Magnitude and determinants of premenopausal bone loss.

Bone loss prior to menopause may contribute to a woman's risk for fracture due to osteoporosis later in life. Most, but not all, longitudinal and cross-sectional studies suggest that bone mass decreases prior to menopause. This bone loss may be prevented by calcium supplementation. Heredity, exercise and menstrual status also have an impact on bone mass. Prevention of bone loss prior to menopause will allow women to enter menopause with a greater bone mass reducing their risk of subsequent fracture.