1386-P: Long-Term Weight Change after Pregnancy and Type 2 Diabetes Risk in Women with a History of Gestational Diabetes

Women with a history of gestational diabetes (GDM) are at high risk for developing type 2 diabetes, which may be further increased with weight gain after pregnancy. Our objective was to determine associations of long-term weight changes after a GDM pregnancy and type 2 diabetes risk. We used data on a cohort of 139 women with a GDM pregnancy identified though the Kaiser Permanente Northern California (KPNC) GDM registry (1986-2009) who completed a follow-up study visit an average of 16 years later (2011-2013). Type 2 diabetes was identified through the KPNC diabetes registry, self-report during follow-up visit recruitment, or at least one abnormal value on a 75-gram, 2-hour oral glucose tolerance test (2015 ADA criteria) conducted at the follow-up visit. Clinically measured weights extracted from the electronic health record were used to calculate average BMI change per year between delivery and either type 2 diabetes identification date or follow-up visit date. We used modified Poisson regression to estimate relative risks of type 2 diabetes associated with BMI change categories. Twenty-six percent of women lost weight [mean -0.3 BMI units/year, equivalent to -0.8 kg/year for a woman of the average height in our cohort (1.6 m)], 24% maintained their weight (<0.17 BMI units/year, mean 0.10 BMI units/year [0.3 kg/year]), and 50% gained weight (≥0.17 BMI units/year, mean 0.5 BMI units/year [1.3 kg/year]). Overall, 50% of women developed type 2 diabetes. Each additional BMI unit gained was associated with 28% greater risk of type 2 diabetes (95% CI: 0.98, 1.67) adjusting for age at delivery, race/ethnicity, pre-pregnancy BMI, and years since delivery. Women who lost weight had 39% lower risk of developing type 2 diabetes (95% CI: 0.33, 1.12) compared to women who maintained their weight, though estimates were imprecise. Our findings suggest that long-term weight gain after a GDM pregnancy may increase risk of type 2 diabetes, supporting postpartum weight loss intervention efforts.