Healthful dietary patterns and long-term weight change among women with a history of gestational diabetes mellitus

BACKGROUND/OBJECTIVE: Diet represents a key strategy for the prevention of obesity and type 2 diabetes among women with a history of gestational diabetes mellitus (GDM), although effective dietary patterns to prevent weight gain in the long-term are largely unknown. We sought to evaluate whether improvement in overall diet quality is associated with less long-term weight gain among high risk women with prior GDM. SUBJECTS/METHODS: Women with a history of GDM (N=3 397) were followed from 1991 to 2011, or until diagnosis of type 2 diabetes or other chronic disease. Usual diet was assessed via food frequency questionnaire every 4 years from which we calculated the Alternative Healthy Eating Index (aHEI-2010), Alternate Mediterranean Diet (AMED), and Dietary Approaches to Stop Hypertension (DASH) dietary pattern scores. Weight, lifestyle, and health-related outcomes were self-reported every 2 years. We estimated the change in dietary score with change in body weight using linear regression models adjusting for age, baseline body-mass index, baseline and simultaneous change in physical activity and smoking status, and other risk factors. RESULTS: Women were followed up to 20 years, gaining an average 1.9 kg (SD=7.0) per 4-year period. Women in the highest quintile (Q5) of diet change (most improvement in quality) gained significantly less weight per 4-year period than the lowest quintile (Q1; decrease in quality), independent of other risk factors (4-year weight change, aHEI-2010: Q5=1.30 kg vs. Q1=3.27 kg; AMED: Q5=0.94 kg vs. Q1=2.56 kg, DASH: Q5=0.64 kg vs. Q1=2.75 kg). Significant effect modification by BMI (p-interactions <0.001) indicated a greater magnitude of weight change among women with a higher baseline BMI for all three patterns. CONCLUSIONS: Increased diet quality was associated with less weight gain, independent of other lifestyle factors. Postpartum recommendations on diet quality may provide one strategy to prevent long-term weight gain in this high risk group.