Maternal age and the risk of gestational diabetes mellitus: A systematic review and meta-analysis of over 120 million participants.

The objective of the present analysis was to evaluate and quantify the risk for gestational diabetes mellitus (GDM) according to maternal age.Three electronic databases were searched for publications from inception to July 2018. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated. A dose-response analsis was performed using generalised least squares regression. Subgroup and meta-regression analyses were conducted to explore the source of identified heterogeneity among studies.Twenty-four studies were included in the present meta-analysis. The ORs and 95% CIs for women aged <20 years vs 25-29 years, 30-34 years, 35-39 years and ≥40 years were 0.60 (95% CI = 0.50-0.72), 1.69 (95% CI = 1.49-1.93), 2.73 (95% CI = 2.28-3.27), 3.54 (95% CI = 2.88-4.34) and 4.86 (95% CI = 3.78-6.24), respectively. Dose-response analysis showed that GDM risk exhibited a linear relationship with maternal age (P < 0.001). For each one-year increase in maternal age from 18 years, GDM risk for the overall population, Asian, and Europid increased by 7.90%, 12.74%, and 6.52%, respectively. Subgroup analyses indicated that from the age of 25, Asian women had a significantly higher risk of developing GDM than Europid women (all P < 0.001).This meta-analysis demonstrates that the risk of GDM increases linearly with successive age-groups.