233 Nutr Metab Cardiovasc Dis (2004) 14:233-240 ORIGINAL ARTICLE Alcohol intake and insulin resistance. A cross-sectional study R. Villegas, A. Salim, D. O'Halloran, and I.J. Perry A bstract Background and Aim: The development of insulin resis- tance is a critical step in the pathogenesis of type 2 diabetes. The effect of alcohol intake on insulin sensitivity~resistance is not well defined. The aim of this study was to examine the association between alcohol intake and insulin resistance in a sample of middle-aged men and women with data on a wide range of potential confounding factors, including diet. Methods: We performed a cross sectional study involving a group of 1018 men and women, sampled from 17 general practice lists in the South of Ireland, with a response rate of 69%. Participants completed a detailed health and lifestyle questionnaire and a food frequency questionnaire and pro- vided fasting blood samples for analysis of glucose and insulin. Insulin resistance was estimated on the basis of fast- ing glucose and insulin, using the glucose homeostasis model (HOMA scores). Insulin resistance was defined as the upper quartile of the HOMA scores. Results: We found evidence of a U-shaped relationship between alcohol intake and insulin resistance fitted as a con- tinuous variable (HOMA scores) with lowest levels in light drinkers (between 0.5 to 0.99 units per day) relative to the other drinking categories. However no significant association between alcohol intake and HOMA score was observed in fully adjusted analyses, including adjustment for dietary satu- rated fat and fruit and vegetables intake. In logistic regression analysis with insulin resistance (categorical) as the dependent variable, we observed that ex-drinkers were at higher risk of Key words: Insulin resistance, alcohol, middle age men and women. Correspondence to: Prof, I.J. Perry, Department of Epidemiology and Public Health, Distillery House, North Mall, University College Cork, Cork, Ireland Email: i.perry@ucc.ie Received: 30 September 2003; accepted: 26 February 2004 insulin resistance compared to occasional drinkers indepen- dently of age, sex, BMI and waist circumference, (0R=2.4, 95%CI, 1.1-5.7, p=O.04). On further adjustment for potential confounders including diet this association was also attenuat- ed and was non-significant. Conclusions: The reported effects of alcohol intake on insulin resistance may be confounded by other aspects of lifestyle, especially diet. Nutr Metab Cardiovasc Dis (2004) 14:233-240 ~2004, Medikal Press Introduction Alcohol is a widespread and potentially important risk factor for chronic disease. It is now accepted that there is a U-shaped association between alcohol intake and cardio- vascular disease, with lowest risk in light to moderate drinkers relative to both non-drinkers and heavy drinkers, (1). However, the association between alcohol intake and type 2 diabetes is less well defined with studies reporting positive (2, 3), inverse (4-6) and non-linear (U shape) asso- ciations (7-9). A number of studies have reported that light to moderate alcohol intake may increase insulin sensitivity (10-15). However, the potential confounding role of diet has only been addressed in some of the studies, (12, 14, 15). There is evidence that diet varies with alcohol intake and diet is an important risk factor for insulin resistance and type 2 dia- betes (16). Thus it is important to quantify the independent association between alcohol consumption and insulin resis- tance adjusted for other lifestyle factors, including diet. We have examined associations between alcohol intake and insulin resistance adjusted for a wide range of potential confounding factors, including diet in a general population sample of middle-aged men and women.