ASSOCIATION OF DIETARY-COMPOSITION WITH FASTING SERUM-INSULIN LEVEL -THE ARIC STUDY

Insulin resistance and subsequent hyperinsulinemia are risk markers fo r diabetes and have been implicated in the development of cardiovascul ar disease; therefore, modifiable determinants of the serum insulin le vel are of interest. Several studies have suggested that certain dieta ry components, particularly fat and alcohol, may be associated with bo th fasting and postprandial insulin concentrations independent of obes ity. The relation of dietary intake, assessed by a modified version of the Willett 61-item food frequency questionnaire, to fasting serum in sulin was examined in 13,167 nondiabetic men and women, aged 45-64. Un ivariately, fasting insulin was associated positively (p<0.01) with en ergy intake. After adjustment for gender, race, age, energy intake, bo dy mass index, waist-to-hip ratio, smoking, and physical activity in m ultivariate models, alcohol was negatively associated with insulin, wi th the predicted difference in insulin for the interquartile range bei ng 5.0% (95% CI = 6.3%-3.6%). A significant inverse association was al so observed between dietary fiber and insulin among women, but not men . Total fat, saturated fat, monounsaturated fat, and carbohydrates wer e associated positively (P<0.05) with fasting insulin, but the magnitu de of these associations was small. The predicted percent difference i n insulin for persons at the 25th versus the 75th percentile of total fat, saturated fat, monounsaturated fat, and carbohydrates was 2.3%, 2 .3%, 2.2%, and 1.4%, respectively. These data suggest that dietary com position may have modest effects on fasting insulin level, beyond the contributions of energy imbalance and obesity.