymorphisms. Metaregression analysis revealed that none of the investigated variables was the source of heterogeneity for the 2 SNPs. Subsequently, we performed Galbraith plots to further investigate the heterogeneity. For the XPD Lys751Gln polymorphism, Galbraith plots spotted 1 study20 as the outlier and the possible source of heterogeneity. For the XPD Asp312Asn polymorphism, Galbraith plots also spotted 1 study19 as the outlier and the possible source of heterogeneity. When excluding the study by Jiang et al20 for the XPD Lys751Gln polymorphism and the study by Zeng et al19 for the XPD Asp312Asn polymorphism, all Ph values in the overall populations and subgroup analyses were >0.10. Interestingly, the summary ORs for the XPD Lys751Gln and Asp312Asn polymorphisms in different comparison models in the overall population and subgroup analyses were not materially changed by excluding the outlier studies, suggesting that our results were robust and reliable.The major concern in a sound meta-analysis is the degree of heterogeneity that exists between studies because heterogeneous data are prone to produce misleading results, and finding the sources of heterogeneity is one of the most important goals in a meta-analysis.Despite our efforts to perform a comprehensive analysis, limitations in this study should be acknowledged. First, in subgroup analysis by ethnicity, the included studies regarded only East Asians and mixed/other populations. Data concerning other ethnicities such as whites and Africans were not found. Therefore, additional studies are needed to evaluate the effect of this functional polymorphism on HCC risk in different ethnicities. Second, the controls in the eligible studies were not uniformly defined. Although the controls were mainly selected from healthy populations, some had benign diseases such as liver cirrhosis, HBsAg positivity, and so on. Therefore, nondifferential misclassification bias was possible because these studies may have included the control populations who have different risks of developing HCC. Third, our results were based on unadjusted estimates. We did not perform analysis adjusted for other covariates such as sex, age, drinking and smoking status, HBV and HCV carrier status, environmental factors, and so on because of the unavailable original data in the eligible studies.Despite the limitations, the results suggest that the XPD Lys751Gln polymorphism contributes to increased HCC susceptibility, especially in East Asians. Further, large and well-designed studies are required to validate this association.


XPD) gene with the risk of non-Hodgkin’s lymphoma (NHL), but the conclusions have been inconsistent. Therefore, we performed this meta-analysis to more precisely estimate these relationships. A systematic literature search was performed using the PubMed, Embase, and Chinese Biomedical (CBM) databases. Ultimately, 6 studies of Asp312Asn, comprising 3,095 cases and 3,306 controls, and 7 studies of Lys751Gln, consisting of 3,249 cases and 3,676 controls, were included. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of each association. Overall, no association was observed between the Asp312Asn polymorphism and NHL risk  or between the Lys751Gln polymorphism and NHL risk . Furthermore, subgroup analyses did not reveal any association between these polymorphisms and ethnicity, the source of the controls, or the NHL subtype. These results indicated that neither the Asp312Asn nor Lys751Gln XPD polymorphism was related to NHL risk. Large and well-designed prospective studies are required to confirm this finding.Polymorphisms in DNA repair genes may alter DNA repair capacity and, consequently, lead to genetic instability and carcinogenesis. Several studies have investigated the association of the Asp312Asn and Lys751Gln polymorphisms in the xeroderma pigmentosum complementation group D ( Non-Hodgkin’s lymphoma (NHL) represents a large heterogeneous group of B-cell and T-cell lymphomas characterized by uncontrolled malignant clonal expansion. Approximately 80%-90% of all NHLs originate from B cells, i.e., B-cell lymphomas, which are further categorized into two major subtypes: diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) . The incGenomic DNA damage caused by exposure to either endogenous or exogenous toxic substances, if not repaired, may lead to tumorigenesis. DNA repair pathways continuously correct damaged DNA to maintain genomic stability and homeostasis . DefectsXPD, also known as excision repair cross-complementation group 2 (ERCC2), is located at chromosome 19q13.3. It is one of the seven genetic complementation groups that encode for components of the NER pathway, which restores DNA damage caused by ionizing radiation and chemotherapy , and dominant [(GA + AA) vs. GG] models, as well as via allele comparison (A vs. G). Similarly, the pooled ORs for Lys751Gln were calculated under the homozygous (CC vs. AA), heterozygous (AC vs. AA), recessive [CC vs. (AC + AA)], and dominant [(AC + CC) vs. AA] models, as well as via allele comparison (C vs. A). Subgroup analyses were