Planetary health diet index and risk of mortality and cardiovascular disease: evidence from the health and retirement study

BACKGROUND: The EAT-Lancet Commission proposed the Planetary Health Diet to improve both human and planetary health. Evidence among older adults on its association with mortality and cardiovascular disease (CVD) remains limited. We therefore examined associations of the Planetary Health Diet Index (PHDI) with risks of all-cause mortality and CVD in a representative sample of U.S. middle-aged and older adults. METHODS: This cohort study used data from the U.S. Health and Retirement Study (HRS; 2012–2018) with dietary intake data from the 2013 Health Care and Nutrition Study (HCNS). Adherence to the PHDI was computed from 24-hour dietary recalls across 15 food groups (score range 0–140). All-cause mortality was ascertained via household surveys, and incident cardiovascular disease (CVD) was identified by self-reported physician-diagnosed heart disease. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between quintiles of PHDI and risks of mortality and CVD, adjusting for demographic, lifestyle, and health-related covariates, including total energy intake. RESULTS: The total cohort included 7,873 participants (58.83% women; mean age 66.72 years) for the mortality analysis, and the sub-cohort included 5,454 participants (60.80% women; mean age 64.65 years) for the cardiovascular disease analysis. Higher PHDI adherence was associated with lower risks of total mortality. Participants in the highest PHDI quintile had a 59% lower risk of total mortality compared with those in the lowest quintile (HRs: 0.41; 95% CI: 0.32, 0.53). Each 1 SD increase in PHDI was associated with a 25% reduction in all-cause mortality (HRs: 0.75; 95% CI: 0.69, 0.81). PHDI was also inversely associated with CVD risk (HRs: 0.72; 95% CI: 0.58, 0.91). CONCLUSIONS: In this cohort of U.S. older adults, higher adherence to the PHDI was associated with lower risks of all-cause mortality and cardiovascular disease.