Healthy Eating Patterns Associated with Reduced Risk of Mortality in Large Cohort Study

Four healthy dietary patterns recommended by the Dietary Guidelines for Americans are associated with reduced risk of all-cause and cause-specific mortality, according to findings of a large prospective cohort study led by researchers at Harvard TH Chan School of Public Health.

Among the specific results reported online Jnauary 9, 2023, in JAMA Internal Medicine, greater adherence to at least one of the recommended eating plans was associated with lower risk of premature death from all causes, and from cardiovascular disease (CV), cancer, and respiratory disease. Further, the associations were consistent across racial and ethnic groups.

The Dietary Guidelines for Americans (DGAs) are published and updated every 5 years by the US Departments of Agriculture (USDA) and Health and Human Services (HHS). The DGAs are “intended to provide science-based dietary advice that promotes good health and reduces major chronic diseases,” said study investigator Frank Hu, MD, PhD, chair, department of nutrition, and Fredrick J. Stare professor of nutrition and epidemiology at the Chan School of Public Health, in a School of Public Health statement. "Thus," he added, "it is critical to examine the associations between DGA's recommended dietary patterns and long-term health outcomes, especially mortality.”

However, the authors note, there is very little research on the impact of adherence to the 4 DGA recommended healthy eating patterns on mortality leaving open to question their value as an element of public health policy meant to reduce US mortality.

To help fill this void, Hu and colleagues used health data collected over 36 years from 2 large landmark prospective cohorts, data for women coming from 75 230 participants in the Nurses’ Health Study and data for men coming from 44 085 participants in the Health Professionals Follow-up Study. The team worked with a total of more than 3.5 million person-years of follow-up data.

All participants were free of CVD or cancer at the beginning of the study and completed questionnaires on dietary habits every 4 years.

The investigators created quintiles based on dietary pattern scores for 4 healthy eating patterns recommended by the DGA: the Health Eating Index 2015(HEI-2015), Alternate Mediterranean Diet (AMED) score, Healthful Plant-based Diet Index (HPDI), and Alternate Healthy Eating Index (AHEI).

Of primary interest to Hu et al were total and cause-specific mortality for each diet overall as well as stratified by race/ethnicity and other potential risk factors.

FINDINGS

The mean age of women in the Nurse’s Health Study cohort was 50.2 years and men from the Health Professionals Follow-up Study, 53.3 years. During the total of 3 559 056 person-years of follow-up, among the total 119 315 participants there were 31 263 deaths among women and 22 900 among men.

Compared to those in the lowest quintile for each eating pattern score, a reduced risk of total mortality was observed for those with the greatest adherence to the HEI-2015 (HR, 0.81 [95% CI, 0.79-0.84]), to AMED (HR, 0.82 [95% CI, 0.79-0.84]), to HPDI (HR, 0.86 [95% CI, 0.83-0.89]), and to AHEI (HR, 0.80 [95% CI, 0.77-0.82])(P<.001 for trend for all).

The investigators found that all dietary scores were significantly inversely associated with death from CVD, cancer, and respiratory disease. When they evaluated cause-specific mortality, both the AMED score and AHEI were inversely associated with mortality from neurodegenerative disease. The reduced risk of mortality with each of the 4 dietary patterns seen in the overall population were consistent across racial and ethnic groups.

“Our findings will be valuable for the 2025-2030 Dietary Guidelines Advisory Committee, which is being formed to evaluate current evidence surrounding different eating patterns and health outcomes,” concluded authors

Reference: Shan Z, Wang F, Li Y, et al. Healthy eating patterns and risk of total and cause-specific mortality. JAMA Intern Med. Published online January 10, 2023. doi:10.1001/jamainternmed.2022.6117