Acidi grassi omega 3 e mortalità cardiaca

Kromhout D, Giltay EJ, Geleijnse JM; Alpha Omega Trial Group.
N Engl J Med. 2010 Nov 18;363(21):2015-26.

08-12-2010

Il consumo moderato di acidi grassi omega 3 o n-3 si associa alla riduzione della mortalità cardiovascolare, in parte attraverso un’azione antiaritmogena.
In questo studio multicentrico controllato (Alpha Omega Trial) sono stati valutati gli effetti dell’assunzione di acido eicosapentaenoico (EPA) e docosaesaenoico (DHA) contenuti nel pesce e dell’acido alfa linolenico (ALA), di origine vegetale, sulla frequenza degli eventi cardiovascolari in 4837 pazienti con pregresso infarto miocardico, di età compresa tra 60 e 80 anni, prevalentemente di sesso maschile (78%), sottoposti ad adeguato trattamento farmacologico antiipertensivo, antitrombotico e ipolipemizzante. I pazienti sono stati assegnati in modo randomizzato a gruppi diversi per tipologia di margarina consumata per 40 giorni: standard, con EPA + DHA (400 mg/die, EPA/DHA=1,5/1) con ALA (2 g/die) oppure con EPA+DHA+ALA. Dall’analisi statistica non sono emerse differenze tra i gruppi di pazienti né per quanto riguarda la frequenza degli eventi cardiovascolari né per quanto riguarda gli effetti indesiderati. Una tendenza alla protezione dagli eventi cardiovascolari vicina alla significatività è stata riscontrata nella popolazione femminile sottoposta a trattamento con ALA (HR 0.73, P=0.07).
La supplementazione della dieta con dosi moderate di acidi grassi n-3 non modifica il rischio cardiovascolare in soggetti con pregresso infarto del miocardio, sottoposti ad adeguata terapia farmacologica.

Glossario

  • Supplementazione

    Se i soggetti trattati sono ignari del fatto di aver ricevuto l'uno o l'altro dei trattamento testati, lo studio si definisce "in cieco". Se anche lo sperimentatore lo è, almeno fino al termine della raccolta dati, lo studio si definisce "in doppio cieco".

n-3 fatty acids and cardiovascular events after myocardial infarction.

BACKGROUND: Results from prospective cohort studies and randomized, controlled trials have provided evidence of a protective effect of n-3 fatty acids against cardiovascular diseases. We examined the effect of the marine n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and of the plant-derived alpha-linolenic acid (ALA) on the rate of cardiovascular events among patients who have had a myocardial infarction.
METHODS: In a multicenter, double-blind, placebo-controlled trial, we randomly assigned 4837 patients, 60 through 80 years of age (78% men), who had had a myocardial infarction and were receiving state-of-the-art antihypertensive, antithrombotic, and lipid-modifying therapy to receive for 40 months one of four trial margarines: a margarine supplemented with a combination of EPA and DHA (with a targeted additional daily intake of 400 mg of EPA-DHA), a margarine supplemented with ALA (with a targeted additional daily intake of 2 g of ALA), a margarine supplemented with EPA-DHA and ALA, or a placebo margarine. The primary end point was the rate of major cardiovascular events, which comprised fatal and nonfatal cardiovascular events and cardiac interventions. Data were analyzed according to the intention-to-treat principle, with the use of Cox proportional-hazards models.
RESULTS: The patients consumed, on average, 18.8 g of margarine per day, which resulted in additional intakes of 226 mg of EPA combined with 150 mg of DHA, 1.9 g of ALA, or both, in the active-treatment groups. During the follow-up period, a major cardiovascular event occurred in 671 patients (13.9%). Neither EPA-DHA nor ALA reduced this primary end point (hazard ratio with EPA-DHA, 1.01; 95% confidence interval [CI], 0.87 to 1.17; P=0.93; hazard ratio with ALA, 0.91; 95% CI, 0.78 to 1.05; P=0.20). In the prespecified subgroup of women, ALA, as compared with placebo and EPA-DHA alone, was associated with a reduction in the rate of major cardiovascular events that approached significance (hazard ratio, 0.73; 95% CI, 0.51 to 1.03; P=0.07). The rate of adverse events did not differ significantly among the study groups.
CONCLUSIONS: Low-dose supplementation with EPA-DHA or ALA did not significantly reduce the rate of major cardiovascular events among patients who had had a myocardial infarction and who were receiving state-of-the-art antihypertensive, antithrombotic, and lipid-modifying therapy.

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