Combined effect of five single nucleotide polymorphisms related to IL23/Th17 pathway in the risk of psoriasis

Psoriasis is a common immune-mediated inflammatory skin disease with strong genetic components, in which the IL23/Th17 pathway has been implicated. To explore the effective role in psoriasis, we genotyped five single nucleotide polymorphisms in genes related to IL23/Th17 pathway in 14,929 Han Chinese samples. A Bonferroni-corrected significant single-variant association was identified between rs1512970 within IL21 (odds ratio (OR)?=?1.07, 95 % confidence interval (CI)?=?1.02–1.13, P?=?4.94?×?10^?03). We failed to validate rs744166 (OR?=?1.06, 95 % CI?=?1.01–1.11, P?=?1.52?×?10^?02) and other three SNPs (P?=?2.48?×?10^?01?～?1.27?×?10^?02) to meet the single-variant association significance threshold. However, we found that their combined effect substantially contributed to the risk of psoriasis in our sample (P?=?3.91?×?10^?07) and the highest score group conferred the largest risk effect size (OR?=?1.22, 95 % CI?=?1.11–1.34, P?=?1.85?×?10^?05). Our results implicate the ethnic heterogeneity in the susceptibility of psoriasis and suggest common variants with weak effect in IL23/Th17 pathway, which do not show significance in conventional single-variant association study, may contribute to the risk of psoriasis. This study sheds light on the important role of IL23/Th17 pathway in the susceptibility of psoriasis.     

Two Novel Susceptibility SNPs for Ischemic Stroke Using Exome Sequencing in Chinese Han Population

Genome-wide association studies (GWAS) of ischemic stroke (IS) have been performed on several cohorts of Caucasian or African population and Japanese, resulting in somewhat inconsistent conclusion. We aimed to identify susceptibility loci for IS by exome sequencing in a Chinese Han population. Exome sequencing was used to screen susceptibility loci among 100 cases and 100 matched controls. Significant SNPs from the first stage were verified in up to 3,554 participants from three hospital-based case–control studies. In the initial exome sequencing analysis, rs10489177 in c1orf156 gene located on chromosome 1q24 (p?<?1?×?10^?8) and rs17118 in XYLB gene located on chromosome 3p21 (p?<?1?×?10^?6) were found to be significantly associated with IS. In the following validation stage, significantly increased odds ratios were observed in individuals with rs10489177 GG (OR?=?2.02, 95 % CI?=?1.35–3.03) or rs17118 AA genotype (OR?=?1.50, 95 % CI?=?1.17–1.91). The rs10489177 GG genotype was associated with significantly increased risk for IS in individuals without hypertension (OR?=?2.78, 95 % CI?=?1.59–4.86) and in individuals without diabetes (OR?=?1.93, 95 % CI?=?1.27–2.94). In contrast, the rs17118 AA genotype may significantly increase the risk for IS, particularly for individuals with hypertension (OR?=?1.73, 95 % CI?=?1.08–2.78) and for individuals without diabetes (OR?=?1.52, 95 % CI?=?1.17–1.98) or non-smoker (OR?=?1.59, 95 % CI?=?1.16–2.19). Collectively, our study identified two novel loci (rs17118 and rs10489177) which were associated with an increased risk for IS in Chinese Han populations. Further studies are needed to confirm these associations in other populations and elucidate the biological mechanisms underlying the observed associations.     

Analyzing Large-Scale Samples Confirms the Association Between the ABCA7 rs3764650 Polymorphism and Alzheimer’s Disease Susceptibility

