Association of muscle mass and fat mass on low- density-lipoprotein cholesterol and triglyceride plasma concentration in children and adolescents

Objectives: Obesity has often been associated with high low-density-lipoprotein cholesterol (LDL-C) and triglycer-ide plasma concentrations, known risk factors for diabetes mellitus and cardiovascular disease. Study objective was to evaluate the association of LDL-C and triglyceride plasma concentration with muscle and fat mass in children and adolescents. Methods: We analyzed data of the National Health and Nutrition Examination Survey (1999-2004) to estimate lean muscle and fat mass assessed by dual-energy X-ray absorptiometry (DXA) of participants whose lipid profiles had been examined. Fat mass was operationalized by DXA-determined fat mass index (FMI). Muscle mass was assessed by appendicular lean mass index (aLMI). High LDL-C and triglyceride concentration was defined as above 130 mg/dL. Results: For the evaluation of the association of LDL-C and triglyceride plasma concentration with LMI and FMI Z-scores, the data of 2,487 children and adolescents (age 8-19 years) (984 females) were eligible. High aLMI showed no association with LDL-C or triglyceride concentration, but high FMI showed significant association with LDL-C and triglyceride plasma concentration in the bivariate regression analysis. Conclusions: Isolated muscle mass increase may not be protective against high LDL-C and triglycerides plasma levels in children and adolescents. Thus, exercise may lead to risk factor reduction mainly through fat mass reduction.