MECHANISMS IN ENDOCRINOLOGY: Parity and risk of type 2 diabetes: a systematic review and dose-response meta-analysis

Eur J Endocrinol. 2016 Nov;175(5):R231-45. doi: 10.1530/EJE-16-0321. Epub 2016 Jun 22.

Abstract

Objective: Epidemiologic studies regarding the association between parity and risk of type 2 diabetes have yielded inconsistent results. Therefore, we performed a systematic review and dose-response meta-analysis to determine the relation between parity and type 2 diabetes risk.

Methods: We searched PubMed and Embase for published epidemiologic studies that assessed the relation between parity and risk of type 2 diabetes up to 31 March 2016. A dose-response random-effects model was used to combine study-specific relative risks (RRs) and 95% confidence intervals (CIs). Potential sources of heterogeneity were explored by meta-regression and subgroup analyses.

Results: Seven cohort studies, 1 case-control study and 9 cross-sectional studies including 296 923 participants were eligible for inclusion. The combined RR for the highest versus lowest category of parity indicated a 54% increment in type 2 diabetes risk (95% CI: 29-83%). In the cubic spline model, a nonlinear association was found between parity and risk of type 2 diabetes (P = 0.02 for nonlinearity). Compared with nulliparous women, the estimated RR (95% CI) of type 2 diabetes for women with one to seven children was 1.01 (0.96-1.07), 1.08 (1.00-1.16), 1.20 (1.12-1.30), 1.32 (1.22-1.42), 1.37 (1.27-1.48), 1.39 (1.26-1.52) and 1.39 (1.23-1.57) respectively.

Conclusions: Higher parity is significantly associated with an increased risk of type 2 diabetes. Further studies are warranted to fully adjust for the potential confounders and explore the causality between parity and type 2 diabetes risk.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Diabetes Mellitus, Type 2 / etiology*
  • Female
  • Humans
  • Parity / physiology*
  • Pregnancy
  • Risk