Fat mass accumulation compromises bone adaptation to load in finnish women: A cross-sectional study spanning three generations

Abstract

Body weight and lean mass correlate with bone mass, but the relationship between fat mass and bone remains elusive. The study population consisted of 396 girls and 138 premenopausal mothers and 114 postmenopausal grandmothers of these girls. Body composition and tibial length were assessed using dual-energy X-ray absorptiometry (DXA), and bone traits were determined at the tibia using peripheral quantitative computed tomography (pQCT) in the girls at the ages of 11.2±0.8, 13.2±0.9, and 18.3±1.0 years and in the mothers (44.7±4.1 years) and grandmothers (70.7±6.3 years). The values of relative bone strength index (RBSI), an index reflecting the ratio of bone strength to the load applied on the tibia, were correlated among family members (all p .05), indicating that the bone-strength deficit was attributable to increased fat mass, not lean mass. Moreover, the adverse effect of fat mass was age-dependent, with every unit increase in fat mass associated with a greater decrease in RBSI in pre- and postmenopausal women than in girls (all p