Walking Steps Prevents Loss Of Bone Mineral Density At The Femoral Neck In Postmenopausal Japanese Women

PURPOSE: Osteoporosis is defined as a skeletal disorder that increases the risk of fractures due to decreased bone strength. Prevention of osteoporosis is necessary to prevent the decline of activities of daily living and the quality of life of the elderly. The number of steps taken, as measured by a pedometer, has been used as a physical activity assessment by The National Nutrition Survey in Japan. However, it is unclear whether a large amount of walking steps has any positive effect on bone mineral density at the femoral neck (FN-BMD) in elderly women.The purpose of this study was to determine the relationship between FN-BMD and walking steps in postmenopausal Japanese women in a 5-year longitudinal study. METHODS: Participants were 381 postmenopausal women who had completed the Japanese Population-based Osteoporosis 2011-12 study and follow-up surveys in 2015-17 (mean 63.9 ± 7.5 years in 2011-2012). They were divided into two groups: women who were postmenopausal for less than 10 years and those who were postmenopausal for more than 10 years. FN-BMD was measured by dual X-ray absorptiometry. Steps/day were measured for a consecutive 7 days using a triaxial accelerometer. Multiple regression analysis was performed with FN-BMD, with its annual rate of change as the dependent variable, and items that correlated with FN-BMD as the independent variable. This study was approved by the Research Ethics Committee of Kitasato University (2020-010). RESULTS: Multiple regression analysis showed that walking was not a significant factor for FN-BMD in both studies, nor was the annual rate of change in FN-BMD evident in the less than 10 year postmenopausal group. On the other hand, after adjusting for potential confounding factors, walking was a significantly positive factor for FN-BMD at follow-up and for annual percent changes in FN-BMD in the more than 10 year postmenopausal group (standardized regression coefficient = 0.123, p < 0.05. 0.128, p < 0.05, respectively). CONCLUSIONS: The effect of walking on FN-BMD is greater in postmenopausal elderly women. Maintenance of daily walking may have a positive effect on FN-BMD, contributing to the prevention of osteoporosis.