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Endurance exercise and atrial fibrillation. Atrial fibrillation among Norwegian veteran endurance athletes and the association between endurance exercise and risk of atrial fibrillation

Year: 2015
Type: dissertation
Study design: Observational Study
Abstract: Background Atrial fibrillation (AF) is the most common clinically relevant cardiac arrhythmia. AF is associated with reduced functional capacity and other symptoms, drug use, poor subjective health, increased risk of ischemic stroke and increased mortality. Physical activity (PA) reduces the risk of cardiovascular diseases and has multiple beneficial health effects, but male endurance athletes seem to have an increased risk of AF. Few studies, however, have investigated the association between prolonged endurance exercise and the risk of AF, and this association has not been studied in women previously. The number of individuals aged >40 years that engage in endurance sports events is increasing, but few studies have investigated the association between endurance sport practice and risk of AF in veteran athletes. Furthermore, AF and its consequences have been just sporadically described in veteran athletes previously. The main aims of this thesis were 1) to investigate endurance sport practice as a risk factor for AF in veteran athletes (paper I), 2) to investigate the association between prolonged regular endurance exercise and risk of AF in men (paper II), 3) to investigate the association between prolonged regular endurance exercise and risk of AF in women (paper III), and 4) to characterize AF and investigate PA, endurance exercise, symptoms, drug use and subjective health in veteran athletes with AF (paper IV).\nMethods Paper I is based on the Birkebeiner Ageing Study. In this cross-sectional study, 509 out of 607 invited men (84%) aged =65 years who took part in the 54-kilometer Birkebeiner cross-country ski race in 2009 or 2010 participated. These veteran athletes were compared to 1768 out of 2757 invited men aged =65 years (68%) participating in a population-based health study. The main outcome AF was self-reported by questionnaires. The main exposure was endurance sport practice, defined as participating in the Birkebeiner race. We calculated adjusted risk differences (aRDs) for AF with 95% confidence intervals (CIs) using a linear regression model. In the papers II and III, we investigated the association between prolonged regular endurance exercise and the risk of AF in men and women, respectively. These papers are based on a second study, the Birkebeiner Atrial Fibrillation Study. The study population of this retrospective cohort study comprised two distinct cohorts: 1) Veteran athletes aged =53 years who had participated in the Birkebeiner race in 1999, and 2) participants in the same group in a population-based health study. In total, 5390 out of 7500 invited men and women (72%) took part in the Birkebeiner Atrial Fibrillation Study. In the study of men (paper II), the main outcome was AF and atrial flutter (AFL) confirmed by electrocardiograms (ECGs) in a review of medical records. Due to the low number of confirmed AF cases among female participants, self-reported AF was the main outcome in the analysis of women (paper III). The main exposure, years of regular endurance exercise was self-reported by questionnaires. Regular endurance exercise was defined as exercise for at least 30 minutes =3 times per week with the purpose of increasing physical endurance capacity. Adjusted odds ratios (aORs) for AF with CIs were calculated using weighted logistic regression models. Also paper IV is based on the Birkebeiner Atrial Fibrillation Study. In this study, we characterized AF in detail among 140 veteran skiers and 118 individuals from the general population with confirmed AF. Furthermore, we investigated engagement in PA and endurance exercise after the onset of AF, palpitations, functional capacity, drug-use and subjective health in veteran athletes with AF and in the general AF population.\nResults The prevalence of self-reported AF in the Birkebeiner Ageing Study was 13.2% in the veteran athletes and 11.6% in the men from the general population. After multivariable adjustment for age, height, body mass index (BMI), coronary heart disease (CHD), hypertension, diabetes mellitus, smoking, alcohol consumption, leisure-time PA during the past year and education, endurance sport practice was associated with an added risk of AF of 6 percent points (pp) (aRD 6.0 (CI 0.8-11.1)), corresponding to an aOR of 1.90 (CI 1.14-3.18). In the Birkebeiner Atrial Fibrillation Study, the prevalence of self-reported AF was 12.5% among the male veteran athletes. After multivariable adjustment for age, height, concomitant heart disease, hypertension, diabetes mellitus and cohort affiliation, years of regular endurance exercise was associated with a gradually increased risk of both AF and AFL. Per 10 years of exercise, the aOR was 1.16 (CI 1.06-1.29) for AF and 1.42 (CI 1.20-1.69) for AFL. In stratified analyses, the associations were significant both in the veteran athletes and in the men from the general population. Men who had exercised regularly for =40 years had an aOR for AF of 1.94 (CI 1.19-3.14)) compared to men who had never exercised regularly. The prevalence of self-reported AF among female veteran skiers was 8%. After multivariable adjustment for age, BMI, concomitant heart disease, hypertension, diabetes mellitus and cohort affiliation, women who had exercised regularly for =40 years had an increased risk of AF of borderline significance (aOR 2.18 (CI 0.94-5.06)) compared to women who had never exercised regularly. Among veteran athletes with AF, 52% had paroxysmal, 23% had persistent and 24% had permanent AF. AF was associated with poor subjective health, but 89% of the veteran athletes were physically active and 64% engaged in regular endurance exercise after the onset of AF. While 59% had experienced palpitations during the past year, 32% reported reduced functional capacity. Two out of three with AF and an estimated CHA2DS2-VASc score =2 used oral anticoagulants (OACs).\nConclusions In conclusion, 1) endurance sport practice seemed to be a risk factor for AF in men aged =65 years, 2) years of regular endurance exercise was associated with a gradually increased risk of both AF and AFL in men, 3) our study indicated that prolonged endurance exercise might be associated with AF also in women, and 4) AF was associated with poor subjective health, but the vast majority of veteran athletes engaged in regular PA and endurance exercise also after the onset of AF.
Language: English
Field: Medicine
Open Access status: green
OpenAlex ID: W2281392561
Cites: 38
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Related to: 10