Abstract 12573: Step Count, Self-Reported Physical Activity, and Five-Year Risk for Incident Atrial Fibrillation

Background:Obesity and sedentary lifestyles are known risk factors for atrial fibrillation (AF). Wearable devices such as smartwatches present an opportunity to investigate relations between daily step count and AF risk.Hypothesis:Higher daily step count, as measured by wearable devices, will be associated with a smaller five-year risk of AF, as predicted by CHARGE-AF score.Methods:Participants from the electronic Framingham Heart Study (eFHS) utilized an AppleWatch. Individuals with diagnosed AF were excluded. Daily step count, watch wear time (hours, days), and self-reported physical activity were collected. Individual five-year risk of AF was estimated using The Cohorts for Heart and Aging Research in Genomic Epidemiology AF (CHARGE-AF) score. Relation between daily step counts and five-year predicted AF risk was examined with linear regression adjusted for age, sex, and wear time. Secondary analyses examined effect modification by sex and obesity (body mass index ≥30 kg/m2), as well as relation between self-reported physical activity and predicted 5-year AF risk.Results:We examined 932 eFHS participants (mean age 53±9 years, 61% female) with a median daily step of 7360 (25th-75thpercentile 5841-9060). Most participants (89.2%) had <2.5% CHARGE-AF risk. Every 1000 steps were associated with 0.08% lower CHARGE-AF risk (P<0.001). A stronger association was observed in men and individuals with obesity. In contrast, self-reported physical activity was not associated with CHARGE-AF risk.Conclusion:Higher daily step count was associated with lower predicted 5-year risk of AF, and this relation was stronger in men and participants with obesity. The utility of a wearable daily step counter for risk reduction for AF merits further investigation.