Whole body bone mineral accretion in healthy children and adolescents

Data on accretion in bone size and bone mineral content (BMC) are needed to evaluate bone mineralisation during childhood. Whole body bone mineral con tent (BMC) and bone area (BA) were determined by dual energy x ray absorpti ometry (Hologic 1000/W) with a one year interval in healthy girls (n = 192) and boys (n = 140) aged 6-19 years. Annual accretion in BMC (Delta BMC (g/ year)) and BA (Delta BA (cm(2)/year)) according to sex and pubertal stages were calculated. Delta BA and Delta BMC were highly significantly associate d with pubertal stages in girls and boys. Gentile curves for Delta BA and D elta BMC according to sex and age were constructed using the LIMS method. P eak Delta BA and Delta BMC values were reached earlier in girls (12.3 and 1 2.5 years, respectively) than in boys (13.4 and 14.2 years, respectively). The Delta BA peak tvas dissociated in time from the Delta BMC peak, indicat ing that increase in bone size occurs before increase in bone mineral conte nt. Assuming that 32.2% of BMG consist of calcium, the median (90th centile ) annual bone calcium accretion in pubertal stage III was 220 mg/day (302) and 317 mg/day (386) for girls and boys, respectively. To obtain an average bone calcium accretion, a high calcium absorption is needed during puberty . This may have implications for dietary calcium requirements at this time.