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U-shaped curve revealed for association between fish consumption and atrial fibrillation

Moderation seems to be key when it comes to eating fish to prevent atrial fibrillation

Athens, Greece, 24 June 2013. Moderation seems to be key when it comes to eating fish to prevent atrial fibrillation (AF) according to an observational study presented at the EHRA EUROPACE congress held 23 to 26 June in Athens, Greece.  
Atrial Fibrillation


The study found a U-shaped association between consumption of marine n-3 polyunsaturated fatty acids (n-3 PUFA) and the risk of developing AF, with people who have both low and high intakes found to suffer more from AF than those with median intakes. The lowest risk of AF was found in those who consumed around 0.63 g marine n-3 PUFA per day, which corresponds to around two servings of fatty (oily) fish per week (1).
Earlier studies have reported that regular consumption of fish can exert beneficial effects in preventing the development of AF. Notably, in the Cardiovascular Health study (2), which included 4,815 participants, a 28% lower risk of AF was observed among people who consumed fish one to four times per week compared with those who ate fish less than once per month. However, such observed associations have not been confirmed in all cohort studies (3-8).
In the current study, Doctor Thomas Rix and colleagues from Aalborg University Hospital in Denmark, set out to examine the hypothesis that a negative association exists between the development of AF and consumption of n-3 PUFA. “Since AF is present in over six million people in Europe and associated with considerable morbidity, mortality and economic costs, preventing AF by achievable dietary changes would be of major public interest,” said Dr. Rix.

The investigators made use of the Danish Diet, Cancer and Health cohort (9), which between 1993 and 1997 enrolled a total of 57,053 Danish participants aged 50 to 64 years. The study, funded by the Danish Cancer society, had been initiated with the primary objective of exploring the role of diet in the development of cancer. Baseline data recorded for the study included a semi quantitative food frequency questionnaire with detailed questions about the consumption of fish and food products containing fish that enabled the calculation of average n-3 PUFA intakes. Levels of N-3 PUFA/day were divided into quintiles: with quintile 1 representing 0.00-0.38g marine n-3 PUFA/ day; quintile 2 representing 0.39-0.53g marine n-3 PUFA/day; quintile 3 representing 0.54 to 0.73 g marine n-3 PUFA/day; quintile 4 0.74 to 0.99 g marine n-3 PUFA/day; and quintile 5 1.00-7.22 g marine n-3 PUFA/day.
Follow-up of AF events in the population was undertaken using the Danish National Patient Registry, which recorded discharge diagnoses from hospital admissions, emergency rooms and outpatient clinics. The registry was facilitated by the Danish practice of identifying every citizen with a unique personal identification number that enables cross links to be made between different national registries.
Altogether a total of 3,425 incident cases of AF were registered during 13.6 years of follow-up. When data was analysed in a multivariate Cox regression model, in comparison to the lowest quintile a 9% lower risk of AF was seen for the second quintile (HR 0.91 95% CI 0.81-1.02); a 13 % lower risk of AF was seen for the third quintile (HR 0.87, 95% CI 0.78-0.98, p=0.02); a 4% lower rate was seen for the fourth quintile (HR 0.96, 95% CI 0.86-1.07) and a 3% increased rate was seen for the 5th quintile (HR 1.03, 95% CI 0.92-1.15).
“The 13% observed lower risk of AF seen at moderate intakes of marine n-3 PUFA compared with low intakes may be related to a reduction in ischemic heart disease and anti-inflammatory effects in addition to direct anti arrhythmic effects,” said Dr. Rix. He noted that in one study, treatment with 1.8g n-3PUFA/day in patients with low intakes of fish resulted in prolongation of the atrial effective refractory period and less inducible AF, both in subjects with AF (8) and subjects without AF (10).

“The biological mechanisms behind the higher risk of AF observed for high intakes of n-3 PUFA compared to moderate intakes were more difficult to explain,” said Dr. Rix. “We can only speculate that the balance between AF inhibiting and AF promoting effects can change according to co morbidities and intakes of marine n-3PUFA. This is the first time that such an association has been shown and it needs to be explored in further studies. However, it may help explain some of the contradictory results obtained in earlier studies.”

References

  1. TA Rix, AM Joensen, S Lundbye-Christensen et al. Moderate consumption of marine n-3 fatty acids is associated with a lower risk of atrial fibrillation – a cohort study. FP 636. Poster Session 24 June 2013. 14h00 local time.
  2. Wu JH, Lemaitre RN, King IB, Song X, Sacks FM, Rimm EB, et al. Association of plasma phospholipid long-chain omega-3 fatty acids with incident atrial fibrillation in older adults: the cardiovascular health study. Circulation 2012 Mar 6; 125(9):1084-1093.
  3. Brouwer IA, Heeringa J, Geleijnse JM, Zock PL, Witteman JC. Intake of very long-chain n-3 fatty acids from fish and incidence of atrial fibrillation. The Rotterdam Study. Am Heart J 2006 Apr; 151(4):857-862.
  4. Berry JD, Prineas RJ, van Horn L, Passman R, Larson J, Goldberger J, et al. Dietary fish intake and incident atrial fibrillation (from the Women's Health Initiative). Am J Cardiol 2010 Mar 15; 105(6):844-848.
  5. Shen J, Johnson VM, Sullivan LM, Jacques PF, Magnani JW, Lubitz SA, et al. Dietary factors and incident atrial fibrillation: the Framingham Heart Study. Am J Clin Nutr 2011 Feb; 93(2):261-266.
  6. Gronroos NN, Chamberlain AM, Folsom AR, Soliman EZ, Agarwal SK, Nettleton JA, et al. Fish, fish-derived n-3 fatty acids, and risk of incident atrial fibrillation in the Atherosclerosis Risk in Communities (ARIC) study. PLoS One 2012; 7(5):e36686.
  7. Frost L, Vestergaard P. n-3 Fatty acids consumed from fish and risk of atrial fibrillation or flutter: the Danish Diet, Cancer, and Health Study. Am J Clin Nutr 2005 Jan; 81(1):50-54.
  8. Kumar S, Sutherland F, Teh AW, Heck PM, Lee G, Garg ML, et al. Effects of chronic omega-3 polyunsaturated fatty acid supplementation on human pulmonary vein and left atrial electrophysiology in paroxysmal atrial fibrillation. Am J Cardiol 2011 Aug 15; 108(4):531-535.
  9. Tjonneland A, Olsen A, Boll K, Stripp C, Christensen J, Engholm G, et al. Study design, exposure variables, and socioeconomic determinants of participation in Diet, Cancer and Health: a population-based prospective cohort study of 57,053 men and women in Denmark. Scand J Public Health 2007; 35(4):432-441.
  10. Kumar S, Sutherland F, Rosso R, Teh AW, Lee G, Heck PM, et al. Effects of chronic omega-3 polyunsaturated fatty acid supplementation on human atrial electrophysiology. Heart Rhythm 2011 Apr; 8(4):562-568.

Scientific Programme Online

Notes to editor

About the European Society of Cardiology
The European Society of Cardiology (ESC) represents more than 80,000 cardiology professionals across Europe and the Mediterranean. Its mission is to reduce the burden of cardiovascular disease in Europe.
About the European Heart Rhythm Association
The European Heart Rhythm Association (EHRA) is a registered branch of the ESC. Its aim is to improve the quality of life of the European population by reducing the impact of cardiac arrhythmias and reducing sudden cardiac death.