Regular exercise is associated with a lower risk of developing dementia in patients with a new diagnosis of atrial fibrillation: a nationwide population-based study

Abstract Introduction Regular exercise is known to decrease the risk of dementia. There is a paucity of information about the impact of the change of exercise habit on cardiovascular outcomes after a new diagnosis of atrial fibrillation (AF). We aimed to investigate whether regular exercise is associated with the risk of developing dementia in patients with AF. Methods Using the Korean National Health Insurance Service database, we enrolled patients with newly diagnosed AF who had undergone health screening between 2010 and 2016. The study population was divided into four groups based on the consistency of regular exercise before and after AF diagnosis: (1) persistent non-exerciser, (2) exercise starter, (3) exercise quitter, and (4) exercise maintainer. We investigated the association between exercise and the risk of dementia. Results A total of 126,555 patients were included (mean age 62.7 years, male 62.0%, and mean CHA2DS2-VASc Score 2.7). During a median follow-up duration of 3.0 years, 5,943 patients were newly diagnosed as dementia (1.57 per 100 person-years). Among patients with incident dementia, 4,410 patients had Alzheimer's dementia and 951 patients had vascular dementia (1.16 and 0.25 per 100 person-years, respectively). Persistent non-exerciser, exercise starter, quitter, and maintainer groups were 65.1%, 12.8%, 12.7%, and 9.4%, respectively. After multivariable adjustment, we found that exercise was associated with a lower risk of developing overall dementia. When compared to persistent non-exerciser, exercise starter and maintainer showed reduced risk of developing dementia (hazard ratio [HR] 0.80, 95% confidence interval [95% CI] 0.73–0.88 and HR 0.63, 95% CI 0.54–0.73, respectively, all p-value <0.0001), but exercise quitter showed no significant risk reduction (HR 0.95, 95% CI 0.88–1.03, Figure). Alzheimer's dementia showed consistent results: a 20% lower risk with exercise starter, and a 37% lower risk with exercise maintainer. Change of exercise habit, however, did not affect the risk of vascular dementia (all, p-value >0.05, Figure). Conclusions Regular exercise showed a lower risk of dementia in patients with new-onset AF. Starting exercise even after the diagnosis of AF was beneficial to patients who had little physical activity previously. These findings may support physicians to recommend that AF patients should start exercise or keep their physical activity to reduce the risk of dementia. Funding Acknowledgement Type of funding source: None