Interaction Between Maternal Obesity and Gestational Diabetes Mellitus and Long-Term Development of Diabetes, Hypertension and Cardiovascular Disease: A Population-Level Analysis

To examine how maternal obesity modulates the long-term risk of developing diabetic and vascular complications among women with and without GDM. We linked data from a population-level clinical registry (the Alberta Perinatal Health Program) for 253 970 deliveries between April 1999 and March 2010 with administrative health claims. Women were grouped as: 1) no GDM, not obese (n=225 145, reference group); 2) obese only (n=19 051); 3) GDM only (n=8135); and 4) GDM and obese (n=1639). Maternal obesity was defined as pre-pregnancy weight >91 kg. During a median follow-up of 4.7 years, diabetes incidence was 35.1% in the GDM and obese, 18.5% in the GDM only, 5.2% in the obese only, and 1.2% in the reference groups, respectively (Figure, left panel, p<0.01). With respect to hypertension and cardiovascular disease, women with GDM who were obese had the highest rates (25.8% and 3.2%, respectively) and the reference group had the lowest rates (5.6% and 0.8%, respectively). However, the rates were similar among women with GDM only (15.6% and 1.2%, respectively) and women who were obese only (15.2% and 1.3%, respectively – Figure, middle and right panel). These findings remained after multivariable adjustment for baseline differences. The presence of both obesity and GDM compounds the risk of developing diabetes. However, the association between obesity alone and GDM alone and hypertension and cardiovascular disease appears equivalent suggesting a need for interventions that target effective management of both these factors to improve the health of this patient population.