further performed according to ethnicity, source of the controls, and NHL subtype.Q-test was used to assess between-study heterogeneity. If there was no heterogeneity (P > 0.10), the fixed-effect model (the Mantel–Haenszel method) was used [The Chi square-based was used . Otherwiwas used . The logwas used  SensitivP values were two-sided, and P values less than 0.05 were considered significant.The analyses were performed using STATA software . All A total of 11 potentially relevant publications were identified from the PubMed, Embase, and CBM databases. After assessment of the abstracts and the full texts, 2 publications ,24 were Overall, 3,095 NHL cases and 3,306 controls for Asp312Asn and 3,249 NHL cases and 3,676 controls for Lys751Gln were included in the final meta-analysis. Three studies were conducted on Caucasians, 1 on Asians, and 2 on mixed ethnicities for the Asp312Asn polymorphism; 3 were conducted on Caucasians, 2 on Asians, and 2 on mixed ethnicities for the Lys751Gln polymorphism. With respect to the source of the controls, for Asp312Asn, 5 studies were population-based and 1 was hospital-based; for Lys751Gln, 5 studies were population-based and 2 were hospital-based. With respect to the NHL subtype, for Asp312Asn, 4 studies examined DLBCL and 5 examined FL, whereas for Lys751Gln, 5 studies examined DLBCL and 6 examined FL.As shown in Table Upon stratifying the data by ethnicity, source of the controls, and NHL subtype, no association between the Asp312Asn polymorphism and NHL risk was detected.Similar to the Asp312Asn polymorphism, the Lys751Gln polymorphism did not display any significant association with NHL risk   or Lys751Gln polymorphism of the XPD gene . Therefore, the fixed-effect model was chosen for the analyses using all genetics models.No heterogeneity was observed among all studies for the Asp312Asn polymorphism  and Lys751Gln polymorphisms  of the XPD gene were symmetrical, indicating that there was no evidence of publication bias among the studies included in the meta-analysis.The shapes of the funnel plots for the Asp312Asn (homozygous: XPD gene with NHL risk have been investigated by different research groups, but the conclusions were contradictory. The most possible reason for the discrepancies between studies is the small sample size of each study, which limits the statistical power to detect the potential effects of polymorphisms. We performed the present meta-analysis via a systematic literature search to combine the results of all available studies, which may be useful for evaluating the genetic factors that contribute to NHL. In this meta-analysis, which included 3,095 cases and 3,306 controls for Asp312Asn and 3,249 cases and 3,676 controls for Lys751Gln, we found that neither the Asp312Asn nor the Lys751Gln polymorphism was significantly associated with NHL risk. The subgroup analysis also failed to reveal any association between the examined polymorphisms and NHL risk according to ethnicity, source of the controls, or NHL subtype.The associations of the Asp312Asn and Lys751Gln polymorphisms of the XPC gene, have been shown to associate with overall cancer risk [XPD gene may weaken the interaction between the TFIIH complex and XPD, abolishing the stimulation of the helicase activity of XPD, thereby reducing DNA repair and transcription capacity and producing abnormal responses to apoptotic signals [The tumorigenesis of NHL is a complex multi-step process that leads to clonal, uncontrolled, malignant lymphocyte proliferation. Well-established pathogenic factors of NHL include environmental and microbial factors, as well as immune disorder, which may result in malignant transformation. For instance, exposure to environmental carcinogens can result in various types of DNA damage that subsequently induce the development of NHL . In addicer risk . XPD, a cer risk . The XPDcer risk . These a signals .XPD gene polymorphisms have been shown to associate with the risk of a wide range of cancers, including gastric cancer [c cancer , breast c cancer , bladderc cancer , and so c cancer . In thisThere are several limitations in our meta-analysis that remain to be addressed. To date, there are only 6 studies for Asp312Asn and 7 for Lys751Gln that have investigated the association between these polymorphisms and NHL risk. Moreover, the sample sizes of most of these studies are relatively small. As a result, this meta-analysis may have limited statistical power to detect a potential association. In addition, different genotyping methods with differing accuracy were used in previous investigations, which might lead to a bias to some extent. Additionally, because other detailed data, such as age, sex, smoking habits, and alcohol consumption, were not available, our conclusions were solely based on unadjusted estimated ORs.XPD gene with NHL risk. Large, well-designed, prospective studies are required to verify our findings.In conclusion, this meta-analysis suggests that there is no significant association of either the Asp312Asn or the Lys751Gln polymorphism of the