Large-scale genome-wide association studies (GWAS) have revealed that the ABCA7 rs3764650 polymorphism (or its proxies, namely rs115550680, rs3752246, and rs4147929) is associated with Alzheimer’s disease (AD) susceptibility in individuals of Caucasian ancestry. The following studies have investigated this finding in Chinese (N?=?633 and N?=?1,224), Japanese (N?=?1,735), Korean (N?=?844), African American (N?=?5,896), and Canadian (N?=?1,104) populations. However, these studies reported a weak or negligible association. We hypothesized that these negative results may have been caused by either relatively small sample sizes compared with those used for the previous GWAS in individuals of Caucasian ancestry or the genetic heterogeneity of the rs3764650 polymorphism (or its proxies) in different populations. Here, we reevaluated the association between rs3764650 and AD using large-scale samples from 18 previous studies (N?=?79,381—30,590 cases and 48,791 controls) by searching PubMed, AlzGene, and Google Scholar databases. Using allele, dominant, recessive, and additive models, we did not identify significant heterogeneity among the 18 studies. We observed a significant association between rs3764650 and AD using the allele (P?=?1.76E???26, odds ratio (OR)?=?1.21, 95 % confidence interval (CI) 1.17–1.26), dominant (P?=?4.00E???04, OR?=?1.17, 95 % CI 1.07–1.28), recessive (P?=?3.00E???03, OR?=?1.43, 95 % CI 1.13–1.81), and additive models (P?=?3.00E???03, OR?=?1.49, 95 % CI 1.16–1.91). Collectively, our analysis further supports previous findings that the ABCA7 rs3764650 polymorphism is associated with AD susceptibility. We believe that our findings will be very useful for future genetic studies on AD.     

SORL1 Is Associated with the Risk of Late-Onset Alzheimer’s Disease: a Replication Study and Meta-Analyses

The sorting-related receptor gene (SORL1) has been defined as an interesting candidate gene for Alzheimer’s disease (AD). Recently, one novel variant, rs11218343, within SORL1 was reported to be related to late-onset Alzheimer’s disease (LOAD) in Caucasians, Korean, and Japanese. The aim of this case–control study is to investigate whether SORL1 rs11218343 contributes to susceptibility for LOAD in Chinese. Furthermore, our data, along with previously studies, were pooled for determining the risk of the rs11218343 polymorphism on LOAD. The rs11218343 polymorphism was genotyped in the 2350 independent subjects from Northern Han Chinese population (including 992 cases and 1358 age- and gender-matched controls). Result of the case–control study showed the association between rs11218343 polymorphism and the risk of LOAD in a Northern Han Chinese population (recessive model: odds ratio (OR)?=?0.641, 95 % confidence interval (CI)?=?0.464–0.884, P?=?0.007; additive model: OR?=?0.873, 95 % CI?=?0.765–0.996, P?=?0.043). The results of meta-analysis in subgroups (Caucasian and Asian) and the whole showed that the minor allele (C allele) within rs11218343 played a protective effect on AD risk (OR (95 % CI), 0.77 (0.72–0.83), 0.85 (0.79–0.91), 0.81 (0.76–0.85), respectively). In conclusion, the C allele in SORL1 rs11218343 may be a protective factor for LOAD in both Caucasian and Han Chinese.     

Association of functional polymorphisms in the MxA gene with susceptibility to enterovirus 71 infection

Myxovirus resistance A (MxA) is an antiviral protein induced by type I interferons α and β (IFN-α and IFN-β) that can inhibit virus replication. We examined whether the MxA polymorphisms were related to the risk and severity of enterovirus 71 (EV71) infection in Chinese populations. The MxA C-123A and G-88T polymorphisms were genotyped in two independent case–control populations in China by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) analysis. Multivariate logistic regression analysis was used to calculate adjusted odds ratios (ORs) and 95 % confidence intervals (95 % CIs). MxA messenger RNA was quantified by real-time quantitative PCR in peripheral blood mononuclear cells (PBMCs) from 45 healthy children and 19 patients with EV71 infection. Significantly decreased susceptibility to EV71 infection was observed for the -123A allele and -88T allele carriers, with ORs (95 % CIs) estimated as 0.56 (0.39–0.81) and 0.64 (0.47–0.88), respectively, in the northern population. This association was confirmed in the southern population, with ORs (95 % CIs) estimated as 0.58 (0.38–0.89) and 0.67(0.47–0.95), respectively. The A_{- 123}T_{- 88} haplotype was also significantly associated with lower risk of EV71 infection in both the northern (OR = 0.62; 95 % CI = 0.44–0.85) and the southern population (OR = 0.63; 95 % CI = 0.43–0.92). Furthermore, we observed higher MxA messenger RNA levels in IFNβ1a-stimulated PBMCs from the -123A or -88T allele carriers compared with that from nocarriers. Our findings suggest that polymorphisms in the MxA promoter may play a role in mediating the susceptibility to EV71 infection in Chinese population.     

