Alcohol intake and fasting insulin in French men and women. The D.E.S.I.R. Study.

BACKGROUND To study the relation between alcohol consumption and the fasting insulin concentration in a French population with a range of alcohol intakes. METHODS 2.406 men and 2.500 women, aged 30 to 65 years who were not known as diabetic and with a non-diabetic fasting plasma glucose<7.0 mmol/l were studied. Insulin was assayed by a specific micro-enzyme immunoassay and alcohol intake was from a self-questionnaire. RESULTS Fasting insulin concentration showed an inverse linear association with alcohol consumption, after adjustment for age and possible confounding factors (p for trend<0.0001 men; p<0.002 women), with a 29% higher insulin in non-drinkers compared to very heavy drinkers (> 80 g/day) in men (p<0.0001) and a 23% and 26% difference when compared to heavy drinkers (41-80 g/day) in men and women respectively (p<0.0001, p<0.003). This relation did not differ significantly according to whether the alcohol was consumed as wine, beer/cider or spirits. Fasting plasma glucose modified the relation between alcohol and insulin in men: while the negative relation alcohol-insulin was strong for fasting plasma glucose<6.0 mmol/l (p<0.0001), there was no association above 6.0 mmol/l (p=0.4). CONCLUSION There is an inverse relation between alcohol consumption and fasting insulin concentrations. Some studies have found a U shaped relation, and this is probably due to the inclusion of diabetic subjects. As hyperinsulinemia has been shown to be positively associated with cardiovascular disease, it may be one of the variables that explains the protective effect of moderate alcohol consumption on cardiovascular disease.