[Vertebral bone loss in perimenopause. Results of a 7-year longitudinal study]

Rapid bone loss after menopause is generally recognized although the exact chronology of the events, particularly in relation to onset of amenorrhea, remains poorly understood. We assessed bone loss in perimenopausal women over a 7-year period.

Twenty-one women with an uneventful past history were enrolled before menopause and followed until menopause had been completely established. Vertebral bone density was measured by biphotonic absorptiometry annually over two 2-year periods. Individual variations in bone density were calculated according to onset of menopause.

Bone loss in the vertebral body increased during the two years preceding menopause (-1.6 +/- 1.5% per year), reached a peak during the first three post-menopausal years (-2.4 +/- 1.6% per year), and then fell off (-1.2 +/- 1.4% per year).

Bone loss was independent of calcium intake and appeared to be related mainly to characteristic hormone changes during the perimenopausal period. These findings raise the question as to the need and means of prevention.