Association between the TGF-β1 polymorphisms and chronic obstructive pulmonary disease: a meta-analysis

It has been hypothesized that polymorphisms in the transforming growth factor-β1 (TGF-β1) gene on chromosome 19 modify the risk for chronic obstructive pulmonary disease (COPD). However, results from previous studies are contradictory. We therefore conducted a meta-analysis of published case-control studies on the association between five common TGF-β1 polymorphisms (rs1982073, rs1800469, rs2241712, rs6957, and rs2241718) and COPD risk. Data sources were Pubmed, Scopus, ISI Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases. Twelve studies including 6749 participants were reviewed and analyzed. For the TGF-β1 polymorphism rs1982073, the results indicted that the C allele was associated with decreased risk of COPD in Caucasians (odds ratio (OR) =0.79, 95% confidence interval (CI): 0.64-0.99, P=0.038) but not in Asians (OR =0.95, 95% CI: 0.71-1.28, P=0.741). No associations with COPD were identified for other polymorphisms evaluated in the present study including rs1800469 (T allele compared with C allele, OR =0.89, 95% CI: 0.77-1.02, P=0.099), rs2241712 (A allele compared with G allele, OR =1.03, 95% CI: 0.89-1.20, P=0.666), rs6957 (A allele compared with G allele, OR =1.14, 95% CI: 0.95-1.36, P=0.160), and rs2241718 (C allele compared with T allele, OR =0.95, 95% CI: 0.79-1.14, P=0.571). In conclusion, this meta-analysis showed that the C allele of rs1982073 was protective against COPD in Caucasians but not in Asians, whereas there was no association of rs1800469, rs2241712, rs6957, and rs2241718 with COPD.