The Association Between Total and Regional Body Fat and Bone Mineral Content in Young Athletes: A Cross-Sectional Study

Background: Excess body fat during growth has been associated with impaired bone development; however, evidence on the influence of total and regional body fat on bone mineral content (BMC) in physically active youth remains limited. Objective: This study aimed to analyze the association between total and regional body fat and BMC in children and adolescent athletes. Methods: This cross-sectional study included 109 children and adolescents aged 9 to 18 years participating in different sports (indoor volleyball, beach volleyball, swimming, track and field, and basketball). Bone mineral content assessed by DXA and normalized by height (BMC/Height) for the total body less head (TBLH), lumbar spine (L1–L4), and femoral neck was considered the dependent variable. Total and regional (android and gynoid) body fat percentages obtained by dual-energy X-ray absorptiometry (DXA) were treated as independent variables. Associations were examined using multivariable linear regression adjusted for biological and training-related covariates. Results: Total body fat (β = −0.014; p < 0.05), android fat (β = −0.011; p < 0.05), and gynoid fat (β = −0.014; p < 0.05) were significantly and inversely associated with lumbar spine BMC/Height. No associations were observed between total, android, or gynoid fat percentage and TBLH or femoral neck BMC/Height (p > 0.05). Conclusions: The inverse and site-specific association of total, android, and gynoid fat with lumbar spine BMC/Height highlights the greater susceptibility of this skeletal site to adiposity-related detriments, underscoring the importance of site-specific monitoring of bone mineral content, even among physically active youth.