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 (SI) (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 SI 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.