To evaluate the effects of the interactions between polymorphisms in Nalp3, caspase-1, and interleukin(IL)-1β genes and occupational dust exposure on the risk of silicosis.p-values using logistic regression models adjusted for selected confounders.We conducted a population-based case-control study in a large iron mine in China. Between January 2006 and December 2009, we identified 179 patients with silicosis to evaluate as cases and 201 individuals without silicosis to evaluate as controls. We estimated cumulative dust exposure (CDE) for all subjects and we genotyped polymorphisms in Nalp3, caspase-1, and IL-1β genes. We estimated odds ratios(ORs), 95% confidence intervals(95%CIs), and 3×year and among smokers, those with the GA genotype of Ex2+37G>A in caspase-1 had a higher risk of silicosis than those with other genotypes .After adjusting for age, smoking status, and CDE, subjects with the CT genotype of Ex4-849C>T in Nalp3 and the GA genotype of Ex2+37G>A in caspase-1 had increased risks of silicosis . Among subjects younger than 70 years old, those with the CC genotype of IVS8-7652A>C in Nalp3 had a lower risk of silicosis than those with other genotypes (adjusted OR[95%CI] = 0.24[0.06–0.88]). Among subjects aged 70 years and older, those with the CT genotype of Ex4-849C>T in Nalp3 and those with the GA genotype of Ex2+37G>A in caspase-1 had a higher risk of silicosis than those with other genotypes . Among subjects with CDE greater than 120 mg/mGenetic polymorphisms in Nalp3 and caspase-1 may be associated with individual susceptibility to silicosis, especially when the polymorphisms interact with age, CDE, or smoking status. Silicosis is an occupational fibrotic lung disease that is induced by the inhalation and deposition of free crystalline silica dust. CrystalCurrent evidence from clinical studies and experimental animal models suggests that chronic pulmonary inflammation is an essential process in the pathogenesis of silicosis,13. ReceThe Nalp3 inflammasome is an intracellular, multiprotein complex composed of Nalp3, at least one adaptor protein, and caspase-1, which is an IL-1β-cleaving enzyme. Once acIn order to investigate the interactions of genetic polymorphisms of Nalp3, caspase-1, and IL-1β with occupational dust exposure and the joint effects on the risk of silicosis, we conducted a case-control study of a large cohort of workers in a large iron mine. Individual dust exposure was estimated by work history and a dust exposure matrix. We examined the variant frequencies and genotype distributions of the 5 SNPs for each of the subjects and compared these distributions to the presence of silicosis.Between January 2006 and December 2009, we identified 179 patients with silicosis and 201 individuals without silicosis from an iron mine that belongs to Wuhan Iron and Steel Corporation located in Huangshi City, Hubei Province, China. All workers that were exposed to silica received chest radiographs every 2 to 4 years. These test results and medical records, including date and stage of silicosis diagnosis and progression, were maintained by the mine hospital. The cases of silicosis were diagnosed by at least 3 qualified physicians according to China National Criteria for silicosis, which is consistent with International Labor Organization Classification. We freq3×year) for each subject. Detailed dust exposure estimations have been described in previous reports = 26.37 [3.35–207.39]), were older than 70 years old (OR [95%CI] = 5.19 [1.88–14.35]), or were smokers (OR [95%CI] = 3.47 [1.40–8.64]).The results of our stratification analysis for the SNPs of caspase-1 are presented in 3×years.In this case-control study, 5 SNPs in Nalp3, IL-1β, and caspase-1 genes were evaluated to define the risk of silicosis in a Chinese population. We found 2 SNPs  that were significantly associated with an increased risk of silicosis. The risk of silicosis was greater when CDE was greater than 120 mg/mSilica is one of the most ubiquitous minerals on the earth and occupational silica exposure is very common. Inhalation of silica through occupational exposures may result in silicosis, which is one of the most important occupational diseases worldwide. In EuroPrevious studies have shown that the incidence of silicosis may be influenced by genetic factors such as IL-4, IL-1, and tumor necrosis factor (TNF)-α,10,24. WThe Nalp3 inflammasome is essential for the inflammatory response and subsequent development of pulmonary fibrosis after the inhalation of silica. Polymorphisms in Nalp3 that lead to amino acid changes have been described in Crohn’s disease, cardiovascular disease, and human immunodeficiency virus-1 infection,29,30. WCaspase-1, the first identified caspase, is involved in the processing and secretion of pro-inflammatory molecules. RecentlIL-1β is known to be a very strong pro-inflammatory cytokine and it has been implicated in inflammatory disorders. Some stIn conclusion, we found 2 SNPs  that are associated with an increased risk of silicosis in a Chinese population. Further validation studies with larger, diverse populations are warranted to confirm our findings.


