Associations of education attainment with gestational diabetes mellitus and the mediating effects of obesity: A Mendelian randomization study

We aim to assess the causal association between educational attainment and gestational diabetes mellitus, and the mediating effect of obesity on this association. We estimated the causal effects of educational attainment on gestational diabetes mellitus using European ancestry genome-wide association study summary data with two-sample univariate Mendelian randomization (UVMR) approach. Two-stage Mendelian randomization analysis was performed to assess the potential mediating role of obesity traits in this association and to calculate the mediating proportion. UVMR analysis demonstrated that higher educational attainment was associated with a reduced risk of GDM (OR 0.76, 95% CI 0.67-0.86; p < 0.01). EA has also been associated with decreased obesity in women. Mediation Mendelian randomization results indicated that body mass index (BMI) was the most significant mediating factor in the relationship between educational attainment and GDM, accounting for 42.52% (95% CI 37.75-55.44%) of the effect, followed by waistto-hip ratio (WHR) at 34.35% (95% CI 29.82-46.41%), body fat percentage at 28.95% (95% CI 35.99-46.81%), and WHR adjusted for BMI (WHRadjBMI) at 12.51% (95% CI 36.2-58.5%). educational attainment exerts a potential causal protective effect against gestational diabetes mellitus, and obesity-related risk factors play a mediating role. Attention should be paid to the educational attainment of women, and obese women with lower educational attainment may represent a higher risk group for GDM than those with higher educational attainment.