Abstract 34: A Quarter of a Mile More Steps Are Incrementally Associated With Lower Risk of Proximal CVD Events Among Older Adults: Atherosclerosis Risk in Communities (ARIC) Study

Abstract

Introduction: Steps are an easily interpretable metric that could be used in patient-clinician communication regarding the health benefits of physical activity for cardiovascular disease (CVD). However, most studies are conducted in younger populations with daily steps goals (e.g., 10,000 steps) that may be unsuitable for older adults. Hypothesis: We tested the hypothesis that more daily steps are associated with lower risk of proximal CVD events (within 3.5 years) among older adults (≥70 years). Methods: We analyzed a subsample of participants from the ARIC study visit 6 (2016-17) who wore an accelerometer (ActiGraph GT3X) on the waist ≥3 days for ≥10 hr/day. Daily steps were analyzed continuously and by quartiles. Adjudicated outcomes, through December 2019, included fatal and non-fatal CVD events (coronary heart disease, stroke, and heart failure). Multivariable adjusted Cox proportional hazard models were used to estimate the hazard ratio of CVD events across step measures, adjusted for age, sex, race, education, body mass index (BMI), and accelerometer wear time. Results: Among the 452 adults with step data (mean age = 78.4; 59% women; 20% Black), 7.5% (34/452) had a CVD event over 1,269 person-years of follow-up. Mean (SD) step count was 3447 (1796) steps/day. CVD cumulative incidence was highest among those in the least active step quartile (Q1: <2077 steps/day) (11.5%) compared to the most active quartile (Q4: ≥4453 steps/day) (3.5%). Every 500 steps/day (about 1/4 mile) was associated with a 14% reduced risk of a CVD event (HR = 0.86, 95% CI: 0.76, 0.98). Further, compared to participants in Q1, participants in Q4 had a 77% reduced risk of a proximal CVD event (HR = 0.23, 95% CI: 0.07, 0.83). Cubic spline HR are presented (figure). Conclusions: In this community-based cohort of older adults, every 500 steps (~1/4 of a mile) was associated with a 14% lower risk of a CVD event over 3.5 years of follow-up. Additional follow-up is needed to determine if higher steps prevent or delay CVD or if low steps serve as a biomarker of underlying disease.