A cross-sectional study of alcohol consumption patterns and biologic markers of glycemic control among 459 women

OBJECTIVE - Little research has explored associations of drinking patterns with glycemic control, especially among women. Our objective was to determine the relationship of patterns of alcohol consumption-including average daily consumption, weekly frequency of consumption, drinking with meals, and beverage type-with biologic markers of insulin resistance in young women. RESEARCH DESIGN AND METHODS - This study was cross-sectional in design. The subjects consisted of a stratified random subpopulation of 459 U.S. normal-weight and overweight female nurses, 33-50 years of age, drawn from the Nurses' Health Study II and sampled for distinct drinking patterns. Women provided blood samples and detailed information on dietary and lifestyle factors between 1995 and 1999. The main outcome measures were fasting insulin, C-peptide, and HbA1c. RESULTS - Adjusting for age, smoking, physical activity, television watching, BMI, and several dietary factors, average alcohol intake was inversely associated with HbA1c (units in percentage of HbA1c): 0 g/day (reference = 5.36%), 0.1 to <5.0 g/day (-0.04%), 5.0 to <15.0 g/day (-0.09%), 15.0 to <25.0 g/day (-0.10%), and ≥25.0 g/day (-0.17%) (P value, test for trend <0.001). We found an inverse association of alcohol intake and insulin, but only for women with a BMI ≥25 kg/m2. Specifically, insulin levels were lowest for episodic drinkers consuming ≥2 drinks per day on 0-3 days per week. Consumption with meals and type of alcoholic beverage did not further influence these results. CONCLUSIONS - Moderate alcohol consumption of 1-2 drinks per day on a few to several days of the week may have a beneficial glycemic effect, particularly among overweight women.