Relationship Between Moderate Alcohol Consumption and Adiponectin and Insulin Sensitivity in a Large Heterogeneous Population

In the January issue of Diabetes Care, Sierksma et al. (1) reported that moderate alcohol consumption increased adiponectin serum levels and improved insulin sensitivity in a small group of insulin-resistant middle-aged men using a longitudinal study. This finding prompted us to examine the effect of moderate alcohol consumption on these parameters in our large heterogeneous group of nondiabetic subjects with and without family history of type 2 diabetes (2,3). Subjects with clinically suspected alcohol abuse were excluded from the study. Data on alcohol consumption (derived from a simple questionnaire) and insulin sensitivity (estimated from the oral glucose tolerance test using a validated index [4]) were available in 852 subjects (299 men and 586 women) and serum adiponectin concentrations in 752 subjects. Alcohol consumption categories were defined as follows: Alc 0 = no alcohol consumption (n = 145), Alc 1 = alcohol consumed only occasionally (n = 363), Alc 2 = alcohol consumed 2–3 days a week (including at weekends only) (n = 296), Alc 3 = alcohol consumed on >5 days a week (n = 48).

In Alc 0, insulin sensitivity was significantly lower (18.0 ± 1.0) compared with subjects in category 1 (18.6 ± 0.6), category 2 (21.1 ± 0.6), and category 3 (21.4 ± 1.7) (P = 0.04 after adjusting for sex, age, and percentage body fat). Because of sex differences in alcohol metabolism (5) and adiponectin serum levels (3), the relationship between alcohol consumption on adiponectin was analyzed separately in men and women. Adiponectin serum levels were higher in men consuming alcohol on 2 or more days a week (Alc 2 + 3) (9.2 ± 0.3 μg/ml) compared with men consuming no or occasional alcohol (Alc 0 + 1) (8.4 ± 0.3 μg/ml, P = 0.05 after adjusting for percentage body fat). Abstinent women (Alc 0) were found to have significantly lower adiponectin serum concentrations (11.7 ± 0.5 μg/ml) than women consuming alcohol (Alc 1 − 3) (13.3 ± 0.3 μg/ml, P = 0.03 after adjusting for percentage body fat).

In summary, our findings support the notion that moderate alcohol consumption has positive effects on insulin sensitivity and adiponectin serum levels. These effects are not only present in the small homogenous group studied by Sierksma et al. (1), but can also be demonstrated in a large and more heterogeneous group of healthy subjects. In women, the alcohol effects seem to be demonstrable at lower doses than in men.