Lean insulin-resistant young adults display increased cardiometabolic risk: A retrospective cross-sectional study

Aim: We investigated whether lean insulin-resistant individuals manifest increased cardiometabolic risk. Methods: 2,341 (51.8% females) healthy 16-23-year-old subjects were categorized as lean or overweight/obese; and insulin-sensitive or insulin-resistant, and compared. Results: In both sexes, lean insulin-sensitive and insulin-resistant subjects displayed similar measures of obesity (e.g., males, waist-to-height ratio: lean insulin-sensitive: 0.42 +/- 0.03, lean insulin-resistant: 0.43 +/- 0.03, overweight/obese insulin-sensitive: 0.49 +/- 0.05, overweight/obese insulin-resistant: 0.53 +/- 0.06). Lean insulinsensitive individuals were more insulin-sensitive compared with their overweight/obese peers; insulinresistant groups presented similar insulin-sensitivity (males, the Quantitative insulin-sensitivity check index (QUICKI): lean insulin-sensitive: 0.354 +/- 0.022, lean insulin-resistant: 0.304 +/- 0.013, overweight/obese insulinsensitive: 0.343 +/- 0.019, overweight/obese insulin-resistant: 0.299 +/- 0.015). The two-factor analysis of variance indicated an independent effect of insulin sensitivity, overweight/obesity, and their interaction on the continuous metabolic syndrome score (p < 0.001, all; males, lean insulin-sensitive: 1.87 +/- 0.35, lean insulin-resistant: 2.14 +/- 0.42, overweight/obese insulin-sensitive: 2.15 +/- 0.40, overweight/obese insulin-resistant: 2.75 +/- 0.69). C-reactive protein, leukocyte count, and glomerular filtration rate in both sexes; uric acid, asymmetric dimethylarginine, and soluble vascular adhesion protein-1 in males; and soluble receptor for advanced glycation endproducts in females were independently associated with insulin resistance. Among phenotypes associated with low QUICKI, the distribution of insulin-resistant individuals was random. Conclusion: Later clinical consequences of insulin resistance in lean subjects remain to be elucidated in longitudinal studies.