Objective To examine the association between risk factor burdens—categorized as optimal, borderline, or elevated—and the lifetime risk of atrial fibrillation. Design Community based cohort study. Setting Longitudinal data from the Framingham Heart Study. Participants Individuals free of atrial fibrillation at index ages 55, 65, and 75 years were assessed. Smoking, alcohol consumption, body mass index, blood pressure, diabetes, and history of heart failure or myocardial infarction were assessed as being optimal (that is, all risk factors were optimal), borderline (presence of borderline risk factors and absence of any elevated risk factor), or elevated (presence of at least one elevated risk factor) at index age. Main outcome measure Lifetime risk of atrial fibrillation at index age up to 95 years, accounting for the competing risk of death. Results At index age 55 years, the study sample comprised 5338 participants (2531 (47.4%) men). In this group, 247 (4.6%) had an optimal risk profile, 1415 (26.5%) had a borderline risk profile, and 3676 (68.9%) an elevated risk profile. The prevalence of elevated risk factors increased gradually when the index ages rose. For index age of 55 years, the lifetime risk of atrial fibrillation was 37.0% (95% confidence interval 34.3% to 39.6%). The lifetime risk of atrial fibrillation was 23.4% (12.8% to 34.5%) with an optimal risk profile, 33.4% (27.9% to 38.9%) with a borderline risk profile, and 38.4% (35.5% to 41.4%) with an elevated risk profile. Overall, participants with at least one elevated risk factor were associated with at least 37.8% lifetime risk of atrial fibrillation. The gradient in lifetime risk across risk factor burden was similar at index ages 65 and 75 years. Conclusions Regardless of index ages at 55, 65, or 75 years, an optimal risk factor profile was associated with a lifetime risk of atrial fibrillation of about one in five; this risk rose to more than one in three in individuals with at least one elevated risk factor.

Atrial fibrillation is associated with increased cardiovascular morbidity and mortality.^1-4 The risk of atrial fibrillation increases exponentially with age, and it has been estimated that the prevalence of atrial fibrillation after the age of 75 years is 7% to 8% in men and 2% to 6% in women.^5,6 The most important risk factors for atrial fibrillation are increasing age, male sex, hypertension, diabetes, myocardial infarction, and congestive heart failure.⁷

Evidence for an association between alcohol consumption and risk of atrial fibrillation is conflicting. Cohort studies such as the Framingham Heart Study,¹ the Manitoba Follow-up Study,² the Multifactor Primary Prevention Study,³ and the Renfrew/Paisley Study⁴ did not find any association between alcohol consumption and risk of atrial fibrillation. However, the Cardiovascular Health Study⁵ reported that alcohol consumption reduced the risk of atrial fibrillation in a dose-response–related manner. A recently published case-control study reported an adjusted relative risk of 2.4 (95% confidence interval, 1.4-4.1) for atrial fibrillation among subjects who consumed more than 42 units (>420 g) of alcohol per week.⁶ None of these studies reported on drinking pattern or source of alcohol and risk of atrial fibrillation. We did a prospective follow-up investigation in the Danish Diet, Cancer, and Health Study cohort to further assess the potentials of hazard of atrial fibrillation or flutter associated with alcohol consumption. We examined the risk of atrial fibrillation or flutter related to the amount of daily alcohol consumption, frequency of alcohol consumption, and the type of alcohol consumed (wine vs beer) in men and women.

Background: Experimental studies have shown that n−3 polyunsaturated fatty acids in fish may have antiarrhythmic properties. Objective: We examined the association between consumption of n−3 fatty acids from fish and risk of atrial fibrillation or flutter. Design: In a prospective cohort study of 47 949 participants (mean age: 56 y) in the Danish Diet, Cancer, and Health Study, we investigated the relation between the consumption of n−3 fatty acids from fish estimated from a detailed semiquantitative food questionnaire and risk of atrial fibrillation or flutter. The subjects were followed up in the Danish National Registry of Patients for the occurrence of atrial fibrillation or flutter and in the Danish Civil Registration System (vital status and emigration). The consumption of n−3 fatty acids from fish was analyzed as sex-specific quintiles with the use of Cox proportional hazards models. Results: During follow-up (x̄: 5.7 y), atrial fibrillation or flutter had developed in 556 subjects (374 men and 182 women). When the lowest quintile of n−3 fatty acids consumed from fish was used as a reference, the unadjusted hazard rate ratios in quintiles 2, 3, 4, and 5 were 0.93, 1.11, 1.10, and 1.44, respectively (P for trend = 0.001). The corresponding adjusted hazard rate ratios were 0.86, 1.08, 1.01, and 1.34 (P for trend = 0.006). Inclusion of information on the frequency of fatty fish consumption did not alter these associations. Conclusions: Consumption of n−3 fatty acids from fish was not associated with a reduction in risk of atrial fibrillation or flutter. We cannot exclude the possibility of residual confounding caused by a lack of information on intake of fish-oil tablets.

Objectives: To examine how the lifetime risks of atrial fibrillation and of complications after atrial fibrillation changed over time. Design: Danish, nationwide, population based cohort study. Setting: Population of Denmark from 1 January 2000 to 31 December 2022. Participants: 3.5 million individuals (51.7% women and 48.3% men) who did not have atrial fibrillation at 45 years of age or older were followed up until incident atrial fibrillation, migration, death, or end of follow-up, whichever came first. All 362 721 individuals with incident atrial fibrillation (46.4% women and 53.6% men), but with no prevalent complication, were further followed up until incident heart failure, stroke, or myocardial infarction. Main outcome measures: Lifetime risk of atrial fibrillation and lifetime risks of complications after atrial fibrillation over two prespecified periods (2000-10 v 2011-22). Results: The lifetime risk of atrial fibrillation increased from 24.2% in 2000-10 to 30.9% in 2011-22 (difference 6.7% (95% confidence interval 6.5% to 6.8%)). After atrial fibrillation, the most frequent complication was heart failure with a lifetime risk of 42.9% in 2000-10 and 42.1% in 2011-22 (−0.8% (−3.8% to 2.2%)). Individuals with atrial fibrillation lost 14.4 years with no heart failure. The lifetime risks of stroke and of myocardial infarction after atrial fibrillation decreased slightly between the two periods, from 22.4% to 19.9% for stroke (−2.5% (−4.2% to −0.7%)) and from 13.7% to 9.8% for myocardial infarction (−3.9% (−5.3% to −2.4%). No evidence was reported of a differential decrease between men and women. Conclusion: Lifetime risk of atrial fibrillation increased over two decades of follow-up. In individuals with atrial fibrillation, about two in five developed heart failure and one in five had a stroke over their remaining lifetime after atrial fibrillation diagnosis, with no or only small improvement over time. Stroke risks and heart failure prevention strategies are needed for people with atrial fibrillation.