Objective: To investigate in healthy normal Dutch women the age-associated changes in bone mineral density (BMD) and the effect on bone mass of the menopause and potential risk factors.
Methods: In 260 healthy Dutch women BMD was measured in the lumbar spine and three regions of the proximal femur (Ward's triangle, femoral neck and trochanter), using dual energy X-ray absorptiometry (DXA). The subjects were interviewed using a structured questionnaire on age, reproductive history and gynaecological status, height, weight and consumption of tobacco and alcohol.
Results: In 125 premenopausal women a small age-related bone loss was observed at both the lumbar spine and proximal femur, while in postmenopausal women (n = 135) a 2-3 times higher age-related loss was observed. Expressed in years since the menopause this postmenopausal loss was found to be exponential (p < 0.001). After adjustment for age there appears to be a relationship between actual age of menopause and BMD at the lumbar spine and femoral neck. After adjustment for age and actual age of menopause we observed a small negative effect of breastfeeding, whereas parity, current alcohol use and smoking showed no additional effect on BMD in this cohort. For all women (n = 260) a highly significant correlation between BMD and body mass index was found.
Conclusions: In healthy Dutch women we observed a small premenopausal and an accelerated postmenopausal bone loss in both the lumbar spine and proximal femur. Except for breastfeeding, no other risk factors could be identified.