(PTFS13-04-26) Associations Between Adipose and Lean Soft Tissue Compartments and Bone Mineral Density Among Postmenopausal Women

Objectives: To investigate independent associations between total and regional body composition and total body (TB) and lumbar spine (LS) bone mineral density (BMD) among postmenopausal women.

Methods: This cross-sectional study used NHANES 2011-2018 data. Postmenopausal women were included and excluded if male, pregnant/breastfeeding, premenopausal/perimenopausal, missing DXA data, reporting implausible caloric intake ( < 500 or >5,000 kcal/day), using bone-modifying medications, or having severe renal impairment (eGFR < 30 mL/min/1.73 m²). Primary outcomes were TB and LS BMD measured by DXA. Survey-weighted linear regression examined associations between body composition predictors and BMD, adjusting for key covariates. A subgroup analysis was conducted for naturally menopausal women.

Results: The initial sample with available DXA data from NHANES 2011-2018 was 38,022. The analytic sample included 1,035 postmenopausal women (mean age 52.3 ± 0.2 years). Total lean mass was positively associated with TB BMD (β = 0.006, 95% CI: 0.004-0.008) and LS BMD (β = 0.007, 95% CI: 0.003-0.010). Total fat mass showed inverse associations with TB BMD (β = -0.003, 95% CI: -0.004 to -0.001) and LS BMD (β = -0.004, 95% CI: -0.006 to -0.001). Trunk lean mass was a significant regional predictor of TB BMD (β = 0.008, 95% CI: 0.004-0.012) and LS BMD (β = 0.008, 95% CI: 0.001-0.014). Visceral adipose tissue (VAT) was inversely associated with TB BMD (β = -0.056, 95% CI: -0.104 to -0.009) and LS BMD (β = -0.085, 95% CI: -0.152 to -0.018). In the natural menopause subgroup (n = 610), appendicular lean mass emerged as the primary predictor of TB BMD (β = 0.010, 95% CI: 0.003-0.017) and LS BMD (β = 0.012, 95% CI: 0.000-0.023), while trunk lean mass and VAT were no longer significant.

Conclusions: Lean mass and VAT are independently associated with BMD in postmenopausal women. The shift toward appendicular lean mass as the primary predictor in natural menopause suggests hormonal status may modify the skeletal response to mechanical loading. These findings highlight potential targets for resistance training and metabolic interventions to preserve bone health in this population.

Funding Sources: No external funding