Background. Functional dyspepsia (FD) is a functional upper gastrointestinal disorder with significant morbidity and medical costs. Previous studies investigated the association of G-protein β3 (GNB3) genetic polymorphisms with FD but with inconsistent results. Therefore, we performed a meta-analysis to derive a precise estimation of the relationship between GNB3 polymorphisms and FD. Methods. We searched different databases including PubMed, EMBASE, CNKI, and the Ovid Library to gather eligible studies on GNB3 polymorphisms and FD. The association was assessed by the odds ratio (OR) with 95% confidence intervals (CI). Results. We identified 12 studies with 1109 cases and 2853 controls for the analysis. We found no associations of GNB3 C825T polymorphism with FD in the overall population . Subgroup analyses by genotyping method indicated that the magnitude of association was strengthened for additive model . Sensitivity analysis did not reveal significant associations under all models. Conclusions. This meta-analysis demonstrates that GNB3 C825T polymorphism may not be a risk factor for FD. Functional dyspepsia is one of the most common chronic gastrointestinal disorders encountered in clinical practice , with pr Helicobacter pylori (H. pylori) infection, and serum ghrelin level, are repeatedly announced to be implicated in the pathogenesis of FD [However, the pathogenesis contributing to the huge amount of intermittent functional dyspepsia currently remains unclear. FD is a multifactorial disease which is likely to be the consequence of genetic factors, environmental stimuli, and their interaction. Several possible etiological factors, including abnormal gastrointestinal motility, visceral hypersensitivity, delayed gastric emptying, dysfunction of the autonomic nervous system,is of FD –14. In ais of FD –17. Neveis of FD , 19.α, β, and γ subunits, which act as switches for signal transduction from extracellular space into the cell and are expressed in all cells of the human body [α-GTP and Gβγ complexes, resulting in a variety of complex physiological responses such as cell proliferation, chemotaxis, and vasoconstriction [β3 (GNB3) subunit plays a vital role on several signal transduction receptors and effectors, encoded by the GNB3 gene located on chromosome 12p13 which comprises 11 exons and 10 introns [G-proteins are heterotrimers composed of man body . Concrettriction . G-prote introns , 22. Rep introns .To date, association between GNB3 C825T polymorphism and FD has been extensively pursued with contradictory results in several epidemiological studies –27. GeneTo search for all the studies investigating the association of the GNB3 polymorphism with FD risk, we conducted a systematic computerized literature search from PubMed, EMBASE, the Ovid Library, and the Chinese National Knowledge Infrastructure (CNKI) prior to March 2015 using the following keywords and subject terms: “functional dyspepsia” or “FD,” “G-protein beta3” or “GNB3,” “mutation,” “variant,” and “polymorphism.” The full text of the retrieved articles was scrutinized to inspect whether information on the topic of interest was included. To ensure a comprehensive acquisition of literature, independent supplemental manual searches were established on the reference lists of the retrieved articles, finding additional studies that were not identified initially. To avoid the local literature bias, the search was diffusely designed without language and region restrictions. The literature retrieval was performed independently by two investigators and discrepancies were resolved by reaching a consensus or input from a third investigator if required.As a prerequisite, the selection of studies in our meta-analysis was abided by the predefined inclusion and exclusion criteria: (1) population-based or hospital-based case-control or cohort studies evaluating the relationship between the GNB3 C825T polymorphism and functional dyspepsia; (2) sufficient data on genotypic and allelic frequencies between FD patients and controls for estimating an odds ratio (OR) with a 95% confidence interval (CI); and (3) studies with related clinical characteristics limited to those using human subjects and containing demographic information of subjects. To avoid selection bias, articles regarding controls in which the genotype distribution deviated from the Hardy-Weinberg equilibrium (HWE) and cases simultaneously compounded with another disease, such as irritable bowel syndrome (IBS), were also included. Two reviewers then assessed the full text of the retrieved studies independently for their suitability of inclusion. Any discrepancies concerning articles meriting inclusion between reviewers were resolved by a consensus meeting of three authors.