Association between V4 polymorphism in the ADAM33 gene and asthma risk: a meta-analysis.

In this study, we evaluated the associations between the V4 (rs2787094 G>C) polymorphism in a disintegrin and metalloproteinase domain 33 (ADAM33) gene and asthma risk. We searched Web of Science, PubMed, Google Scholar, EBSCO, Cochrane Library, and CBM databases from inception through August 2013, without language restrictions. Meta-analysis was performed using the STATA 12.0 software. Crude odds ratios and 95% confidence intervals were calculated. Eight case-control studies were included, with a total of 2128 asthma patients and 3134 healthy controls. Our results suggest that the ADAM33 V4 polymorphism increases the risk of asthma. Subgroup analysis according to the source of controls revealed significant associations between the ADAM33 V4 polymorphism and risk of asthma in population- and hospital-based subgroups under allele and dominant models (all P < 0.05). Further subgroup analysis using the genotyping method suggested that the ADAM33 V4 polymorphism is correlated with asthma risk in the polymerase chain reaction-restriction fragment length polymorphism subgroup. However, no association was found in the non-polymerase chain reaction-restriction fragment length polymorphism subgroup. Meta-regression analyses showed that the genotyping method may be a main source of heterogeneity (P = 0.003). Our meta-analysis suggests that the ADAM33 V4 polymorphism contributes to the risk of asthma and may be utilized as a biomarker for the early diagnosis of asthma.