Impact of atrial fibrillation on all-cause mortality in veteran endurance athletes compared with the general population: a prospective cohort study with 16 years follow-up

Background Both physical inactivity and prolonged exposure to endurance training are associated with increased risk of atrial fibrillation (AF). AF is the most prevalent cardiac arrhythmia in athletes, predominantly occurring in male veteran endurance athletes. While AF is linked to increased morbidity and mortality in the general population, the impact of an AF diagnosis on all-cause mortality in veteran endurance athletes remains uncertain. Purpose The aim of this study was to explore the association of AF with all-cause mortality during long term follow-up in veteran endurance athletes, in comparison with the general population. Methods A total of 4,564 individuals aged ≥65 years were included from two prospective Norwegian cohort studies: 549 veteran endurance athletes (46 women) recruited in 2009-10 and 4,015 individuals (2,148 women) from a population-based cohort study that were considered representative of the general Norwegian population (2006–07). Athletes were non-elite participants still competing in an annual 54km long cross-country ski race in Norway. Baseline AF was self-reported by questionnaires. All-cause mortality was obtained through linkage to national death registries. Participants were followed from baseline until death or administrative censoring on 31 December 2025. Mortality was analysed using Cox proportional hazards models adjusted for age, sex, education, hypertension treatment, diabetes, smoking, and ≥1 cardiovascular disease (angina, myocardial infarction or stroke). Results The included endurance athletes (mean age 68.8 years) had practiced endurance training for more than three decades on average and had participated in a long-distance ski race for an average of 16 years. Compared to the general population, athletes had a low prevalence of cardiovascular risk factors and co-morbidities, but the prevalence of AF was comparable between the two cohorts (13.4% in athletes vs. 11.0% in the general population). During a median follow-up of 16 years, 2,382 deaths occurred, 2,272 in the general population and 110 in the athlete cohort. The athletes had significantly lower all-cause mortality compared with the general population (adjusted hazard ratio [aHR] 0.37, 95% confidence interval [CI] 0.30–0.46). While AF was associated with increased all-cause mortality in the general population (aHR 1.67, 95% CI 1.46–1.91), mortality was not significantly increased in athletes with AF compared to athletes without AF (aHR 1.23, 95% CI 0.70–2.14). We found no significant interaction between AF and athlete status (p for interaction = 0.42). Conclusions This study suggests that the high prevalence of AF seen in endurance athletes does not translate into increased all-cause mortality during long term follow-up. Moreover, we observed that the overall mortality was 63 % lower in endurance athletes compared to the general population, supporting the beneficial effect of regular endurance training on all-cause mortality.