The estimation model for appendicular skeletal muscle mass in US children and adolescents

Background Adult guidelines recommend height-adjusted appendicular skeletal muscle mass (ASM) as the evaluation index for muscle mass.Aim To develop and validate predictive equations for ASM in children and adolescents.Subjects and methods A cross-sectional secondary analysis of National Health and Nutritional Examination Surveys (NHANES) data was conducted on United States children and adolescents aged 8–19 years. ASM was assessed by the sum of the lean mass of the upper and lower limbs. Multiple linear regression analyses were performed to estimate ASM using age, race and anthropometric variables [standing height (Ht), weight (Wt), arm circumference (AC) and waist circumference (WC)] with different combinations.Results Using multiple linear regression analyses, two predictive equations were generated. Equation = 0.502 + 0.388 * Wt (kg) − 0.234 * WC (cm) + 0.217 * Age (y) + 1.055 * Race (non-black = 0, black = 1) + 0.066 * Ht (cm) was for boys (adjusted R2 0.965 and standard error of the estimate (SEE) 1.42 kg). Equation = −2.868 + 0.261 * Wt (kg) − 0.092 * WC (cm) + 1.357 * Race (non-black = 0, black = 1) + 0.066 * Ht (cm) was for girls (adjusted R2 0.938 and SEE 1.18 kg).Conclusion The two anthropometric prediction equations presented for ASM are simple and accurate tools for predicting ASM in US children and adolescents.