Significant association between GSTT1 null genotype and risk of asthma during childhood in Caucasians

Asthma is a complex multifactorial disorder and its management requires a better understanding of its various pathogenesis and mechanisms. Previous studies assessing the association between glutathione S-transferase T1 (GSTT1) null genotype and asthma risk during childhood reported conflicting results. To get a more precise estimation of the association between GSTT1 null genotype and risk of asthma during childhood, we performed a meta-analysis of 16 studies with a total of 18,558 subjects. Subgroup analyses were performed by ethnicity. The pooled odds ratio (OR) with corresponding 95 % confidence interval (95 %CI) was used to assess the association. Overall, there was a significant association between GSTT1 null genotype and increased risk of children asthma (OR = 1.25, 95 % CI, 1.02–1.54; P = 0.032). Subgroup analyses showed GSTT1 null genotype was associated with increased risk of children asthma in Caucasians (OR = 1.46, 95 % CI, 1.04–2.03; P = 0.027), but not in Asians (OR = 1.03, 95 % CI, 0.55–1.94; P = 0.928) and Africans (OR = 1.33, 95 % CI, 0.92–1.91; P = 0.127). There was no evidence of publication bias in the subgroup analysis of Caucasians. In conclusion, there is a significant association between GSTT1 null genotype and risk of asthma during childhood in Caucasians. More well-designed epidemiological studies are needed to further assess this association in Asians and Africans.     

Effects of Pharmacological Concentrations of Dietary Zinc Oxide on Growth of Post-weaning Pigs: A Meta-analysis

Pharmacological dietary zinc (Zn) concentrations of 1,000 to 3,000 mg/kg diet from Zn oxide have been found to increase growth in post-weaning pigs. However, results were inconsistent among studies. A frequentist meta-analysis, in which effects were numerically described with standardized effect sizes (Hedges's g), was conducted in order to identify and quantify the responses in average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G/F) in post-weaning pigs upon dietary Zn supplementation from Zn oxide. The inability of independent continuous variables to explain significant heterogeneity obtained with fixed effect models necessitated the use of random effects models to calculate summary statistics. Dietary Zn supplementation increased (P?<?0.05) ADG (mean effect size?=?1.086, 95 % confidence intervals?=?0.905–1.266, 26 studies, 72 comparisons), ADFI (mean effect size?=?0.794, 95 % confidence intervals?=?0.616–0.971, 25 studies, 71 comparisons), and G/F (mean effect size?=?0.566, 95 % confidence intervals?=?0.422–0.710, 24 studies, 70 comparisons). Zinc oxide provided a feasible alternative to in-feed antibiotics to improve growth in post-weaning pigs, and its reduction in diets due to potential environmental pollution will have to be negated by alternative feed additives and management strategies in order to prevent economic losses.     

Gene–environment interactions between <Emphasis Type="Italic">ERCC2</Emphasis>, <Emphasis Type="Italic">ERCC3</Emphasis>, <Emphasis Type="Italic">XRCC1</Emphasis> and cadmium exposure in nasal polyposis disease

Gene–environment interactions have long been known to play an important role in complex disease aetiology, such as nasal polyposis (NP). The present study supports the concept that DNA repair gene polymorphisms play critical roles in modifying individual susceptibility to environmental diseases. In fact, we investigated the role of polymorphisms in DNA repair genes and cadmium as risk factors for Tunisian patients with NP. To the best of our knowledge, this is the first report on the impact of combined effects of cadmium and ERCC3 7122 A>G (rs4150407), ERCC2 Lys751Gln (rs13181) and XRCC1 Arg399Gln (rs25487) genes in the susceptibility to NP disease. Significant associations between the risk of developing NP disease and ERCC2 [odds ratio (OR)?=?2.0, 95 % confidence interval (CI)?=?1.1–3.7, p?=?0.023] and ERCC3 (OR?=?2.2, 95 % CI?=?1.2–4.1, p?=?0.013) genotypes polymorphisms were observed. Blood concentrations of Cd in NP patients (2.2 μg/L) were significantly higher than those of controls (0.5 μg/L). A significant interaction between ERCC3 (7122 A>G) polymorphism and blood-Cd levels (for the median of blood-Cd levels: OR?=?3.8, 95 % CI?=?1.3–10.8, p?=?0.014 and for the 75th percentiles of blood-Cd levels: OR?=?2.7, 95 % CI?=?1.1–7.2, p?=?0.041) was found in association with the risk of NP disease. In addition, when we stratified ERCC2, ERCC3 and XRCC1 polymorphism genotypes by the median and 75th percentiles of blood-Cd levels, we found also significant interactions between ERCC2 (Lys751Gln) and ERCC3 (7122 A>G) genotypes polymorphism and this metal in association with NP disease. However, no interaction was found between XRCC1 (Arg399Gln) polymorphism genotypes and Cd in association with NP disease.     

