Healthy Diet Aids Survival After Myocardial Infarction
http://www.medpagetoday.com/Cardiology/MyocardialInfarction/41379
Published: Sep 4, 2013 | Updated: Sep 5, 2013
By Crystal Phend, Senior Staff Writer, MedPage Today
The same heart-healthy diet that can prevent heart disease also might boost survival long-term after a heart attack, observational results indicated.
Overall, the healthiest eaters were 24% less likely to die during the study period after initially surviving a myocardial infarction (MI) than those who had the worst diets, Shanshan Li, MD, MSc, ScD, of the Harvard School of Public Health, and colleagues found.
People who improved their diet the most after an MI also had a 29% lower overall and 40% lower cardiovascular mortality risk compared with those who changed the least, the researchers reported online in JAMA Internal Medicine.
That’s an effect “as powerful as the effect of statins, without the adverse effects or costs,” noted an accompanying invited commentary by Ramón Estruch, MD, PhD, of the University of Barcelona, and Emilio Ros, MD, PhD, of the Hospital Clinic in Barcelona.
Diet quality in Li’s analysis of the Nurses’ Health Study and the Health Professionals Follow-up Study was defined by components linked to coronary heart disease risk in primary prevention studies:
Vegetables
Fruit
Nuts and legumes
Red and processed meats
Sugar-sweetened drinks
Alcohol
Polyunsaturated fat
Trans fat
Omega 3 fats
Whole grain
Sodium intake
This model shares a lot in common with the Mediterranean diet, which has been linked to primary cardiovascular prevention in the PREDIMED trial and secondary prevention in the Lyon Diet Heart Study, the commentators pointed out.
Further clinical trials would be nice to refine the advice to patients on the best diet for their heart and longevity, but in the meantime the scientific evidence is compelling to promote better dietary choices, they concluded.
The analysis included all 2,258 women from the Nurses’ Health Study and 1,840 men from the Health Professionals Follow-up Study who initially survived an MI during follow-up and had data from food frequency questionnaires before and after. The investigators defined the post-MI period as the time from the return of the first post-MI food questionnaire until death or the end of the study period (June 30, 2008).
Diet quality was measured using the Alternative Healthy Eating Index 2010, which summed scores for each of the 11 components as mentioned above on a 10-point scale from best to worst into a 110-point total adherence score.
The score “has the specific components more relevant to Western diets, such as trans fat, sugar-sweetened beverages, and red and processed meat,” compared with Mediterranean diet adherence scales, the researchers pointed out.
Most of the participants improved their diet after a heart attack, with median changes of 5.5 points among men and 2.1 points among women.
They did this largely by boosting whole grain intake and cutting trans fats and red and processed meat consumption. Sugary drink habits showed the least change.
After adjustment for medication use, medical history, and lifestyle risk factors, the top quintile for post-MI diet had a pooled hazard ratio of 0.76 (95% confidence interval 0.60-0.96) for death from any cause during post-MI follow-up compared with the bottom quintile.
That effect was almost entirely accounted for by women, without a significant association among men.
The researchers suggested this unexpected sex difference could have been due to the limited number of events in the extreme categories for diet among men or due to greater case fatality among women, differences in MI development and progression, initial MI management, or other factors.
For cardiovascular mortality, the pooled results showed a similar hazard ratio of 0.73 for the healthiest versus poorest diet quintiles that wasn’t significant overall (95% CI 0.51-1.04) but was for women (P=0.03 for trend).
Individuals in the top quintile for increase in their healthy diet score from before to after their MI had an adjusted hazard ratio of 0.71 for all-cause mortality (95%CI 0.56-0.91) and 0.60 for cardiovascular mortality (95%CI 0.41-0.86) compared with those who improved the least.
In a sensitivity analysis excluding alcohol intake as a component of a heart-healthy diet, the results were similar.
Further adjustment for beta-blocker use, anti-hypertensive medication, and clinical characteristics didn’t have much impact either. Statins, aspirin, and age at MI didn’t interact with the diet associations.
Limitations included the possibility of residual confounding, potential lack of generalizability from the predominantly white doctors and nurses included in the study, and self-reported diet.
“Further studies on the effects of dietary changes from pre- to post-MI are needed because of the direct clinical relevance of our findings. Dietary recommendations for secondary prevention need to place more emphasis on polyunsaturated fat intake and reduced consumption of sugar-sweetened beverages and fruit juice,” the authors concluded.
The study was supported by grants from the National Institutes of Health.
The researchers and commentators reported having no conflicts of interest to disclose.
Primary source: JAMA Internal Medicine
Source reference: Li S, et al “Better diet quality and decreased mortality among myocardial infarction survivors” JAMA Intern Med 2013; DOI: 10.1001/jamainternmed.2013.9768.
http://archinte.jamanetwork.com/article.aspx?articleid=1733453
Additional source: JAMA Internal Medicine
Source reference:Estruch R, Ros E “Eat a healthy diet and drink wisely to postpone dying if you survived a myocardial infarction? Yes, but randomized clinical trials are needed” JAMA Intern Med 2013; DOI: 10.1001/jamainternmed.2013.7667.
http://archinte.jamanetwork.com/article.aspx?articleid=1733446