Reduced CV disease and mortality with higher healthy diet score worldwide
ESC 2018 - MunichNews - Aug. 28, 2018
PURE: Prospective Urban and Rural Epidemiological
Presented at the ESC congress 2018 by: Andrew Mente (Hamilton, Canada)
Introduction and methods
High-quality diets are recommended to prevent cardiovascular (CV) disease, however, data on diets are mainly based on studies performed decades ago in high-income countries. Recent cohort studies involving all geographic regions of the world indicate that moderate intakes of whole-fat dairy, unprocessed meat, fish and nuts are protective, whereas high starches appear harmful. This study aimed to investigate the effect of quality of diet on CV risk and mortality, by developing a globally applicable diet quality tool.
The epidemiological Prospective Urban and Rural Epidemiological (PURE) cohort study included 138,527 participants (aged 35-70 years) from 50 countries without CV disease at baseline, who were divided into groups based on the quality of their diet and followed for a mean of 9.1 years. The association between diet quality, CV disease and death was first examined in the PURE data. The association was then validated in data of participants with vascular disease from the ONTARGET study and TRANSCEND study (n=31,546), and in patients with a first myocardial infarct (MI) from the INTERHEART study (n=27,098), and patients with a first stroke from the INTERSTROKE study (n=20,834).
The PURE Healthy dietary score was developed based on foods associated with lower risk of mortality in previous studies, including fruit, vegetables, nuts, legumes, fish, dairy products, and meat. Each food received a score based on quintiles of intake, with 1 for lowest quality and 5 for highest quality. Total diet score was defined as unweighted sum of each protective food, with a minimal score of 7 and maximal score of 35. CV risk and mortality in those with highest quality of diet (18 points or more) was compared to lowest quality of diet (11 points or less).
- Compared to lowest quality of diets, highest quality of diet was associated with significantly lower risks of mortality (HR: 0.75, 95%CI: 068-0.83, P-trend across diet score categories <0.001) and with a non-significant decline of major CV events (HR: 0.91, 95%CI: 0.81-1.02, P-trend across diet score categories=0.0413).
- Similar results were observed in patients with vascular diseases in ONTARGET and TRANSCEND studies. Highest quality of diet was associated with significantly lower risks of major CV events (HR: 0.86, 95%CI: 0.78-1.05, P-trend across diet score categories<0.0001), and total mortality (HR: 0.76, 95%CI: 0.68-0.84, P-trend across diet score categories <0.0001), compared to lowest quality of diet.
- In the INTERHEART and INTERSTROKE studies, highest quality of diet was significantly associated with a lower risk of MI (OR: 0.78, 95%CI: 0.71-0.85, P-trend across diet score categories<0.0001) and stroke (OR: 0.75, 95%CI: 0.68-0.84, P-trend across diet score categories <0.0001), compared to lowest quality of diet, after full adjustment.
The PURE healthy diet score compromised of higher intakes of fruit, vegs, nuts, legumes, fish, dairy and meats is associated with reduced mortality and CV disease, globally. Consistent results were obtained in four international studies, involving 218,000 people from 50 countries. Moreover, consistency was observed in patients with and without CV disease. Some elements of the PURE healthy diet score (such as dairy and meats) differ from current advice derived from earlier studies performed in high-income countries, suggesting that this advice should be reconsidered.
During the press conference it was noted that foods from the low quality quintile in this study, are typical foods recommended by the American Heart Association. This raised the question how this PURE diet can be the best diet, compared to typical recommendations. Mente explained that in high-income countries, the problem is abundance of nutrients. Diets are often high in carbohydrates, while lacking other healthy nutrients. On the other hand, low-income countries have unvaried diets leading to malnutrition. The solution for these unhealthy diets and high CV risk? A more balanced diet. Mente therefore suggests reconsideration of current advice on diets. This raised the second question whether each individual would benefit from this PURE diet. Mente answered this question by mentioning that the statistical power was not high enough to look at individual level, but we are definitely planning on assessing quality of diets in specific subgroups in order to asses how the quality of diet affects CV risk in various groups.
- Our reporting is based on the information provided at the ESC congress -