Association Between Circulating Copeptin Level and Mortality Risk in Patients with Intracerebral Hemorrhage: a Systemic Review and Meta-Analysis

Copeptin has been identified as a biomarker of disease severity and is associated with mortality risk in several common diseases. This study sought to determine the association between circulating copeptin level and mortality risk in patients with intracerebral hemorrhage. PubMed, Web of Science, and Wanfang Medicine Database were searched for studies assessing the association between circulating copeptin level and mortality risk in patients with intracerebral hemorrhage. The pooled hazard ratio (HR) of mortality was calculated and presented with 95 % confidence interval (95 % CI). Data from 1332 intracerebral hemorrhage patients were derived from 9 studies. Meta-analysis showed that intracerebral hemorrhage patients with poor prognosis had much higher copeptin levels than those survivors (standardized mean difference?=?1.68, 95 % CI 1.26–2.11, P?<?0.00001). Meta-analysis of 8 studies with HRs showed that high circulating copeptin level was associated with higher risk of mortality in patients with intracerebral hemorrhage (HR?=?2.42, 95 % CI 1.60–3.65, P?<?0.0001). Meta-analysis of 6 studies with adjusted HRs showed that high circulating copeptin level was independently associated with higher risk of mortality in patients with intracerebral hemorrhage (HR?=?1.67, 95 % CI 1.26–2.22, P?=?0.0003). Our study suggests that there is an obvious association between circulating copeptin level and mortality in patients with intracerebral hemorrhage. High circulating copeptin level is independently associated with higher risk of mortality in patients with intracerebral hemorrhage.     

Genetic polymorphisms in VDR,ESR1 and ESR2 genes may contribute to susceptibility to Parkinson’s disease: a meta-analysis

We conducted this meta-analysis of relevant case–control studies to investigate the relationships between genetic polymorphisms in VDR, ESR1 and ESR2 genes to the susceptibility of Parkinson’s disease (PD). A search on electronic databases without any language restrictions was conducted: MEDLINE (1966–2013), the Cochrane Library Database (Issue 12, 2013), EMBASE (1980–2013), CINAHL (1982–2013), Web of Science (1945–2013) and the Chinese Biomedical Database (1982–2013). Meta-analysis was performed using the STATA statistical software. Crude odds ratio (OR) with their 95 % confidence interval (95 % CI) was calculated. Fourteen case–control studies with a total of 3,689 PD patients and 4,627 healthy subjects were included in our meta-analysis. The results of our meta-analysis demonstrated that the VDR genetic polymorphisms might be closely related to increased risks of PD (allele model: OR = 1.18, 95 % CI 1.09–1.29, P < 0.001; dominant model: OR = 1.37, 95 % CI 1.16–1.63, P < 0.001; respectively), especially for the polymorphisms rs7976091 and rs10735810. Our findings also illustrated that ESR1 genetic polymorphisms might increase the risk of PD (allele model: OR = 1.56, 95 % CI 1.17–2.07, P = 0.002; recessive model: OR = 1.93, 95 % CI 1.33–2.80, P < 0.001; homozygous model: OR = 1.35, 95 % CI 1.02–1.79, P = 0.038; heterozygous model: OR = 2.04, 95 % CI 1.36–3.07, P = 0.001; respectively), especially for the polymorphisms rs2234693 and rs9340799. Furthermore, we found significant correlations of ESR2 genetic polymorphisms with the risk of PD (allele model: OR = 1.78, 95 % CI 1.19–2.67, P = 0.005; recessive model: OR = 1.93, 95 % CI 1.15–3.27, P = 0.014; homozygous model: OR = 1.77, 95 % CI 1.09–2.89, P = 0.022; heterozygous model: OR = 1.88, 95 % CI 1.08–3.27, P = 0.025; respectively), especially for the rs1256049 polymorphism. Our meta-analysis suggests that genetic polymorphisms in VDR, ESR1 and ESR2 genes may contribute to increased risks for PD.     

