Relationship of tree nut, peanut and peanut butter intake with total and cause-specific mortality: A cohort study and meta-analysis

Abstract

Background: Nut intake has been associated with lower mortality, but few studies have investigated causes of death other than cardiovascular disease, and dose-response relationships remain unclear. Methods: We investigated the relationship of nut (tree nut, peanut) and peanut butter intake with overall and cause-specific mortality. In the Netherlands Cohort Study, 120 852 men and women aged 55-69 years provided information on dietary and lifestyle habits in 1986. Mortality follow-up until 1996 consisted of linkage to Statistics Netherlands. Multivariate case-cohort analyses were based on 8823 deaths and 3202 subcohort members with complete data on nuts and potential confounders. We also conducted metaanalyses of our results with those published from other cohort studies. Results: Total nut intake was related to lower overall and cause-specific mortality (cancer, diabetes, cardiovascular, respiratory, neurodegenerative diseases, other causes) in men and women. When comparing those consuming 0.1-<5, 5-<10 and 10+g nuts/day with non-consumers, multivariable hazard ratios for total mortality were 0.88, 0.74 and 0.77 [95% confidence interval (CI), 0.66-0.89], respectively (Ptrend=0.003). Cause-specific hazard ratios comparing 10+ vs 0 g/day varied from 0.56 for neurodegenerative to 0.83 for cardiovascular disease mortality. Restricted cubic splines showed nonlinear doseresponse relationships withmortality. Peanuts and tree nuts were inversely related tomortality, whereas peanut butter was not. Inmeta-analyses, summary hazard ratios for highest vs lowest nut consumption were 0.85 for cancer, and 0.71 for respiratory mortality. Conclusions: Nut intake was related to lower overall and cause-specific mortality, with evidence for nonlinear dose-response relationships. Peanut butter was not related to mortality.