[Physiological and pathological aging in bone--contribution of risk factors to bone loss with aging]

This study was performed to investigate the mechanism of the pathological ageing of bone, evaluating the effect of risk factors for osteoporosis on bone mineral density in elderly women (n = 108), ovariectomized (OVX; n = 86) and hysterectomized (HX; n = 75) middle-aged women. Possible risk factors such as family history, physique, reproductive function, calcium intake, physical activity and past history were studied by using questionnaires. Parameters of bone metabolism such as serum Ca, P, Al-p, parathyroid hormone (PTH), osteocalcin, vitamin D metabolites and urinary Ca/creatinine ratio were also measured. Spinal bone mineral densities (BMD) were determined by dual energy X-ray absorptiometry (DPX, Lunar). By multiple regression analysis, body height, PTH and serum Ca in HX group, alcohol consumption, serum Al-p, Ca, PTH, 1,25(OH)2D and 25(OH)D in OVX group were independent significant predictors for lumbar BMD. On the other hand, serum levels of Al-p and urinary Ca/creatinine ratio were independent, significant, but weak predictors in the elderly group. Thus, in the elderly group, it was difficult to predict specific factors affecting BMD when compared with the HX and OVX groups. Moreover, the coefficient of determination was smaller in the elderly group (r2 = 0.156) than those of the HX group (r2 = 0.205) and OVX group (r2 = 0.251). In elderly women, the frequencies of persons who dislike milk and who have low body weight (less than mean - SD) in low BMD with fractures were higher than those in normal BMD without fracture.(ABSTRACT TRUNCATED AT 250 WORDS)