Abstract

The aim of this study was to examine lifestyle risk factors for low bone mass, falls and fractures, and to determine the effect of 30-month exercise trial on bone mass, balance, muscle strength and gait in elderly women. Reliability of an inclinometric method for assessing postural sway was evaluated.

Data on risk factors, falls and fractures were collected by questionnaires, and calcaneus and radius bone mass were measured from 1,222 women. Lifetime physical activity, low occupational physical activity, type 2 diabetes, hypertension, hormone replacement, thyroid hormone and thiazide use were associated with increased bone mass, while low current physical activity, high coffee intake and late menarche were associated with low bone mass in lean women. Factors associated with fractures were: low lifetime habitual physical activity, diabetes, living alone and calcaneum bone mass.

One hundred and sixty women with low femoral neck bone mass were randomly assigned to the exercise group (n = 84) or to the control group (n = 76). The outcomes included radius, proximal femur and calcaneus bone mass, postural sway, muscle strength, gait speed and endurance. Bone mineral density (BMD) at proximal femur decreased in the control group, while no change occurred in the exercise group. Mean trochanter bone mineral content (BMC) decreased more in the control group. The women in the exercise group improved their performance in walking speed and endurance, body sway and leg strength compared to the control group. There were six falls that resulted in fractures in the exercise group and 16 in the control group. The inclinometric method proved to be reliable.

In conclusion, lifestyle factors are determinants of bone mass in lean elderly women. Long-term exercise has a site-specific effect on BMC but not on BMD in elderly women. Weight-bearing exercise can modify risk factors for fractures, and may even prevent fall-related fractures in elderly women.