Association between the frequency of achieving recommended daily step counts and a decline in quantitative ultrasound measurements in premenopausal and postmenopausal women: a 4-year prospective study of the Tohoku Medical Megabank Community-Based Cohort study

Achieving 7000 steps/day on ≥3 days/week significantly reduced the risk of decline in quantitative ultrasound measurements in premenopausal women, but not in postmenopausal women. Less frequent achievement (1-2 days/week) showed no significant association in either group. PURPOSE: To examine the association between the frequency of achieving the recommended daily step count (7000 steps/day) and the incidence of a decline in quantitative ultrasound (QUS) measurements among pre- and postmenopausal women. METHODS: In this prospective cohort study of the Tohoku Medical Megabank Community-Based Cohort, baseline and follow-up surveys were conducted between 2013-2016 and 2017-2021 (mean follow-up: 42.5 months). Participants were 3529 women (1013 premenopausal, 2516 postmenopausal). Daily steps were objectively measured using pedometers. The number of days per week achieving 7000 steps was categorized as Inactive (0 days), Low active (1-2 days), and Active (≥3 days). The outcome was the incidence of a decline in QUS measurements, defined as a QUS T-score ≤-2.5 or a self-reported diagnosis of osteoporosis. Adjusted risk ratio (RR) and 95% confidence interval (CI) were calculated using modified Poisson regression models, with the Inactive group as the reference. RESULTS: During follow-up, the outcome occurred in 70 premenopausal and 662 postmenopausal women. In premenopausal women, the Active group had a significantly lower risk of the outcome compared to the Inactive group (RR: 0.478, 95% CI: 0.271 to 0.843). In postmenopausal women, no statistically significant association was observed (RR for the Active group: 0.937, 95% CI: 0.807 to 1.088). CONCLUSION: The findings suggest that the association appeared to differ by menopausal status, achieving 7000 steps/day on ≥3 days/week was associated with a significantly reduced risk of a decline in QUS measurements in premenopausal women. However, for postmenopausal women, walking alone may be an insufficient strategy.