Attainment of maximal peak bone mass (PBM) at skeletal maturity ia critical in the prevention of osteoporosis. In an on-going atudy, changes in calcium accretion in adolescent females on an intake of 1364 tng Ca/d were determined. Subjects (n6), initially aged 12-15y, participated in a 21d balance study which was repeated after 3y. In both studies, clinical indicators of bone turnover were measured. Bone density (DEXA) was measured at 17mo intervals. Due to increases in urinary and fecal Ca excretion, the average Ca retention declined significantly (P<0.05) from 288 ± 229mg/d in early puberty to 60 ±89mg/d in late puberty. Balance variables in late puberty were compared with young adults (n=ll) who participated in the initial balance study under the same controlled conditions, and no significant difference wan found (P0.95). Skeletal calcium content increased to 89.5% of young adult values and the rate of accretion declined with age. Between the 2 studies, all biochemical marker concentrations decreased, indicating a decline in the rate of bone remodeling. These results emphasize the importance of puberty in skeletal development. By late adolescence (15-18 years), calcium retention is at adult levels and the best opportunity for enhancing peak bone maae has probably passed.
ASJC Scopus subject areas
- Molecular Biology