χ2 test. Any encountered discrepancies were adjudicated by a discussion until a consensus was reached.To make sure of the accuracy of the data, the data were independently gathered in duplicate by two investigators on the basis of a standard protocol. From each qualified study the following data were abstracted: the first author, the year of publication, FD diagnostic criteria, genotyping method, baseline characteristics of the study population , total numbers of cases and controls and the genotype distribution, and the Hardy-Weinberg equilibrium (HWE) using the http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp). Scores were based on the selection, comparability, and exposure (case-control studies) or outcome (cohort studies) of the studies. To avoid selection bias, studies of poor quality were not rejected in this meta-analysis.The quality of each selected study was assessed independently by the same two investigators according to the Newcastle-Ottawa Scale (NOS) (χ2 test (P > 0.05) [Q test. In addition to a visual assessment using the forest plots, we calculated the inconsistency index (I2) to quantify the extent of between-study variability, which represented the proportion of heterogeneity not explained by random variation [I2 > 50%  [Q test was significant (P < 0.05) or I2 > 50%, indicating the presence of heterogeneity, a random-effects model (the DerSimonian and Laird method) was used [P < 0.05 for Egger's test indicating significant publication bias [P value < 0.05 was defined as statistical significance. All statistical analyses were conducted using Stata 12.0  and Review Manager 5.0 .Before estimating the relationship between the GNB3 C825T polymorphism and FD risk, a test that detects whether the genotype frequencies of the controls were in HWE was applied to evaluate the data quality, using a  > 0.05) . Odds raariation . Statistgeneity) . When thwas used ; otherwiwas used . To explion bias . All tesIn total, our initial literature search yielded 85 published studies, of which 63 studies were excluded for not investigating the association of GNB3 C825T polymorphism with FD after screening titles and abstracts. After the subsequent reviewing of the remaining 22 articles, 5 were excluded for not being case-control or cohort articles. Seventeen potentially relevant studies were retrieved for full-text evaluation, of which 5 further studies were excluded with insufficient data. Finally, 12 case-control studies with a total of 1109 cases and 2853 controls were included in the present meta-analysis. The study selection is summarized in The detailed characteristics of all included studies are shown in P = 0.26). No evidence of significance was identified in additive  model, as well as in dominant  model. In one out of the four contrast models considered (recessive model), there was a substantial degree of heterogeneity as indicated by the large value of the I2 index (I2 = 59%). Thus, the pooled OR was estimated by utilizing the random-effects model under this model. Likewise, in the recessive model (CT + TT versus CC), comparison of CT + TT with CC genotype failed to generate a significant association with FD risk .Four different genetic models  were assumed to observe the association between GNB3 C825T polymorphism and FD risk. The main results of the overall analysis are presented in P > 0.05 for all). In the view of region, the subjects who came from Asia were analyzed from the data of 8 studies, failing to yield any significant association between GNB3 C825T polymorphism and FD risk . Likewise, no association was found among the participants from America. The studies were also divided into subgroups based on the genotyping method of the C825T polymorphism. Only two studies were performed in the application of each following genotyping method: direct sequencing, molecular beacon assay, and TaqMan assay, respectively [P > 0.05 for all). As shown in P = 0.02).Considering the fact that the definition of FD, region, and the genotyping method might bias the overall results , subgrouectively , 34–36. ectively , 38, 39.To further strengthen the confidence of current meta-analysis, sensitivity analyses were conducted while restricting the studies on some predefined variables that might hold the potential contribution to the pooled OR of overall results. We excluded studies by Holtmann et al. , Li et aP = 0.015). Additionally, as reflected by Egger's test . However, two moderate  and an obvious (P = 0.021) publication bias were detected under the additive model among sensitivity analysis based on HWE, overlap disease of IBS, and the NOS Score, respectively.Lastly, funnel plots were constructed and Egger's test was employed to assess publication bias of this study. Regarding the overall analysis, only the additive model displayed an asymmetric funnel plot, while Egger's test confirmed the presence of greater publication bias  infection, and serum ghrelin level contribute to the occurrence of FD, and some psychological disturbances together with lifestyle factors may also play a critical role in the etiology of FD.Functional dyspepsia is a significant chronic disease that leads to reduced quality of life among patients both physically and psychologically. Genetic factors as well as gastrointestinal dysfunction, dysfunction of the autonomic nervous system,β3 