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.