Associations between White Meat-Only and Vegetarian Diets with Mortality from All Causes, Heart Diseases, Cancers, and Stroke in the American Cancer Society's Cancer Prevention Study-II.

BACKGROUND: Many dietary guidelines recommend limiting or excluding red and processed meat to promote health and prevent chronic diseases. OBJECTIVES: This study investigated associations between white meat-only and vegetarian diets and mortality from all causes, heart diseases, cancers, and stroke. METHODS: The American Cancer Society's Cancer Prevention Study-II (CPS-II) cohort participants aged 30 to 95 y at baseline (1982) with mortality data through 2020 were examined (n = 998,378; 45% male, n = 626,017 deaths). A brief diet questionnaire identified meat intake [red/processed meat intake: high (≥6 d/wk); moderate (4 to <6 d/wk); low (0.5 to <4 d/wk); white meat-only; vegetarian]. Cox proportional hazards models adjusted for demographic, lifestyle, and health factors examined associations between diet categories and mortality risk. Effect modification by sex, smoking, BMI, baseline age group, and attained age was examined. RESULTS: Most participants consumed red/processed meat (high = 37%, moderate = 31%, low = 31%; white meat-only = 1%; vegetarian = 0.4%). Compared with high red/processed meat intake, low intake was associated with 1% to 5% lower mortality risk from all causes, heart diseases, and cancers across multiple strata, and 4% lower stroke mortality risk overall [hazard ratio (HR): 0.96; 95% confidence interval (CI): 0.94, 0.99]. White meat-only was associated with 5% to 7% lower all-cause mortality risk among males (HR: 0.93; 95% CI: 0.89, 0.98), individuals with healthy weight (HR: 0.95; 95% CI: 0.91, 0.98), and the 50 to 64 y age group (HR: 0.94; 95% CI: 0.90, 0.97), where results were similar with a vegetarian diet (50-64 y; HR: 0.94; 95% CI: 0.88, 1.00). Among participants reaching age ≥80, white meat-only was associated with lower all-cause (HR: 0.94; 95% CI: 0.91, 0.97) and cancer mortality risk (HR: 0.91; 95% CI: 0.83, 0.99). No other associations were statistically significant. CONCLUSIONS: In CPS-II, limiting red/processed meat intake was associated with a small but significantly lower risk of all-cause and cause-specific mortality. Diets excluding red/processed meat may lower risk in certain subgroups, but large studies targeting these diets are needed to elucidate associations with mortality.