Accelerated decrease in bone mineral density in women aged 52-57 years.

Bone mineral density (BMD) has been known to decline in middle-aged and elderly individuals, but when this decline begins and the rate at which it occurs remain unclear. We thus undertook this study to examine the association between BMD and age by their mean values in women visiting the Shimane Institute of Health Science for medical examination. We performed dual energy x-ray absorptiometry measurement of lumbar vertebrae in 1,167 women, and of the entire skeleton in 1,038 women. The ages of subjects ranged from 30 to 70 years. We found that the mean value of whole-body and lumbar BMD changed little in the age range of 30-51 years, and any change after 58 years was a gradual decrease, unlike the sharp decrease found between 52 and 57 years of age. The effects of endocrine kinetics may be reflected in women by the decrease of bone density relative to age. In conclusion, BMD declines more rapidly in women within the age range of 52-57 years than in those 58 years and over. This regression line is considered useful in predicting BMD of whole-body skeleton and lumbar vertebrae relative to age for the prevention of osteoporosis in women.