Factors affecting bone loss around menopause in women without HRT: a prospective study

Abstract

Objectives: The present study evaluated the effects of menopause and other putative bone loss modifying factors on bone mineral density (BMD) change. Methods: The study population, 396 healthy women aged 48–59 years with no history of hormone replacement therapy (HRT) use or any bone affecting disease or medications, was selected from a random sample ( n=2025) of the OSTPRE-study cohort ( n=13 100) in Kuopio, Finland. BMD at lumbar spine (LS) and three areas of proximal femur (femoral neck (FN), Ward's triangle (W), trochanter (T)) was measured with dual X-ray absorptiometry at baseline in 1989–1991 and at 5 years in 1994–1997. Results: 116 women who reported the beginning of menopause during the follow-up (perimenopausal) had the greatest mean annual bone loss (−1.22%/year (LS), −0.87% year (FN), −1.14%/year (W), −0.36%/year (T)). In women under 5 years postmenopausal at baseline (early postmenopausal, n=172) bone loss rate was significantly lower than in perimenopausal women. In women over 5 years postmenopausal at baseline (late postmenopausal, n=108) bone loss rate was significantly further decreased only at lumbar spine. In peri- and postmenopausal women the annual BMD change was best described as a trinomial function of the duration of menopause at all sites ( P<0.03). Of the life-style factors studied protective effects were found in weight increase in both spinal and femoral bone ( P=0.010/ P<0.001), high baseline weight in spine ( P<0.001) and high grip strength in femoral neck ( P=0.002). Conclusion: The beginning of menopause is accompanied by significant bone loss, which decreases in later menopause. Few other physiological and life-style factors were found to significantly contribute to this phenomenon.