Relationships between PON1 Q192R polymorphism and clinical outcome of antiplatelet treatment after percutaneous coronary intervention: a meta-analysis

This meta-analysis was performed to assess the relationships between the PON1 Q192R (rs662 T>C) polymorphism and the clinical outcome of antiplatelet treatment after percutaneous coronary intervention (PCI). A range of electronic databases were searched: Web of Science (1945–2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966–2013), EMBASE (1980–2013), CINAHL (1982–2013) and the Chinese Biomedical Database (CBM) (1982–2013) without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. The crude odds ratio (OR) with their 95 % confidence interval (CI) were calculated. Six clinical cohort studies with a total number of 5,189 patients undergoing PCI for coronary heart disease were included. Our meta-analysis revealed that the PON1 Q192R polymorphism was correlated with an increased risk of major adverse cardiovascular events (MACE) in patients receiving antiplatelet treatment after PCI (C allele vs. T allele: OR = 1.22, 95 % CI 1.04–1.43, P = 0.014; CT+CC vs. TT: OR = 1.38, 95 % CI 1.03–1.86, P = 0.029; CC vs. TT: OR = 1.45, 95 % CI 1.05–1.99, P = 0.024; respectively), especially among Asians. Furthermore, we found significantly positive correlations between the PON1 Q192R polymorphism and the incidence of stent thrombosis in patients receiving antiplatelet treatment after PCI (C allele vs. T allele: OR = 1.42, 95 % CI 1.08–1.87, P = 0.011; CT+CC vs. TT: OR = 1.93, 95 % CI 1.01–3.67, P = 0.046; CC vs. TT: OR = 2.18, 95 % CI 1.09–4.35, P = 0.027; respectively). Our meta-analysis of clinical cohort studies provides evidence that the PON1 Q192R polymorphism may increase the risk of MACE and stent thrombosis in patients receiving antiplatelet treatment after PCI.     

Significant association between GSTT1 null genotype and susceptibility to pancreatic cancer

Many studies have investigated the association between glutathione S-transferase T1 (GSTT1) polymorphism and risk for pancreatic cancer, but those studies have yielded contradictory findings on the association. We performed a comprehensive search in the PubMed, EMBASE, and the Chinese National Knowledge Infrastructure databases to identify relevant studies. A meta-analysis was performed to examine the association between GSTT1 polymorphism and susceptibility to pancreatic cancer by calculating the pooled odds ratios (ORs) and corresponding 95 % confidence intervals (95 % CIs). Eight studies involving a total of 4,437 individuals were included. Overall, significantly increased pancreatic cancer risk was associated with GSTT1 null genotype when all studies were pooled into the meta-analysis (random effects OR = 1.61, 95 % CI 1.06–2.44; P = 0.025). Significantly increased risk of pancreatic cancer was also found for GSTT1 null genotype in Asians when stratified by ethnicity (fixed effects OR = 2.67, 95 % CI 1.74–4.09; P < 0.001). The findings demonstrate that GSTT1 null genotype have a modest effect on the genetic susceptibility to pancreatic cancer, and GSTT1 null genotype is associated with increased risk of pancreatic cancer.     

