Association Between Vitamin D and Muscle Mass and Function in Children and Adolescents

OBJECTIVE: This study aimed to investigate the association between vitamin D and muscle health in children and adolescents. DESIGN: A cross-sectional analysis was performed using data from 2,775 participants aged 8-17 years in NHANES 2011-2014. Muscle mass was evaluated through whole-body and regional muscle-to-fat ratios (MFRs), while muscle function was assessed using relative handgrip strength (RHGS). Vitamin D status was characterized by serum 25-hydroxyvitamin D (25(OH)D), 25(OH)D3, 25(OH)D2 levels, and 25(OH)D categorized as deficient, insufficient, or sufficient. The analysis employed covariate-adjusted linear regression and restricted cubic splines (RCS), with predictive ability of RHGS assessed via receiver operating characteristic (ROC) analysis. RESULTS: Significant positive associations between total 25(OH)D levels and muscle-related parameters were observed across adjusted models. Associations varied across sex and age groups, and RHGS demonstrated limited predictive value for vitamin D status across all subgroups (maximum AUC = 0.635). CONCLUSIONS: Total 25(OH)D appeared to be the most informative indicator of vitamin D status in relation to pediatric muscle health, although associations varied to sex, age, and assessment measures. RHGS demonstrated limited utility as a screening indicator for vitamin D insufficiency or deficiency status.