Total body bone mineral content and tibial cortical bone measures in preschool children

This study was undertaken to identify factors that influence total body bon e area (TBBA), total body bone mineral content (TBBMC), and tibial cortical bone measures in 239 children aged 3-5 years. We obtained information on d emographic and anthropometric characteristics and measurements of diet, phy sical activity, and strength. In multiple regression analysis, TBBA correla ted with height (p < 0.001), weight (p < 0.001), percent body fat (p < 0.00 1), and calcium intake (p = 0.02). TBBMC correlated with TBBA (p < 0.001), age (p = 0.001), and weight (p = 0.02) and inversely correlated with height (p < 0.001) and percent body fat (p < 0.001). Children born preterm had lo wer TBBMC compared with children born at term (p = 0.02). Both periosteal a nd endosteal circumferences were correlated with weight (both,p < 0.001) an d inversely correlated with age (p = 0.006 and p = 0.003, respectively) and percent body fat (p = 0.002 and p = 0.005 respectively). Endosteal circumf erence was greater and cortical bone area was lower in children born preter m compared with those born at term (both, p = 0.04). Findings of higher TBB A and lower TBBMC in children with high percent body fat indicate undermine ralization of bone and suggest that obesity in preschool children may have detrimental effects on total body bone mass accretion. A smaller tibial per iosteal circumference and thus cross-sectional area in children with the sa me weight but higher percent body fat also would lead to a biomechanical di sadvantage in these children. Findings of low TBBMC and cortical bone area among children born preterm need to be confirmed in other populations. We s peculate that differences in these measurements between children born prete rm and at term may be caused by differences in activity.