and polymorphisms are associated with COPD risk: a systematic review and meta-analysis.

Chronic obstructive pulmonary disease (COPD) affects approximately 400 million people worldwide and is associated with high mortality and morbidity. The effect of and gene polymorphisms on COPD risk has not been fully characterized. To investigate the association of and polymorphisms with COPD risk. A systematic search was conducted on 9 databases to identify studies published in English and Chinese. The analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines (PRISMA). The pooled OR and 95% CI were calculated to evaluate the association of and polymorphisms with COPD risk. The I test, Q test, Egger's test, and Begg's test were conducted to determine the level of heterogeneity and publication bias of the included studies. In total, 857 articles were retrieved, among which 59 met the inclusion criteria. The rs1051740 polymorphism (homozygote, heterozygote, dominant, recessives, and allele model) was significantly associated with high risk of COPD risk. Subgroup analysis revealed that the rs1051740 polymorphism was significantly associated with COPD risk among Asians (homozygote, heterozygote, dominant, and allele model) and Caucasians (homozygote, dominant, recessives, and allele model). The rs2234922 polymorphism (heterozygote, dominant, and allele model) was significantly associated with a low risk of COPD. Subgroup analysis showed that the rs2234922 polymorphism (heterozygote, dominant, and allele model) was significantly associated with COPD risk among Asians. The rs1695 polymorphism (homozygote and recessives model) was significantly associated with COPD risk. Subgroup analysis showed that the rs1695 polymorphism (homozygote and recessives model) was significantly associated with COPD risk among Caucasians. The rs1138272 polymorphism (heterozygote and dominant model) was significantly associated with COPD risk. Subgroup analysis suggested that the rs1138272 polymorphism (heterozygote, dominant, and allele model) was significantly associated with COPD risk among Caucasians. The C allele in rs1051740 among Asians and the CC genotype among Caucasians may be risk factors for COPD. However, the GA genotype in rs2234922 may be a protective factor against COPD in Asians. The GG genotype in rs1695 and the TC genotype in rs1138272 may be risk factors for COPD, especially among Caucasians.