Insulin resistance and metabolic syndrome criteria in lean, normoglycemic college-age subjects.

AIMS: The goal of this study was to determine insulin sensitivity in a fasted state and during an oral glucose tolerance test (OGTT), in normoglycemic (NGT), lean (L) (n = 35) and, for comparison, overweight/obese (OW/O) (n = 9) college-aged subjects. MATERIALS AND METHODS: Insulin sensitivity for 44 NGT, normotensive subjects, age 18-26 yrs., was determined by homeostasis model assessment (HOMA-IR) and from Matsuda index (ISI Matsuda). RESULTS: Subjects were normoglycemic fasted (4.59 + 0.35 mmol/L) and at two hours post OGTT (4.52  + 1.35 mmol/L). Besides anthropometric measures, there were significant differences between OW/O and L for fasting insulin (P < 0.001) and both measures of insulin sensitivity (P < 0.05). All subjects exhibited a 9-fold range in HOMA-IR (0.88 + 0.51, range 0.3-2.7) and an 8-fold range in ISI Matsuda (11.9 + 4.7, range 3.0-24.2). The latter was inversely correlated with systolic blood pressure (r = 0.35, P = 0.04) even though subjects were normotensive. In lean subjects, 2.3% were IR by HOMA-IR > 2.1, 5.7% by ISI Matsuda < 5.9, and 22.9% had >one criteria for metabolic syndrome (MetS); 28.6% had some negative metabolic biomarker. CONCLUSIONS: Insulin resistance is present in lean, NGT college-age subjects even without MetS criteria and is discernable with an easily applicable OGTT-derived index.