subunit, which was demonstrated to result in a truncated deletion but functionally active splicing variant of 41 amino acids [G-protein regulates the functions of ion channels and protein kinases, comprising a family of ubiquitously distributed signal transduction proteins. Most membrane receptors rely on heterotrimeric G-proteins to activate or inhibit intracellular signaling cascades. Hence, a polymorphism of a G-protein may lead to a wide number of pathophysiological effects, as many hormones, neurotransmitters, and sensory stimuli exert their effects on cells by binding to G-protein coupled receptors. Reportedly, a novel polymorphism of C825T has been detected in exon 10 of GNB3 gene encoding the no acids . Cholecyno acids . Thus, ino acids , 44. Furno acids  and thiano acids , whereasno acids . In thisI2 = 59%).Evidence of the correlation between GNB3 C825T polymorphism and FD has been accumulating steadily over the past decade with inconsistent results. Holtmann et al.  show thaP = 0.02). However, it could not be ignored that the deficiency of studies is embodied in the subgroup analysis limited on genotyping method under the additive model. Besides, 4 out of 5 studies included in the subgroup analysis above are hailed from Asia. Thus, in view of the relatively small sample sizes of this subgroup analysis, the positive analytic results should be interpreted preliminarily and cautiously.Region or ethnicity is generally one of the causes of discrepancies existing in the overall analyses. When it comes to GNB3 C825T polymorphism, the T allele frequency is reported to be higher in Asian populations (42%–53%) than Caucasian populations (27–42%) , 48. HenThe negative association of all overall analyses discovered here, combined with the nearly analogous outcome of each subgroup analysis, is an obvious indication of the need to perform additional sensitivity analyses, for the sake of enhancing the reliability of present meta-analysis. Statistically significant violations of HWE or magnitude of deviations from HWE may contribute to the problem of replicating postulated gene-disease associations across different studies. Additionally, Trikalinos et al. suggested that gene-disease association meta-analysis should routinely scrutinize the potential impact of HWE violations as well as deviations from the exact frequencies expected under HWE . AccordiP = 0.018), which was completely opposite to our study. As mentioned above and previous studies, the GNB3 825T allele is associated with enhanced G-protein activation and thereby altered signal transduction response, resulting in motor or sensory abnormalities of the gastrointestinal tract. Therefore, it is more reasonable and precise to regard the 825T allele as the susceptible risk gene for FD. But conversely, the 825C allele was employed as the experimental group to evaluate the association between GNB3 C825T polymorphism and the risk of FD in the study by Dai et al., which was unreasonable and may lead to a contrasting observation of the significant OR for the CC genotype. Besides, the sample size  is too limited to reach conclusive findings regarding this antecedent meta-analysis. Nonetheless, the results of the present meta-analysis should be interpreted within the context of several potential limitations. First of all, although we have made every effort to find suitable studies, we cannot be sure if some appropriate studies were overlooked and there may be other eligible studies that were not published and indexed by electronic databases. Furthermore, meta-analysis can be prone to produce publication bias; despite the literature research of focusing on papers published without language and country restrictions, a palpable publication bias was detected with Egger's test among overall analysis under the additive genetic model (P = 0.015). Second, although more participants are employed compared to Dai's study, our analysis is still limited by the relatively small number of included studies. The rarity of included studies would further reduce the importance of the quantitative combination of ORs, while preventing us from constructing more extensive subgroup analysis or sensitivity analysis. Third, the diagnostic criteria for FD are not uniform, with earlier publications adopting Rome II criteria and later ones adopting Rome III criteria (The strength of our study is based on its compliance with criteria for rigorously performing a meta-analysis. Of note, meta-analysis has been regarded as a powerful tool for pooling data from several studies, overcoming the problem of small sample numbers as well as insufficient statistical power of genetic association studies of complex diseases . A previcriteria , inevitaIn conclusion, the available evidence of our meta-analysis shows that there are no associations between GNB3 C825T polymorphism and FD risk. Considering the limitations mentioned above, well-designed studies with larger sample sizes are highly desired to validate our findings and elucidate the potential mechanism linking GNB3 to FD.


