Objectives:We conducted a meta-analysis of published studies on the
angiotensin-converting enzyme (ACE) gene insertion/deletion
(I/D) polymorphism associated with the risk of chronic obstructive pulmonary
disease, as well as with pulmonary function and circulating
angiotensin-converting enzyme changes.Methods:A literature search, quality assessment and data extraction were completed
independently and in duplicate.Results:A total of 16 articles were meta-analysed, including 12 articles (2113
patients and 8786 controls) for chronic obstructive pulmonary disease risk
and eight articles (11,664 subjects) for pulmonary and circulating
phenotypes. In overall and subgroup analyses, no significance was noted
between the I/D polymorphism and chronic obstructive pulmonary disease risk
under all genetic models (P>0.05), without heterogeneity
or publication bias. Carriers of II, ID and II plus ID genotypes had
significantly lower levels of circulating angiotensin-converting enzyme than
those with the DD genotype (weighted mean difference −13.35, −8.13 and
−10.74 U/L, respectively, P<0.001). For forced
expiratory volume in one second (FEV1)/forced vital capacity,
carriers of the DD genotype had marginally lower levels than those with the
DD genotype (weighted mean difference –1.66, P=0.034).
Furthermore in the case of FEV1 of 50% or greater of predicted
FEV1, FEV1 was marginally lower in ID genotype
carriers than DD genotype carriers (weighted mean difference −3.50,
P=0.056).Conclusions:Our meta-analytical findings demonstrated that the ACE gene
I/D polymorphism was not associated with the risk of chronic obstructive
pulmonary disease.