A higher habitual flavonoid intake is associated with a lower risk of atrial fibrillation

Abstract Background Our understanding of how diet affects future risk of atrial fibrillation (AF) is limited. Evidence suggests that higher habitual intakes of flavonoids, bio-active compounds found in plant-based foods and beverages, lower cardiovascular disease risk, attenuate inflammation, and may have anti-arrhythmic properties. Purpose To investigate the association between flavonoid intake and clinically apparent AF in a large cohort of Danish men and women. Methods Baseline data from 55 634 participants without AF of the Danish Diet, Cancer and Health Study, recruited from 1993 to 1997, were cross-linked with Danish nationwide registries. Flavonoid intake was calculated from validated food frequency questionnaires using the Phenol-Explorer database. Associations between flavonoid intake and AF hospitalisation were examined using restricted cubic splines based on Cox proportional hazards models with adjustments for age, sex, BMI, smoking status, physical activity, alcohol intake, income, and hyperthyroidism. Results After a median [IQR] follow-up of 21 [18–22] years, 6 301 participants were hospitalised with AF. Non-linear associations were observed for total flavonoid intake and for all flavonoid sub-classes. For total flavonoid intake, after adjusting for potential lifestyle confounders and compared to participants in quintile 1 (median intake: 173 mg/day), those in quintile 3 (median intake: 320 mg/day) and quintile 4 (median intake: 494 mg/day) had a significantly lower risk of AF, with hazard ratios (95% CI) of 0.93 (0.87, 0.99) and 0.92 (0.86, 0.98), respectively. Compared to median intake in the lowest quintile, a total flavonoid intake of 1000 mg/day was associated with a lower risk of AF in smokers [0.86 (0.77, 0.96)] but not in non-smokers [0.96 (0.88, 1.05)], a lower risk of AF in high alcohol consumers [>20 g/d: 0.84 (0.75, 0.94)] but not in low-to-moderate alcohol consumers [<20 g/d: 0.97 (0.89, 1.06], a trending lower risk of AF in diabetics [0.76 (0.51, 1.14)] but not in non-diabetics [0.95 (0.89, 1.02)], and a trending lower risk of AF in those with ischaemic heart disease [0.84 (0.65, 1.09)] but not in those without [0.96 (0.89, 1.03), Figure 1]. Figure 1 Conclusion We observed an inverse association between total flavonoid intake and AF, most notably in sub-populations with known lifestyle and disease risk factors for AF. This finding warrants investigation in randomised controlled trials. If confirmed, ensuring the adequate consumption of flavonoid-rich foods, particularly in individuals “at risk”, may be an important strategy to mitigate AF risk. Acknowledgement/Funding The Danish Diet, Cancer, and Health Study was funded by the Danish Cancer Society.