BONE-MINERAL ACQUISITION DURING ADOLESCENCE AND EARLY ADULTHOOD - A STUDY IN 574 HEALTHY FEMALES 10-24 YEARS OF AGE

Low bone mass is known to be associated with an increased risk of frac tures. Osteoporosis prevention by maximizing bone mass will be crucial and requires a better knowledge of bone mass acqusition during adoles cence. Bone mass was assessed in 574 healthy volunteer females aged 10 -24 years. Spine bone mineral density (BMD) in anteroposterior (AP L2- 4) and lateral (LAT L3) views was measured using dual-energy X-ray abs orptiometry (DXA) and AP bone mineral content (BMC) was calculated. At the same time, spine AP-BMD (L2-4) was evaluated in 333 normal menstr uating women, aged 27-47 years. Bone values, osteocalcin and IGF-1 ser um concentrations were correlated with chronological age, skeletal age , pubertal stages and time after menarche. In this cross-sectional stu dy, AP-and LAT-BMD and BMC increased dramatically between skeletal age s 10 and 14 or until the first year after menarche. Between 14 and 17 skeletal years of age, AP-BMD and BMC increased moderately, whereas LA T-BMD remained unchanged. After skeletal age 17, or the fourth year af ter menarche, there was no significant increase in BMD or BMC, and the ir values did not differ from those of menstruating women. A serum ost eocalcin peak was observed at skeletal ages 11-12 or at stage P3, wher eas IGF-1 peaked at 13-14 skeletal years of age or at P3 and the first year after menarche. Eighty-six per cent of the adult bone mass of th e spine is acquired before skeletal age 14 or the secund year after me narche; therefore osteoporosis prevention programs will be particularl y effective before that age.