Interleukin-1B-31T/C promoter polymorphism and chronic obstructive pulmonary disease risk: a meta-analysis

INTRODUCTION: The role of interleukin (IL)-1β –31T/C promoter polymorphism in the pathogenesis of chronic obstructive pulmonary disease (COPD) has been studied with inconsistent results. This meta-analysis was performed to assess the association of IL-1β –31T/C promoter polymorphism with COPD susceptibility. MATERIAL AND METHODS: Published case-control studies from PubMed and China National Knowledge Infrastructure (CNKI) databases were retrieved. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. RESULTS: Six case-control studies were included in this meta-analysis. The pooled effect size showed that IL-1β -31T/C was significantly associated with COPD susceptibility in an overdominant genetic model (CC+TT vs. TC, OR: 0.77, 95% CI: 0.63–0.94), indicating that homozygotes (CC and TT) had a decreased risk for COPD compared with heterozygotes (TC). In the subgroup analysis by ethnicity, the results indicated that IL-1β –31T/C was significantly correlated with COPD susceptibility in Asians (overdominant model, OR: 0.75, 95% CI: 0.61–0.93), further suggesting a protective role of IL-1β –31T/C in COPD pathogenesis in Asians. Moreover, after excluding the study without Hardy-Weinberg equilibrium, the pooled results were robust and no publication bias was found in this study. CONCLUSIONS: This meta-analysis suggests that IL-1β –31T/C promoter polymorphism confers protection against COPD in Asians.