The Impact of MMP-2 and Its Specific Inhibitor TIMP-2 Expression on the WHO Grade and Prognosis of Gliomas in Chinese Population: a Meta-Analysis

So far, the prognostic value of matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of matrix metalloproteinase 2 (TIMP-2) expressions in patients with gliomas has been widely reported, especially in China. But, the results were inconsistent. Thus, we conducted a meta-analysis to determine the correlation of MMP-2 and TIMP-2 expressions with the prognosis of patients with gliomas. Identical search strategies were used to search relevant literature in electronic databases updated to May 1, 2015, and odds ratios (ORs) with 95 % confidence intervals (95 % CIs) were estimated. Funnel plots and Egger’s tests were conducted for the evaluation of publication bias, and heterogeneity and sensitivity were also analyzed. Finally, a total of 25 studies involving 1572 patients were included in the meta-analysis. Coincidentally, all these studies were conducted in Chinese population. It was found that MMP-2 expression was significantly associated with high-WHO grade gliomas (n?=?24, OR?=?6.54, CI?=?4.98–8.60; I ²?=?0 %, P?=?0.911) and poor overall survival (OS), while it did not correlate to age (n?=?2, OR?=?0.78, CI?=?0.35–1.74; I ²?=?0 %, P?=?0.621) and gender (n?=?2, OR?=?1.15, CI?=?0.51–2.62; I ²?=?0 %, P?=?0.995). Moreover, the results of the pooled analysis indicated that there was no association between TIMP-2 expression and the WHO grade of gliomas (n?=?7, OR?=?1.02, 95 % CI?=?0.68–1.54; I ²?=?71.4 %, P?=?0.002), but the ratio of MMP-2 and TIMP-2 (MMP-2/TIMP-2) rose with the increase of the WHO grade of gliomas. In conclusion, there was no correlation between TIMP-2 expression and the WHO grade of gliomas, while MMP-2 expression was potently associated with high-WHO grade of gliomas.     

VEGF +936C/T and +460C/T gene polymorphisms and oral cancer risk: a meta-analysis

Many studies have examined the association between the VEGF +936C/T (rs833061) and +460C/T (rs3025039) gene polymorphisms and oral cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, we performed a meta-analysis. The PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases were searched for case–control studies that were published up to January 2013. Data were extracted and pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated. Ultimately, six studies were included, comprising 1006 oral cancer cases and 1016 controls. Overall, the pooled OR for VEGF +936 T allele carriers (TC + TT) versus the wild-type homozygotes (CC) was 1.28 (95 % CI 1.04–1.58; P = 0.228 for heterogeneity), the pooled OR for TT versus CC was 1.64 (95 % CI 1.34–1.98; P = 0.315 for heterogeneity), and the pooled OR for the T allele versus the C allele was 1.42 (95 % CI 1.22–1.76; P = 0.286 for heterogeneity). In the stratified analysis by ethnicity, significant risks were found among Caucasians but not Asians. However, there were no associations between VEGF +460C/T and oral cancer risk in only two of the included studies. In conclusion, this meta-analysis demonstrates that the VEGF +936 T allele may be associated with an increased risk of oral cancer, especially among Caucasian populations.     

Significant association of glutathione S-transferase T1 null genotype with esophageal cancer risk: a meta-analysis

Recent studies on the association between glutathione S-transferase T1 (GSTT1) polymorphism and risk of esophageal cancer showed inconclusive results. To clarify this possible association, we conducted a meta-analysis of published studies. Data were collected from the following electronic databases: Pubmed, Embase, and Chinese Biomedical Database (CBM). The odds ratio (OR) and its 95 % confidence interval (95 % CI) was used to assess the strength of this association. We summarized the data on the association between GSTT1 null genotype and risk of esophageal cancer in the overall population, and performed subgroup analyses by ethnicity. Finally, a total of 24 independent studies including a total of 7,801 subjects (2,965 cases and 4,836 controls) were eligible for meta-analysis. In the overall analysis, there was no significant association between GSTT1 null genotype and esophageal cancer risk (OR = 1.15, 95 % CI 0.99–1.33, P = 0.067). However, meta-analysis of adjusted ORs showed a significant association between GSTT1 null genotype and increased risk of esophageal cancer (OR = 1.30, 95 % CI 1.08–1.56, P = 0.005). Subgroup analyses by ethnicity showed there was an obvious association between GSTT1 null genotype and increased risk of esophageal cancer in East Asians (OR = 1.24, 95 % CI 1.10–1.39, P < 0.001), but not in Caucasians (OR = 0.89, 95 % CI 0.71–1.11, P = 0.300). There was no obvious risk of publication bias in this meta-analysis (Egger’s test, P = 0.784). This meta-analysis demonstrates that GSTT1 null genotype is independently associated with increased risk of esophageal cancer, and a race-specific effect may exist in this association.     

