Insulin secretion, obesity, and potential behavioral influences: results from the Insulin Resistance Atherosclerosis Study (IRAS)

Abstract

Background This work was conducted to evaluate associations of insulin secretion with overall and central obesity, dietary fats, physical activity, and alcohol. Methods A frequently sampled intravenous glucose tolerance test (FSIGT) was used to assess acute insulin response to glucose (AIR) and insulin sensitivity (S_I) among adult participants (n=675 with normal, NGT; n=332 with impaired glucose tolerance, IGT) in the Insulin Resistance Atherosclerosis Study (IRAS). Disposition index (DI) was calculated as the sum of the log-transformed AIR and S_I to reflect pancreatic compensation for insulin resistance. Obesity was measured as body mass index (kg/m², BMI) and central fat distribution by waist circumference (cm). Dietary fat intake (total, saturated, polyunsaturated, oleic acid), physical activity, and alcohol intake were assessed by standardized interview. Results In unadjusted analyses, BMI and waist were each positively correlated with AIR among NGTs (r=0.26 and 0.23, respectively; pr=0.10, NS; r=0.13, pr=−0.13 and −0.20, respectively; pr=−0.20 and −0.19, respectively, pppp<0.01). None of the behavioral variables were independently related to either outcome. Conclusion Among non-diabetic patients, central obesity appears to be related to higher insulin secretion, but to lower capacity of the pancreas to respond to the ambient insulin resistance. Copyright © 2001 John Wiley & Sons, Ltd.