Association of Habitual Alcohol Consumption With Long-term Risk of Type 2 Diabetes Among Women With a History of Gestational Diabetes

Importance: Women with gestational diabetes are at high risk for type 2 diabetes. Identifying modifiable dietary and lifestyle factors, such as alcohol intake, that can be useful in delaying or preventing progression to overt type 2 diabetes is of particular interest. Objective: To evaluate the association between alcohol consumption and risk for type 2 diabetes among women with a history of gestational diabetes. Design, Setting, and Participants: This cohort study included women from the Nurses' Health Study II cohort who reported a history of gestational diabetes and were followed up from January 1, 1991, to December 31, 2017, as part of the Diabetes the mean (SD) age at baseline was 38.2 (5.0) years, and the median follow-up time was 24 years (interquartile range, 18-28 years), resulting in 78 328 person-years of follow-up. During this period, 897 incident cases of type 2 diabetes were reported. After adjustment for major dietary and lifestyle factors, compared with women who did not consume any alcohol, only alcohol consumption of 5.0 to 14.9 g/d was associated with decreased risk for incident type 2 diabetes (HR, 0.45; 95% CI, 0.33-0.61); there was no association of alcohol consumption of 0.1 to 4.9 g/d or 15.0 g/d or more (maximum, 74.2 g/d) with risk of type 2 diabetes (0.1 to 4.9 g/d: HR, 0.87 95% CI, 0.73-1.03; ≥15.0 g/d: HR, 0.62 95% CI, 0.37-1.04). After additional adjustment for body mass index, women who reported alcohol consumption of 5.0 to 14.9 g/d had a 41% lower risk for developing incident type 2 diabetes (HR, 0.59; 95% CI, 0.42-0.81); consumption of 0.1 to 4.9 g/d and consumption of 15.0 g/d or more were still not associated with risk of type 2 diabetes, but the results were attenuated (0.1-4.9 g/d: HR, 1.02 95% CI, 0.85-1.23; ≥15.0 g/d: HR, 0.75 95% CI, 0.42-1.33). Conclusions and Relevance: In this cohort study, among women with a history of gestational diabetes, usual alcohol intake of 5.0 to 14.9 g/d (approximately 0.5-1 drinks per day) was associated with a lower risk for type 2 diabetes. These findings should be interpreted in the context of other known risks and benefits of alcohol consumption when considering clinical recommendations for individual women with a history of gestational diabetes.