Sedentary Behavior and Atrial Fibrillation in Older Women: The OPACH Study

BACKGROUND: Sedentary behavior is associated with cardiovascular disease, but its association with incident atrial fibrillation is not well studied. Our aim was to measure the association between objectively measured sedentary behavior and incident atrial fibrillation. METHODS AND RESULTS: Sedentary behavior was measured by a triaxial accelerometer worn on a belt for 1 week. Incident atrial fibrillation was ascertained from Medicare claims. The associations between total sedentary time (or patterns of sedentary behavior) and incident atrial fibrillation were assessed using Cox proportional hazards models adjusted for demographic and clinical covariates. Among 2675 participants (mean age, 78.2 years), there were 268 (10.0%) cases of incident atrial fibrillation at a rate of 31 cases per 1000 person‐years. Greater total sedentary time was associated with a higher risk of incident atrial fibrillation after adjustment for age, race and ethnicity, body mass index, education, smoking history, hypertension, diabetes, stroke, heart disease, and other chronic conditions (quartile 4 versus quartile 1: hazard ratio, 1.20, [95% CI, 0.81–1.78]; P for trend=0.05). After adjusting for physical function and self‐rated health, this was no longer statistically significant. Both longer mean sedentary bout duration and more continuous sedentary periods (versus frequent breaks in sedentary time) were also associated with higher risks of incident atrial fibrillation, but these associations were also attenuated with serial adjustment. CONCLUSIONS: Total sedentary time and prolonged patterns of sedentary accumulation were associated with a higher risk of atrial fibrillation in this prospective study of community‐dwelling older women, but these associations were attenuated by adjustment for physical function and self‐reported health. This suggests that associations between sedentary behavior and atrial fibrillation may be attributable to global measures of overall function and health.