Obesity, insulin resistance, and the risk of an elevated alanine aminotransferase activity in the Korean adolescent population.

Background: It is unclear to what extent insulin resistance (IR) modulates the association linking obesity to alanine aminotransferase (ALT) activity elevation. Methods: We measured the homeostatic model assessment for IR (HOMA-IR) in 1591 participants aged 12-18 years from the 2008 to 2009 Korea National Health and Nutrition Examination Survey. Results: Overweight adolescents had an odds ratio of 7.23 [95% confidence interval (95% CI), 4.33-12.10] for an elevated ALT activity compared with normal-weight adolescents, and the corresponding risk was 23.62 (95% CI, 12.98-42.98) in obese adolescents. Adjustments for other participant factors did not substantially affect the results. The addition of the HOMA-IR data decreased the estimate for overweight adolescents by 27% and for obese adolescents, the decrease was 47%. Both obesity and IR markers remained independent predictors of outcome. Conclusions: The greater the obesity level, the more that IR contributes to the association between obesity and an elevated ALT activity.