Dietary Fat Intake Is Differentially Associated with Risk of Paroxysmal Compared with Sustained Atrial Fibrillation in Women.

Background: Dietary fats have effects on biological pathways that may influence the development and maintenance of atrial fibrillation (AF). However, associations between n-3 (ω-3) polyunsaturated fatty acids and AF are inconsistent, and data on other dietary fats and AF risk are sparse.

Objectives: We examined the association between dietary fatty acid (FA) subclasses and risk of incident AF and explored whether these associations differed for sustained and paroxysmal AF.

Methods: We conducted a prospective cohort study in 33,665 women ≥45 y old without cardiovascular disease (CVD) and AF at baseline in 1993. Fat intake was estimated from food frequency questionnaires at baseline and in 2004. Incident AF was confirmed by medical records through October 2013. AF patterns were classified according to the most sustained form of AF within 2 y of diagnosis. Cox proportional hazards models with the use of a competing risk model approach estimated the RR.

Results: Over 19.2 y, 1441 cases of incident AF (929 paroxysmal and 467 persistent/chronic) were confirmed. Intakes of total fat and FA subclasses were not associated with risk of AF. Saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) were differentially associated with AF patterns. The RR for a 5% increment of energy from SFAs was 1.47 (95% CI: 1.04, 2.09) for persistent/chronic and 0.85 (95% CI: 0.66, 1.08) for paroxysmal AF (P-difference = 0.01). For MUFAs, the RR for a 5% increment was 0.67 (95% CI: 0.46, 0.98) for persistent/chronic and 1.03 (95% CI: 0.78, 1.34) for paroxysmal AF, although the difference between patterns was not significant (P-difference = 0.07).

Conclusions: Dietary fat was not associated with risk of incident AF in women without established CVD or AF. High SFA and low MUFA intakes were associated with greater risk of persistent or chronic, but not paroxysmal, AF. Improving dietary fat quality may play a role in the prevention of sustained forms of AF. The Women's Health Study was registered at clinicaltrials.gov as NCT00000479.