MDR1 C3435T polymorphism and inflammatory bowel disease risk: a meta-analysis

The C3435T polymorphism of the multidrug resistance gene (MDR1) has been implicated in inflammatory bowel disease (IBD) risk, but the reported results are inconsistent. Here we performed a meta-analysis to evaluate the association between C3435T polymorphism and the risk of IBD using all case–control studies published before February 2013 according to PubMed and Web of Science. A total of 13 case–control studies, including 6,757 cases and 4,295 controls, were included. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated using fixed- or random-effects model. Overall, no evidence has indicated that the C3435T polymorphism was associated with the susceptibility to IBD (dominant model: OR = 1.05, 95 % CI: 0.96–1.16; CT vs. CC: OR = 1.06, 95 % CI: 0.95–1.17; TT vs. CC: OR = 1.04, 95 % CI: 0.92–1.17; recessive model: OR = 0.99, 95 % CI: 0.90–1.09). Besides, stratified analysis by clinical type also indicated that no significant association between MDR1 C3435T and the risk of Crohn’s disease and ulcerative colitis was observed. This meta-analysis indicated that the C3435T polymorphism of MDR1 may not confer susceptibility to IBD.     

Meta-analysis of the association between common interleukin-1 polymorphisms and dental implant failure

Interleukin-1 (IL) plays a pivotal role in immune–inflammatory response that maintains periodontal homeostasis. A number of epidemiological studies have been conducted to investigate the associations between common polymorphisms of IL-1 (IL-1A, IL-1B) genes and risk of peri-implant disease, but the findings remain inconclusive. Thirteen studies evaluating the association between IL-1 polymorphisms and risk for peri-implant diseases (implant failure/loss, peri-implantitis) were included. Fixed model or random-effects models were applied to calculate overall and ethnicity-specific summary odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) as risk estimates for IL-1 polymorphisms individually or in combination. Heterogeneity and publication bias were evaluated by Q-test, I ² statistic, Begg’s funnel plot and Egger’s test accordingly. The composite genotype of IL-1A (?889) and IL-1B (+3954) was associated with increased risk of implant failure/loss (OR 1.76, 95 % CI 1.21–2.57) and peri-implantitis (OR 2.34, 95 % CI 1.03–5.33). The significance was borderline in European descents (implant failure/loss: OR 1.48, 95 % CI 0.99–2.22; peri-implantitis: OR 1.65, 95 % CI 1.00–2.73). T allele of IL-1B (?511) was associated with increased risk of implant failure/loss (OR 1.28, 95 % CI 1.01–1.62), while the association was not significant in European descents (OR 1.12, 95 % CI 0.85–1.48). These findings support a potential role of IL-1 polymorphisms, particularly the composite genotype of IL-1A (?889) and IL-1B (+3954), in peri-implant disease susceptibility. More studies with large sample size are needed to validate the associations.     

Association between polymorphism of MTHFR c.677C>T and risk of cardiovascular disease in Turkish population: a meta-analysis for 2.780 cases and 3.022 controls

Cardiovascular diseases (CVDs) remain the main cause of morbidity and mortality around the world. A common polymorphism c.677C>T has been identified in the gene coding for methylenetetrahydrofolate reductase (MTHFR), which is involved in the remethylation of homocysteine, and may predispose to CVDs. A meta-analysis was performed to estimate the risk of CVDs associated with MTHFR c.677C>T in Turkish population. Published studies were retrieved from PubMed, Science Citation Index/Expanded, Google Scholar, Turkish Medline, and the Turkish Council of Higher Education Theses Database. For each study, we calculated odds ratios and 95 % confidence intervals (CI), assuming frequency of allele and homozygote comparison, dominant and recessive genetic models. Thirty-one separate studies were included and 2.780 cases/3.022 controls were involved in the current meta-analysis. Significant association was found between c.677C>T polymorphism and risk of CVD when all studies pooled with random-effects model for T versus C (OR 1.33; 95 % CI 1.11–1.59; p = 0.002), TT vs. CC (OR 1.87; 95 % CI 1.35–2.60; p = 3.53E?04), TT+CT vs. CC (OR 1.32; 95 % CI 1.06–1.64; p = 0.014) and TT vs. CT+CC (OR 1.75; 95 % CI 1.29–2.37; p = 6.57E?04). Further analysis indicated the significant association between methylenetetrahydrofolate reductase (MTHFR) TT genotype and groups with venous thrombosis, peripheral arterial thrombosis, acute MI/MI. No publication bias was observed in any comparison model. Our results of meta-analysis suggest that MTHFR c.677C>T polymorphism is associated with the CVDs in Turkish population.     

