High Calorie Intake Is Associated With Worsening Insulin Resistance and β-Cell Function in Hispanic Women After Gestational Diabetes Mellitus

OBJECTIVE: To assess associations between dietary intake and rates of change in insulin resistance and β-cell function in Hispanic women with prior gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: Sixty-two nondiabetic Hispanic women with pregnancies complicated by GDM completed oral and intravenous glucose tolerance tests and bioelectrical impedance measurements of body fat every 12–15 months postpartum for up to 12 years. Self-reported dietary intake was collected at all visits by structured food frequency questionnaires developed for Hispanics. Mixed-effects models were used to assess the relationship between dietary intake and rates of change in metabolic outcomes during follow-up. RESULTS: The median length of follow-up from the first postpartum evaluation was 8.0 years (interquartile range 4.5–10.8 years). At baseline, women were 32 ± 5.7 years old and had a median calorie intake of 2,091 kcal/day. Over the course of follow-up, dietary intake did not change significantly. Higher baseline calorie intake was associated with a faster decline in insulin sensitivity, measured by the insulin sensitivity index (S(I)) (P = 0.029), and β-cell compensation, measured by the disposition index (DI) (P = 0.027), over time. These associations remained after adjustment for baseline characteristics; changes in BMI, calorie intake, levels of physical activity; and additional pregnancies during the follow-up period. The median rates were −0.06 vs. −0.02 units/year for S(I) and −810 vs. −692 units/year for DI for women with baseline calorie intake above versus below the cohort median. CONCLUSIONS: High calorie intake is associated with a faster decline in insulin sensitivity and β-cell compensation in Hispanic women who are at high risk for type 2 diabetes, independent of adiposity.