Bone mineral density and metabolism at an early stage of menopause when estrogen and calcium supplement are not used and without the interference of major confounding variables.

Objectives: To measure bone mineral density (BMD) and to screen for early biochemical abnormalities in bone mineral metabolism in the first five years of natural menopause when estrogen and calcium supplement are not used and in the absence of major confounding variables.

Setting: Two homogeneous and comparable groups (n = 30) of healthy pre- and postmenopausal Caucasian women living in a northern region (latitude 46 degrees N) were recruited during the mid-Spring/Summer season in a cross-sectional design.

Methods: Volumetric apparent BMAD (g/cm(3)) was calculated from areal BMD (g/cm(2)) which was evaluated by dual energy X-ray absorptiometry (Lunar) at both axial and peripheric (femur) sites using two sets of reference values (WHO criterion expressed as T-score and absolute values of areal density) in combination to bone specific biochemical measurements.

Results: BMD and BM(A)D were significantly lower in postmenopausal women for all lumbar sites, but not for Ward's triangle and any other femoral sites whereas free deoxypyridinoline (Dpd), urinary biochemical marker of bone resorption, was markedly (p < 0.0001) greater. Their serum calcium and phosphate were significantly higher without a difference in 1,25(OH)(2)D(3) and PTH. The prevalence of osteopenia in pre- and postmenopausal women was about 2-fold lower in both groups (26.6 and 46.9%, respectively) when lumbar (L) spine and femur neck were combined and using the criteria based on reference values of areal density instead of T-scores.

Conclusions: The present study showed that the negative effects of estrogen deficiency on BMD and bone metabolism in early menopause occurred independently of the effect of major calcitropic hormones. Bone loss affects a non negligible proportion of premenopausal women. The prevalence of osteopenia in pre- and postmenopausal women varied according to the criterion used and anatomic site.