Association of Walnut Consumption with Total and Cause-Specific Mortality and Life Expectancy in U.S. Women and Men

Abstract

Abstract Objectives We aim to 1) examine the association between walnut consumption and subsequent total and cause-specific mortality; 2) to estimate life expectancy that would be potentially gained by varying intake of walnuts in U.S. women and men. Methods Walnut consumption was assessed using validated food frequency questionnaires in 1998 (baseline year) and updated every 4 years. We included data from 68,308 women of the Nurses’ Health Study (1998–2016) and 26,760 men of the Health Professionals Follow-up Study (1998–2016) who were free of cancer, heart disease, and stroke at baseline. We used Cox regression models adjusting for confounders to estimate mortality risk associated with walnut consumption stratified by sex and dietary quality. We used population based multistate life tables to calculate the differences in life expectancy and years lived in relation to walnut consumption. Results During up to 18 years of follow-up, we documented 30,502 deaths from any cause. The multivariable-adjusted hazard ratios (HRs) for total mortality across categories of walnut intake (servings/week), as compared to non-consumers, were 0.91 (95% confidence interval [CI], 0.89–0.94), for <1 serving/week, 0.87 (95% CI, 0.83–0.92) for 1 serving/week, 0.79 (95% CI, 0.75–0.85), for 2–4 servings/week, and 0.77 (95% CI,: 0.71–0.81) for >= 5 servings/week (P for trend <0.0001). Per 0.5 serving/day walnut consumption was associated of a reduced risk of total mortality (HR: 0.82, 95% CI,: 0.77–0.88), CVD mortality (HR: 0.78, 95% CI,: 0.67–0.33), and cancer mortality (HR: 0.93, 95% CI:, 0.81–1.07) in participants with a suboptimal diet (AHEI score <60% of cohort distribution). A greater life expectancy of 1.78 years in women and 1.94 years in men was observed among those who consumed walnuts more than 5 servings/week, compared to non-consumers at age 60. Conclusions Higher walnut consumption was associated with lower risk for total mortality and longer estimated life expectancy among U.S. men and women of two prospective cohort studies. Our results provide evidence on the potential role of walnut in the prevention of premature death. Funding Sources UM1 CA186107, UM1 CA176726, UM1 CA167552 Y.L. was partly funded by the California Walnut Commission. The funders have no roles in the design and conduct of the study.