Bone mass and risk factors for bone loss in perimenopausal Danish women

Abstract

Objectives. To determine risk factors for low bone mass at menopause and risk factors for subsequent bone loss in the following period. Design. A cross-sectional study and a 2-year prospective follow-up. Setting. The catchment area of Sundby Hospital in Copenhagen. Subjects. Four hundred and thirty-three women aged 45-58 years, with amenorrhea for 3-24 months, of whom 87 were followed for a 2-year period. Measurements. Registration of life- style and anthropometric variables, reproductive history, and family history of fractures. Total body bone mineral content (BMC) was measured with dual energy X-ray absorptiometry. Results. By means of multiple regression analysis height, body weight, and length of reproductive period were found to be positively related to whole body BMC (P < 0.001), whilst a negative relationship was found to age (P < 0.001), smoking (P < 0.001), and family history of fractures (P < 0.005). In the longitudinal study, only body weight at the inclusion (P = 0.005) and subsequent changes in body weight and fat mass (P < 0.001) were related to the changes in bone mass. Conclusion. The most significant predictors for bone loss were changes in body weight and fat mass. Hence, weight loss is a risk factor for bone loss in the early postmenopausal period, whereas weight gain seems to preserve bone.