Insights from a global study: The association between dietary patterns, cardiovascular diseases, and deaths

In a recent study published in the European Heart Journal, researchers develop a healthy diet score linked to health outcomes with global applicability using the Prospective Urban Rural Epidemiology (PURE) study data.

Study: Diet, cardiovascular disease, and mortality in 80 countries. Image Credit: marilyn barbone / Shutterstock.com

Background

Unhealthy diets significantly contribute to cardiovascular disease (CVD) and mortality globally. Scores for diets such as the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and EAT-Lancet Planetary diets have been tested in Western nations. These scores combine protective and harmful foods; however, none of the scores solely focus on protective foods.

Recent research has shown that exposure to whole-fat dairy products can be protective or neutral; however, this data has yet not been added to dietary recommendations. Furthermore, it remains unclear whether inferences drawn from dietary patterns’ scores in East Asia, Europe, and the United States apply to other regions with considerable dietary variations, including Africa and South Asia.

About the study

In the present study, researchers investigate whether a healthy dietary score developed in the large global PURE study was associated with improved health outcomes worldwide. The consistency of this association across different geographies and for individuals with or without CVD was also determined.

The score for 147,642 PURE study participants residing across 21 nations was obtained. The score’s reproducibility was investigated by applying it to five large-scale study cohorts over 70 nations.

The independent studies included three studies comprising CVD patients (43,834 individuals in 50 nations) and two case-control studies of myocardial infarction (MI) (26,191 individuals in 52 nations) or stroke (26,930 individuals in 33 nations).

The three clinical trials included the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET), Telmisartan Randomized Assessment Study in ACE-Intolerant Subjects with Cardiovascular Disease (TRANSCEND), and Outcome Reduction with Initial Glargine Intervention (ORIGIN) trials. The case-control studies were the INTERHEART and INTERSTROKE studies.

The score was developed based on six foods related to significantly lowered mortality risks including vegetables, fruit, legumes, fish, nuts, and dairy. Outcome measures included major cardiovascular events such as fatal CVD, non-fatal MI, heart failure, and stroke, as well as any-cause deaths reported through July 31, 2019.

Cox frailty random effects modelling was performed to determine the relationship between dietary scores and study outcomes. The odds ratios (OR) and hazard ratios (HR) were also calculated and adjusted according to participant age, sex, education, calorie intake, physical activity, smoking status, residential location, study centers, diabetes, and the use of antihypertensive or statin medications.

A sensitivity analysis was performed by excluding probable confounding factors such as waist-to-hip ratio, body mass index, hypertension, and diabetes. The PURE healthy eating pattern comprised two to three servings of fruit and vegetables daily, three to four daily servings of legumes, seven weekly servings of nuts, two to three servings of fish weekly, and 14 weekly servings of dairy.

Individuals were recruited for the PURE study between January 1, 2003, and July 31, 2018. Physical evaluations included validated anthropometric measurements of height, weight, blood pressure, and hip and waist circumference. Dietary consumption data were obtained using nation-specific standardized food frequency questionnaires (FFQs).

Study findings

A total of 244,597 individuals were sampled from 80 nations across six continents and followed for a median of nine years, during which 15,707 deaths and 40,7674 cardiovascular events occurred. Over the nine-year follow-up period for PURE participants, as compared to scores less than one, scores exceeding five points were associated with a reduced risk of CVD, death, stroke, and MI, with HR values of 0.8, 0.7, 0.8, and 0.9, respectively.

Similar findings were reported in the three studies that included cardiovascular patients, with higher dietary scores related to lower risks of mortality, CVD, MI, and stroke, with HR values of 0.7, 0.8, 0.9, and 0.9, respectively. Likewise, in the case-control studies, higher dietary scores were related to lower rates of first stroke and MI, with OR values of 0.6 and 0.7, respectively.

Higher dietary scores were also associated with significantly lower risks of CVD or mortality in low-income nations. The PURE diet score had marginally stronger relationships with CVD or death than other dietary scores. An improvement in the diet by 20% was associated with 8% and 6% lower risks of death and CVD, respectively.

A mean value of 2.95 was observed for the PURE Healthy Dietary Score. The PURE diet score appeared to be marginally more estimative of the composite events as compared to the DASH, Mediterranean, and Healthy Eating Index (HEI)-2010 and 2015 scores and considerably more estimative when compared to the scores for the Planetary diet. These findings indicate that the ideal diet likely includes a variety of organic foods in moderate amounts instead of confining intake to a few food groups.

Conclusions

Based on the study findings, a diet consisting of higher amounts of vegetables, fruit, legumes, nuts, whole-fat dairy, and fish can reduce CVD and mortality risks globally. These observations were consistent among individuals residing in different countries throughout the world, irrespective of CVD status, particularly among those residing in low-income nations, where consumption of such foods is low.