Physical activity, physical fitness, and osteopenia in postmenopausal Taiwanese women

Background and purpose: The purpose of this cross-sectional study was to investigate whether physical activity level and physical fitness parameters differ between postmenopausal Taiwanese women with normal and subnormal bone mineral density (BMD). Methods: Seventy-six postmenopausal women aged from 42 to 65 years participated in this study. Women taking medication that might influence BMD measurements were not included. The BMDs of the lumbar spine (L2-4) and right femoral neck were measured using dual energy x-ray absorptiometry. Thirty-one women with both BMD values within the normal ranges (1.055 ± 0.092 g/cm2 for the spine and 0.845 ± 0.088 g/cm2 for the fight femoral neck) of premenopausal Chinese women served as the normal density group. Another 43 women with both BMD values more than one standard deviation below the normal value (0.760 ± 0.089 g/cm2 for the spine and 0.656 ± 0.052 g/cm2 for the femoral neck) were recruited as the osteopenic group. Physical activity level was assessed with a 7-day recall questionnaire. Physical fitness assessment included tests of flexibility, muscular strength, endurance, body composition, and cardiopulmonary fitness. A multiple linear regression model adjusted for age, body weight, height, and years since menopause was used. Results: The results revealed that energy expenditure and maximal oxygen consumption were significantly lower in the osteopenic group than in the non-osteopenic group (p < 0.05), while flexibility, body composition, muscle strength and muscular endurance did not differ significantly between the two groups (p > 0.05). Conclusions: These findings indicate that physical activity may play a major role in BMD levels in postmenopausal women in Taiwan. Future studies should emphasize the effect of physical exercise training on BMD in postmenopausal women.