Genetic variants at 4q21, 4q23 and 12q24 are associated with esophageal squamous cell carcinoma risk in a Chinese population

A recently published genome-wide association study (GWAS) in European populations identified several loci at 4q21, 4q23 and 12q24 that were associated with risk of upper aerodigestive tract (UADT) cancers, including esophageal squamous cell carcinoma (ESCC). In the current study, we conducted a case–control study in a Chinese population including 2,139 ESCC cases and 2,273 controls to evaluate the associations of six reported single nucleotide polymorphisms (SNPs) (rs1494961, rs1229984, rs1789924, rs971074, rs671 and rs4767364) with risk of ESCC. We found significant association with risk of ESCC for four SNPs, including rs1494961 in HEL308 at 4q21 [odds ratio (OR) = 1.15, 95 % confidence interval (CI) = 1.05–1.26], rs1229984 in ADH1B at 4q23 (OR = 1.24, 95 % CI = 1.13–1.36) and rs1789924 near ADH1C at 4q23 (OR = 1.20, 95 % CI = 1.03-1.39), and rs671 in ALDH2 at 12q24 (OR = 0.83, 95 % CI = 0.75–0.91). Combined analysis of these four SNPs showed a significant allele-dosage effect on ESCC risk for individuals with different number of risk alleles (P trend = 2.23 × 10^?11). Compared with individuals with “0–2” risk allele, those carrying “3”, “4” or “5 or more” risk alleles had 1.42-, 1.66-, or 1.76-fold risk of ESCC, respectively. Thus, our findings indicate that rs1494961 at 4q21, rs1229984 and rs1789924 at 4q23, and rs671 at 12q24 may be used as genetic biomarkers for ESCC susceptibility in Chinese population.     

Assessment of the association between GSTM1 null genotype and risk of type 2 diabetes

Many studies have investigated the association between Glutathione S-Transferase M1 (GSTM1) null genotype and risk of diabetes mellitus, but the impact of GSTM1 null genotype on diabetes mellitus is unclear owing to the obvious inconsistence among those studies. This study aimed to quantify the strength of association between GSTM1 null genotype and risk of diabetes mellitus. We searched the PubMed, Embase and Wangfang databases for studies relating the association between GSTM1 null genotype and risk of diabetes mellitus. We estimated summary odds ratio (OR) with their 95 % confidence interval (95 % CI) to assess the association. Subgroup analyses were performed by type of diabetes and ethnicity. 10 case–control studies with 7, 054 subjects were included into this meta-analysis. Meta-analysis of total 10 studies showed GSTM1 null genotype was associated increased risk of diabetes mellitus (OR = 1.59, 95 % CI 1.14–2.22, P = 0.007). Subgroup analyses by type of diabetes mellitus suggested GSTM1 null genotype was associated increased risk of type 2 diabetes (OR = 1.90, 95 % CI 1.37–2.64, P < 0.001), but was not associated with risk of type 1 diabetes (OR = 0.84, 95 % CI 0.66–1.07, P = 0.153). Subgroup analysis by ethnicity further identified the obvious association between GSTM1 null genotype and increased risk of type 2 diabetes. The cumulative meta-analyses showed a trend of obvious association between GSTM1 null genotype and risk of type 2 diabetes as information accumulated. No evidence of publication bias was observed. Thus, evidence from current meta-analysis suggests an association between GSTM1 null genotype and risk of type 2 diabetes.