Stair climbing and risk of incident atrial fibrillation: Effect modulated by sex, genetic predisposition, and cardiorespiratory fitness

Background and aims: Stair climbing, a straightforward and impactful form of physical activity, has shown potential in reducing risks of cardiovascular disease and mortality. However, its association with the development of atrial fibrillation (AF) remains largely unexplored. Methods and results: 451,089 participants (mean age 56.5 years) without cardiovascular disease (year 2006-2010) were included from the UK Biobank study. Stair climbing data was collected through touchscreen questionnaire. AF cases were identified using ICD-10 code: I48 and were followed until February 1, 2022. Models adjusted for traditional cardiovascular risk factors. Over a median follow-up of 12.6 years, 23,660 (5.2 %) participants experienced new-onset AF. In multivariable-adjusted models, climbing 10-50, 60-100, 110-150, and >= 160 steps of stairs per day were associated with significant reductions in the risk of AF, compared to not climbing any stairs. The risk reduction appeared more pronounced in women than in men (P for interaction = 0.09). When compared to participants who climbed no stairs, the HRs for those who climbed 110-150 steps of stairs per day were 0.69 (95 % CI: 0.58-0.82) among those with low cardiorespiratory fitness, 0.71 (95 % CI: 0.57-0.88) among those with intermediate cardiorespiratory fitness, and 0.83 (95 % CI: 0.64-1.07) among those with high cardiorespiratory fitness. Conclusions: Climbing stairs was associated with a reduction in AF risks. Significant interaction between cardiorespiratory fitness and stair climbing associated with incident AF was observed. Findings suggest that promoting regular stair climbing could be a potential target for preventing AF onset.