Changes in bone mineral content of the axial skeleton in relation to aging and the menopause. Results from a longitudinal population study of women in Gothenburg, Sweden.

Patterns of bone loss in the axial skeleton have been studied in a sample of Swedish women participating in a longitudinal population study which was started in 1968. In 1976, the mineral content of the lumbar spine (predominantly trabecular bone) was measured in vivo in 130 women by dual photon absorptiometry. Premenopausal or recently postmenopausal women were compared with women of identical age who had been postmenopausal for a long time. The first group was found to have significantly higher values of bone mineral content. Five years later, in 1981, the same women were re-examined with identical techniques. A slight decrease in bone mineral content with age was found in postmenopausal women. The findings were mostly in agreement with those of the first cross-sectional study, with bigger differences in bone mineral content between women of different menstrual status than between women of different age. In addition, the lower values in women with early menopause compared to those with late menopause remained in spite of increasing age.