We conducted this meta-analysis to address the open question of a possible association between maternal socioeconomic status and congenital heart defects (CHDs).We searched MEDLINE and EMBASE from their inception to January 1, 2014 for case-control and cohort studies that assessed the association between maternal socioeconomic status and the risk of CHDs. Study-specific relative risk estimates were polled according to random-effect or fixed-effect models.From 3343 references, a total of 31 case-control studies and 2 cohort studies were enrolled in this meta-analysis, including more than 50,000 cases. We observed that maternal educational attainment, family income and maternal occupation were negatively associated with an 11% , 5%  and 51%  increased risk of CHDs, respectively. In a subgroup analysis by geographic region, the results were inconsistent for the European region  and USA/Canada region  in maternal educational attainment.In summary, this meta-analysis suggests that a lower degree of maternal socioeconomic status is modestly associated with an increased risk of CHDs. However, further investigations are needed to confirm the association. Congenital heart defects (CHDs) are the most common group of congenital malformations, affecting almost 1% of live births throughout the world Various approaches to the conceptualization and measurement of socioeconomic status (SES) have been taken, reflecting both different theoretical orientations and the exigencies of conducting studies. In our study, we used the most common measures, indexes, and ecological measures of SES, which is typically characterized by educational attainment, family income level and occupational prestige. According to the International Standard Classification of Occupations (ISCO-08) An increasing number of studies to date have focused on the association between maternal SES and CHDs; however, the results have been ambiguous, perhaps because of inadequate sample sizes. Therefore, we conducted a meta-analysis to quantitatively assess the effect of maternal SES on CHDs.A computerized literature search was conducted by two independent investigators (Yu and Feng) in MEDLINE and EMBASE from their inception to January 1, 2014. We searched relevant studies using the following strategy:  AND  AND . In addition, we conducted a search with a broader range on environmental teratogens and CHDs and checked the references in relevant retrieved and review articles. In this way, we identified information about other related studies.We selected articles that (1) were original epidemiologic studies , (2) examined the association between maternal SES and CHDs overall or any one of the CHD subtypes in infants, (3) were published in the English language, (4) reported RRs  and associated 95% confidence intervals (CIs) or had raw data available, and (5) defined CHDs or one of the CHD subtypes as an outcome. Articles that reported results from more than one population were considered separate studies. Non-peer-reviewed articles, experimental animal studies, ecological assessments, correlational studies and mechanistic studies were excluded.Data extraction was conducted separately by two reviewers (Yu and Feng) working independently. If differences of opinion arose, these were resolved by discussion between the two. The studies meeting the inclusion criteria were reviewed to retrieve information of interest including study characteristics ) and to record reported effect estimates and the associated 95% confidence interval (CI). If effect estimates were not available, raw data were extracted. For original studies that reported risk estimates in association with SES according to more than one measure, each estimate was extracted and its own association with the specific SES then analyzed. The information on the country where the study was conducted was then classified according to the geographical area  and the country's income level (high-income and middle or low income). The education attainment and family income were evaluated by the lowest vs. the highest reported in the enrolled studies. Information on occupational social class was collected in the evaluated studies and coded according to the International Standard Classification of Occupations (ISCO-08) (unskilled (I), skilled (II), intermediate (III) and professional (IV)).RR was used as the measure for the summary statistics of associations of maternal SES with CHD risk. To simplify the procedure, RR was used to represent all reported study-specific results from cohort studies and OR from case-control studies. RR estimates and 95% CIs were extracted from each study for CHDs overall and CHD subtypes. To augment the comparability of different SES categories in the studies, the lowest and highest SES categories were compared. We back-calculated the point estimate and 95% CI if the original study did not report the risk estimates in this order. If the original study did not report estimates in the form of RR or OR, we used standard equations to recalculate the risk estimates and 95% CI from the raw data presented in the study.The strength of the association of maternal SES with CHD risk was evaluated by RR with a 95% CI. We calculated pooled RR and accompanying 95% CI for the lowest vs. the highest categories of both income and education. Occupation included 4 groups, from low to high level, and pooled RRs with 95% CIs were calculated for the first vs. the fourth level, the second vs. the fourth, and the third vs. the fourth.Q and 2I statistics were used to test for heterogeneity across studies P<0.05 or 2I≧50%), the random-effects