Association between frequency of meeting daily step thresholds and all-cause mortality and cardiovascular disease in older women

Objective To examine the associations between the number of days per week achieving various daily step thresholds and all-cause mortality and cardiovascular disease (CVD) incidence in older women. Methods We conducted a prospective cohort study of 13 547 women free of CVD and cancer (mean age 71.8 years). We included participants who wore an ActiGraph GT3X+ accelerometer for 7 consecutive days between 2011–2015 and were subsequently followed for mortality through 2024. Women were classified by the number of days per week achieving step thresholds of ≥4000, ≥5000, ≥6000 or ≥7000 steps/day. Cox proportional hazards regression estimated hazard ratios (HR) and 95% confidence intervals (95% CI) for all-cause mortality and CVD incidence, adjusting for lifestyle behaviours and comorbidities. Results During a median follow-up of 10.9 years, 1765 women (13.0%) died and 781 (5.1%) developed CVD. Achieving ≥4000 steps/day on 1–2 and ≥3 days/week was associated with lower mortality risk compared with 0 days/week (adjusted HR 0.74 (95% CI 0.65 to 0.86) and 0.60 (95% CI 0.53 to 0.68), respectively). For CVD, corresponding results were 0.73 (95% CI 0.58 to 0.92) and 0.73 (95% CI 60 to 0.89), respectively. An inverse curvilinear dose-response relationship was observed for mortality, such that with higher step thresholds (5000, 6000 or 7000), the risk of mortality further declined modestly. With additional adjustment for mean daily steps, associations were attenuated to the null. Conclusions Among older women, achieving ≥4000 steps/day on even 1–2 days/week was associated with lower mortality and CVD, while more steps were associated with even better outcomes. A greater number of steps, regardless of daily patterns, is associated with better health outcomes.