Introduction:
The gene encoding the β₂-adrenergic receptor (ADRB2) is a candidate gene for chronic obstructive pulmonary disease (COPD), yet the results are not often reproducible. We aimed to assess the association of ADRB2 genetic polymorphisms (rs1042713, rs1042714, and rs1800888) with COPD risk and COPD-related phenotypes via a meta-analysis.

Material and methods:
Literature search, quality evaluation, and data extraction were completed independently and in duplicate. Effect-size estimation is expressed as the odds ratio (OR) or weighted mean difference (WMD) with a 95% confidence interval (CI)

Results:
In total 15 articles were meta-analyzed, including 12 articles (2917/8807 patients/controls) for COPD risk, and 6 articles (18350 subjects) for COPD-related phenotypes. Overall, there was no detectable significance for the association of rs1042713 (OR, 95% CI: 1.02, 0.88–1.19) and rs1042714 (1.01, 0.85–1.20) with COPD risk, and only marginal significance retained for rs1800888 (1.31, 1.00–1.72). In subsidiary analyses, the association of rs1042713 and rs1042714 with COPD risk was significant in populations of Asian origin (OR: 1.66 and 1.351, 95% CI: 1.13–2.44 and 1.02–1.79). Additionally, carriers of rs1042713 AA genotype had significantly lower levels of FEV1 (WMD, 95% CI: –0.011 L, –0.026 to –0.004) than carriers of GG genotypes, and FVC% predicted levels were significantly higher for rs1042713 AA genotype (6.914, 4.829 to 8.999) and AG genotype (4.249, 2.925–5.573) compared with GG genotype. There were low probabilities of publication bias.

Conclusions:
Our findings suggest that the contribution of ADRB2 genetic polymorphisms to COPD risk is small and ethnicity-dependent, and to COPD-related phenotypes is significant.