TIMING OF PEAK BONE MASS IN CAUCASIAN FEMALES AND ITS IMPLICATION FORTHE PREVENTION OF OSTEOPOROSIS - INFERENCE FROM A CROSS-SECTIONAL MODEL

To determine the timing of peak bone mass and density, we conducted a cross-sectional study of bone mass measurements in 265 premenopausal C aucasian females, aged 8-50 yr. Bone mass and bone mineral density wer e measured using dual X-ray absorptiometry and single-photon absorptio metry at the spine (anteroposterior, lateral), proximal femur, radius shaft, distal forearm, and the whole body. Bone mass parameters were a nalyzed using a quadratic regression model and segmented regression mo dels with quadratic-quadratic or quadratic-linear form. The results sh ow that most of the bone mass at multiple skeletal locations will be a ccumulated by late adolescence. This is particularly notable for bone mineral density of the proximal femur and the vertebral body. Bone mas s of the other regions of interest is either no different in women bet ween the age of 18 yr and the menopause or it is maximal in 50-yr-old women, indicating slow but permanent bone accumulation continuing at s ome sites up to the time of menopause. This gain in bone mass in preme nopausal adult women is probably the result of continuous periosteal e xpansion with age. Since rapid skeletal mineral acquisition at all sit es occurs relatively early in life, the exogenous factors which might optimize peak bone mass need to be more precisely identified and chara cterized.