VARIABILITY OF VERTEBRAL AND FEMORAL POSTMENOPAUSAL BONE LOSS - A LONGITUDINAL-STUDY

The rate of postmenopausal bone loss varies considerably between indiv iduals and it has been suggested that about 1 in 3 women loses signifi cant amount of bone nineral in the forearm. The rate of vertebral and femoral bone loss was determined by dual-energy X-ray absorptiometry t hroughout two consecutive 22-month periods, in 93 healthy women two ha d passed a natural menopause 6-60 months earlier, In all cases the bon e changes were normally distributed, ranging from -6.9% to +2.8% per y ear in the spine and from -7% to +4.5% per year in the femur, No signi ficant relationship was found between the two fractional rates of bone loss. When the women were stratified into three groups according to t heir individual rate of bone loss, we found that only 20%-47% retained their first classification during the second period of fellow-up. In particular, less than 10% of the women showed a rapid rate of bone los s throughout the study. We conclude that spontaneous vertebral and fem oral bone loss exhibit a great variability within the first postmenopa usal years and that only a small minority of women sustain a fast rate of bone loss over several years, These results raise tile question as to whether the evaluation of individual rates of bone loss at menopau se might be useful in the identification of women at higher risk of os teoporosis.