Higher parity is associated with increased risk of Type 2 diabetes mellitus in women: A linear dose–response meta-analysis of cohort studies

Abstract

AimThe goal of this study is to investigate the association between higher parity and the risk of occurrence of type 2 diabetes mellitus (T2DM) in women and to quantify the potential dose–response relation. MethodsWe searched MEDLINE, and EMBASE electronic databases for related cohort studies up to March 10th, 2016. Summary rate ratios (RRs) and 95% confidence intervals (CIs) for T2DM with at least 3 categories of exposure were eligible. A random-effects dose–response analysis procedure was used to study the relations between them. ResultsAfter screening a total of 13,647 published studies, only 7 cohort studies (9,394 incident cases and 286,840 female participants) were found to be eligible for this meta-analysis. In the category analysis, the pooled RR for the highest number of parity vs. the lowest one was 1.42 (95% CI: 1.17–1.72, I2=71.5%, Pheterogeneity=0.002, Power=0.99). In the dose–response analysis, a noticeable linear dose–risk relation was found between parity and T2DM (Pfor nonlinearity test=0.942). For every live birth increase in parity, the combined RR was 1.06 (95% CI: 1.02–1.09, I2=84.3%, Pheterogeneity=0.003, Power=0.99). Subgroup and sensitivity analyses yielded similar results. No publication bias was found in the results. ConclusionThis meta-analysis suggests that higher parity and the risk of T2DM show a linear relationship in women.