Effect of Reproductive Factors on Bone Mineral Density in Postmenopausal Women

Hur, Jun Young; Kang, Ae Ra; Jin, Chan Hee; Shin, Jung Ho; Kim, Sun Haeng; Yuk, Jin Sung

Abstract

OBJECTIVES
The aim of this study was to evaluate the relations of reproductive factors including age at menarche, age at menopause, years since menopause, lifetime estrogen exposure, number of deliveries, and age at first and last delivery on bone mineral density (BMD) in postmenopausal women.
METHODS
Retrospective chart review was performed at Health promotion Center of Guro Hospital, Korea university medical center, from July 2008 to October 2009. A total of 217 postmenopausal women were included. BMD was measured at the lumbar spine and at the proximal femur using dual-energy X-ray absorptiometry (DXA).
RESULTS
Age, years since menopause, number of deliveries and age at the last delivery were negatively associated with lumbar spine BMD. Age, years since menopause and number of deliveries were negatively associated with femur neck BMD. However, having the first baby at later age was associated with high femur neck BMD. After adjustment for age and body mass index, age at the last delivery was negatively correlated with lumbar spine BMD. However, reproductive factors were not associated with femur neck BMD.
CONCLUSION
The present study suggests that among various reproductive factors, years since menopause, number of deliveries and age at the first and the last delivery were associated with BMD of postmenopausal women. After adjustment for age and body mass index, age at the last delivery was negatively correlated with lumbar spine BMD in postmenopausal women.