Polymorphisms in a disintegrin and metalloprotease 33 gene and the risk of chronic obstructive pulmonary disease: A meta-analysis

A number of polymorphisms in a disintegrin and metalloprotease 33 (ADAM33) gene have been implicated in susceptibility to chronic obstructive pulmonary disease (COPD). However, results to date have been inconclusive. We conducted meta-analyses to investigate the associations between multiple polymorphisms in ADAM33 gene and COPD susceptibility. PubMed, Embase and Chinese databases (Wanfang and China National Knowledge Infrastructure) were searched for eligible case-control studies. We extracted data and used meta-analysis to calculate pooled odds ratios with 95% confidence intervals to evaluate the strength of associations. Twelve studies containing six ADAM33 polymorphisms (F+1, S1, S2, T1, V4 and Q-1) were identified, which involved 2630 cases and 4376 controls. ADAM33 S1 polymorphism showed stable and significant associations with COPD risks among the Chinese and smoking populations, and Q-1 polymorphism showed stable and significant associations with COPD risks among the overall populations. In subgroup analyses, T1 and Q-1 polymorphisms were significantly associated with COPD risks among the Chinese and smoking populations, and among the Chinese, Caucasians and smoking populations, respectively. However, none of the significant results was stable in sensitivity analyses. With respect to F+1, S2 or V4 polymorphism, there was no evidence of any significant association with COPD risks in either the overall or the subgroup analysis. The results of this meta-analysis indicate that ADAM33 S1 polymorphism is a risk factor for COPD among the Chinese and smoking populations, and that Q-1 polymorphism is a risk factor for COPD among the overall populations.