The effects of exercise on bone mineral density in postmenopausal women : a meta-analysis

Abstract

A meta-analysis was done to determine what effect exercise has on the bone mineral density (BMD) of the lumbar spine, proximal femur, and distal radius in postmenopausal women, utilizing data from 18 studies. Treatment effects (TE) were calculated for each of the skeletal sites, aerobic and strength training, as well as methods of BMD measurement (dual energy x-ray absorptiometry and dual photon absorptiometry). The resulting TEs found exercise, in general, to significantly increase (p c 0.05) the BMD of the lumbar spine (0.73%), and the proximal femur (0.35%); however, the distal radius showed a decrease (-0.91%) in BMD. When looking for the effect of aerobic versus strength training, significant (p c 0.05) increases in BMD were found in the spine and femur. Since positive changes were not seen in all sites, the benefits of exercise may be specific to the skeletal sites which the working muscles are attached. When the % change for exercise and control groups were analyzed separately, the exercise group increased 2.31% at the lumbar spine and 0.61% at the proximal femur. However, the exercise group decreased -2.21% at the radius. The control group decreased at the lumbar spine -1.09%, and at the femur -1.1 I%, however, increased at the radius 0.36%. The BMD % changes were significantly larger for the spine and femur, therefore, vigorous exercise along with resistance training may help slow the decrease in BMD as one ages.