Predictors of insulin resistance in the obese with metabolic syndrome

BackgroundIn the obese, the metabolic syndrome (MetS) is assumed to reflect insulin resistance.ObjectiveTo determine the predictors of insulin resistance in obese subjects with MetS.DesignWe used the 90th percentile of the homeostasis model assessment (HOMA) to define insulin resistance in 4958 nondiabetic adults evaluated in the National Health and Nutrition Examination Surveys, 1999–2004, and compared the 373 obese subjects who were insulin-resistant (HOMA 9.52 ± 5.73) to a control group of 373 obese who had the highest sensitivity to insulin (HOMA 1.79 ± 0.44).MeasurementsMetS was present in 312 (83.6%) obese with insulin resistance and in 156 (41.8%) obese from the insulin-sensitive control group. Demographic, metabolic, and lifestyle variables were analyzed with logistic regression.ResultsIn a logistic model of insulin resistance given the presence of MetS, the significant predictors were triglycerides (P = 0.0021), body mass index (P = 0.0096), HDL-cholesterol (P = 0.0098), age (P = 0.0242) and smoking (P = 0.0366).LimitationsCross-sectional design prevents elucidation of causality for the association between insulin resistance and MetS.ConclusionsInsulin resistance is not an obligatory correlate of MetS in the obese. Its likelihood can be predicted by cigarette smoking and by the severity of obesity and dyslipidemia.