Association of three single nucleotide polymorphisms in interleukin 6 gene with risk of chronic obstructive pulmonary disease

Abstract

BackgroundsExperimental studies have implicated the involvement of interleukin 6 (IL6) in chronic obstructive pulmonary disease (COPD), supporting the possible association between genetic alterations in IL6 gene and risk of COPD. ObjectivesWe aimed to examine the association of three polymorphisms in IL6 gene with COPD by integrating the summary results of available reports, and summarize the changes circulating IL6 concentrations across genotypes. MethodsTwo investigators independently searched medical literature, selected qualified publications, assessed study quality, and abstracted detailed information. STATA software v14.1 was applied for statistical analyses. ResultsTen articles, including 18 independent studies and 4 815 participants, were comprehensively pooled. When all studies were analyzed together, the association with COPD was not significant for rs1800795 and rs1800797, yet statistical significance was attained for rs1818879 (P < 0.05) across four genetic modes of inheritance. When analyses were restricted to preset subgroups, race, matched condition, and COPD diagnosis were identified as the factors attributed to heterogeneity between studies. Moreover, changes in circulating IL6 concentrations remained nonsignificant across the genotypes of rs1800795 and rs1818879 (P > 0.05). Funnel plots and related tests revealed a low likelihood of publication bias for three studied polymorphisms (P > 0.1). ConclusionsOur findings indicated that IL6 gene rs1818879 might be a COPD-susceptibility locus. Further validations in longitudinal studies are necessary.