Rate of spinal trabecular bone loss in normal perimenopausal women: CT measurement.

Age-related bone loss in women may begin at any time following attainment of peak skeletal maturity bone mass. The rate of bone loss may accelerate near the time of menopause and continue for several years thereafter. Women with low baseline bone mass and women who are fast bone losers are potentially at risk for early spinal osteoporosis. In a prospective longitudinal study, spinal trabecular bone mineral content (BMC) of 83 healthy women, 47-53 years old, was measured with use of computed tomography (CT) at 0, 12, 24, and 36 months. Fifty-four of these same women had a fifth measurement at 48 months. In 51 women the rate of bone loss was less than or equal to 2% per year (average 1.96%; normal bone losers); in 32, it was more than 2% per year (average 5.61%; fast bone losers). CT studies can identify women with low spinal trabecular BMC and/or fast bone loss--women likely to be at increased risk for early spinal osteoporosis. This information may be useful in selection of candidates for vigorous preventive measures, including estrogen replacement.