Association of muscular strength with total and central adiposity in adolescents with intellectual disability

It has been established that for youth without disabilities, muscular strength (MS) is negatively associated with total and central adiposity. However, this relationship has not been clearly established for youth with intellectual disability (ID). The purpose of this study was to examine the association of MS with total and central adiposity in adolescents with ID.

Participants were 59 adolescents (40 males and 19 females: age 16.29 ± 1.66 years) with ID. Total and central adiposity were evaluated with dual-energy x-ray absorptiometry (DXA), body mass index (BMI), BMI z-score, waist circumference (WC), and conicity index (C-index). MS was evaluated with the score on the Bruininks-Oseretsky Test of Motor Proficiency (range, 0 to 42, with higher scores indicating better performance). Sex-specific maturity offset equations were used to evaluate somatic maturity. Spearman's correlation coefficients and sequential multiple regression were used to examine associations between MS and adiposity.

Muscular strength score was negatively associated with BMI (sr = -0.32; P < 0.05), percent body fat (%BF; total, trunk, android and gynoid regions) (sr = -0.51 to -0.58; P < 0.01), and android-to-gynoid fat ratio (sr = -0.29; P < 0.05). After control for somatic maturity and sex, regression analysis indicated that MS score explained 10%-17% of the variance in BMI, BMI z-score, %BF (total, trunk, android and gynoid regions), WC, C-index and android-to-gynoid fat ratio.

These findings suggest that MS is associated with DXA- and anthropometric-determined total and central adiposity among adolescents with ID.