Association between lean mass, fat mass, and waist circumference with bone mineral density in Mexican children and adolescents: a cross-sectional study.

To assess the associations of lean mass (LM), fat mass (FM), truncal fat mass (TFM), and waist circumference (WC) with bone mineral density (BMD) in Mexican youth, independently of body weight. We analyzed cross-sectional data from 1,054 children and adolescents from the Health Workers Cohort Study. We measured total and region-specific BMD, LM, and FM, with dual-energy X-ray absorptiometry. To eliminate the effect of body weight on FM, LM, TFM, and WC, weight-adjusted values were generated using the residuals method, and then we employed multivariate linear regression models adjusted for relevant potential confounders. We further stratified the analysis by sex, age group, and sexual maturation. LM was positively associated with BMD in various anatomical sites, with β coefficients ranging from 0.004 to 0.013 in both sexes (P < 0.05). FM was inversely related to total BMD and other sites, with β coefficients ranging from -0.013 to -0.006 (P < 0.05). WC showed negative associations with BMD at some sites, with β values ranging from -0.007 to -0.002. TFM was negatively associated with BMD. During puberty, the associations were consistent across all sites, whereas this was not the case for all sites after puberty. These patterns were similarly observed across different age groups.Conclusion: An increased LM and reduced FM are associated with higher BMD, particularly in the leg and hip regions, during childhood and adolescence, a critical developmental stage essential for healthy bone accrual and balance in adulthood.