model was used. This model provided a more appropriate summary effect estimate among heterogeneous study-specific estimates. If the study showed no evidence of heterogeneity, a fixed-effects analysis was used, applying inverse variance weighting to calculate summary RR estimates Cochran P value of <0.05 for the two above-mentioned tests. All statistical analyses were performed with STATA .Publication bias was assessed by visual inspection of a funnel plot with asymmetry, using both Egger's linear regression The search strategy generated 3343 citations, among which 33 were identified in the final analysis for 53,358 incident cases . All of The overall results of this meta-analysis provided evidence for a significant increase in the risk of CHDs among the lowest socioeconomic categories for all 3 socioeconomic indicators –4. HeterP<0.001, 2I = 61.3%), with no publication bias  (2I = 0.0%) or publication bias (Egger's test: P = 0.475) . We found that decreasing maternal educational attainment was associated with an 11% increase in the risk of CHDs  . Statist = 0.14) . After s= 0.475) . For the. Many factors could explain this finding. First, poor education is always accompanied by smoking The purpose of the current study was to investigate the association between SES and CHDs. SES is customarily determined by educational achievement, family income and occupational prestige. To examine this association, we conducted a meta-analysis including 29, 6 and 5 studies of maternal education, family income and maternal occupation, respectively. Our findings indicated an increased incidence of CHDs among the lowest SES classifications in maternal education (11%), family income (5%) and maternal occupation (51%) compared with the highest classification of the corresponding SES. Moreover, for education stratified by the country's income group, a 10% increment was found among high-income countries. Furthermore, a significant increment (44%) was found among middle- or low-income countries. The results were inconsistent with the findings of the subgroup analysis of geographic regions, most likely indicating that in addition to individual SES, regional SES differences, especially between the developed countries and developing countries, may also have an influence on the risk of CHDsSeveral limitations of our study should be considered. First, a total of 31 case-control studies and 2 cohort studies were recruited in our meta-analysis, and we extracted our raw data principally from case-control studies, which are susceptible to selection and information biases. Therefore, our results cannot be viewed as an inevitable relationship, and further investigations including more high-quality studies are needed. Second, our meta-analysis was limited to studies published in English, but no evidence of publication bias was found, whereas heterogeneity exists in the component studies. This finding may reflect the differences among study designs and study populations as well as other unknown factors associated with the included studies. Moreover, as our study was limited to English-language publications, our results may have been affected by the lack of data from studies published in other languages, especially in the middle- or low-income countries, where SES may be associated with CHDs. Therefore, any general conclusions must be considered carefully. The third limitation of our meta-analysis is the possible differences in the classification and definition of SES among the examined studies. Countries' overall economic and educational levels have a significant impact on the SES categories of maternal educational achievement, family income and maternal occupational prestige. Meanwhile, family income cannot strictly be reported as a solely maternal characteristic and we used it to instead of maternal income, which would bring confounding factors. Finally, our small sample size for family income and maternal occupation levels may have been underpowered to detect any influence of SES on the risk of CHD. Additionally, lacking a large set of data, we did not conduct a subgroup analysis of CHD subtypes.However, our study offers several important strengths. Due to the difficulty of evaluating the socioeconomic level and the lack of sufficient available literature, no meta-analysis had previously been performed to investigate the association of maternal SES with the risk of CHDs. Therefore, to our knowledge, this is the first meta-analysis to report an association between maternal SES and CHDs, including more than 50,000 cases. Moreover, our literature search was conducted on multiple databases, and the references in the relevant retrieved and review articles were fully scrutinized to obtain the missing data. Moreover, both Egger's linear regression and Begg's rank correlation tests showed no significant publication bias.In summary, this study provides evidence of an association between low SES and an increased risk of CHDs, including maternal educational attainment, family income and maternal occupational prestige, whereas no clear relationship was found between socioeconomic status and CHDs in developed countries. Our findings could make public health policy focus more strongly on at-risk populations and could be used in the development of population-based prevention strategies to reduce the incidence and burden of CHDs, particularly for the regions with a lower level of economic development. Moreover, as previous studies have found a correlation between educational level and CHD risk factors Checklist S1PRISMA checklist.(DOC)Click here for additional data file.