Peak Bone Mass and Patterns of Change in Total Bone Mineral Density and Bone Mineral Contents From Childhood Into Young Adulthood.

The literature has not reached a consensus on the age when peak bone mass is achieved. This study examines growth patterns of total bone mineral content (TBMC) and total bone mineral density (TBMD), peak bone mass, effect of concurrent anthropometry measures, and physical activity on growth patterns in a sample of 312 white males and 343 females aged 8-30 yr. We analyzed data from participants enrolled in Fels Longitudinal Study. Descriptive analysis was used to ascertain characteristics of participants and growth patterns of TBMC and TBMD. Mixed effects models were applied to predict ages at attainment of peak TBMC and TBMD and assess the effects of height, weight, body mass index (BMI), and habitual physical activity on the attainment. Significant differences between sexes were observed for measures of TBMC and TBMD, and differences varied with age. For females, predicted median ages at peak TBMC and TBMD attainments are 21.96 yr (interquartile range [IQR]: 21.81-22.21) and 22.31 yr (IQR: 21.95-22.59), respectively. For males, predicted median ages are 23.34 yr (IQR: 24.34-26.19) and 26.86 yr (IQR: 25.14-27.98) respectively. For females, height, weight, and BMI, but not physical activity, had significant influences on attainment of TBMC and TBMD (p<0.01). For males, weight and BMI, but not height and physical activity, exerted significant influence on attainment of TBMC and TBMD (p<0.01), and also modified correlations between age and peak TBMC and TBMD. Our results suggest that (1) for both sexes, trajectories of TBMC and TBMD follow a curvilinear pattern between ages 8 and 30 yr; (2) predicted ages at peak TBMC and TBMD are from early to late 20s for both white males and females, with females reaching their peaks significantly earlier than males; and (3) concurrent height, weight, and BMI, but not habitual physical activity, exert significant effects on trajectories of TBMC and TBMD.