Risk factors associated with peri- and postmenopausal bone loss: does HRT prevent weight loss-related bone loss?

In the present study we evaluated the risk factors associated with peri- and postmenopausal bone loss and the effect of hormone replacement therapy (HRT) on weight-loss-related bone loss. The study population, 940 peri- and postmenopausal women, was selected from a random sample (n = 2025) of the OSTPRE study cohort (n = 13 100) in Kuopio, Finland. Bone mineral density (BMD; g/cm(2)) at the lumbar spine and femoral neck, and body weight, were measured at baseline in 1989-91 and at 5-year follow-up in 1994-97 by trained personnel. Five hundred and forty-seven women had never used HRT and 393 women used part-time or continuous HRT during follow-up of 3.8-7.9 years (mean 5.8 years). Similarly, of the 172 weight losers, 97 had never used HRT while 75 used it during follow-up. According to multiple regression analysis on the total study population (n = 940), HRT use, years since menopause and weight increase significantly predicted lower annual bone loss at both the lumbar spine and femoral neck (p < 0.005). Low baseline weight and higher age predicted higher bone loss only at the lumbar spine (p < 0.001) and high grip strength predicted lower bone loss only at the femoral neck (p = 0.021). In a sub-analysis on weight losers, weight loss predicted greater bone loss in HRT non-users (p < 0.05), whereas this was not observed in HRT users. These results remained similar after adjustment for age, weight, height, calcium intake, duration of menopause, baseline BMD and bone-affecting diseases/medication. In conclusion, the transition to menopause, HRT and weight change are the most important determinants of bone loss at both the lumbar spine and femoral neck. Furthermore, HRT seems to be effective in prevention of weight loss related bone loss.