Nut consumption and 5-y all-cause mortality in a Mediterranean cohort: The SUN project

ObjectiveThe aim of this study was to assess the association between nut consumption and all-cause mortality after 5-y follow-up in a Spanish cohort.MethodsThe SUN (Seguimiento Universidad de Navarra, University of Navarra Follow-up) project is a prospective cohort study, formed by Spanish university graduates. Information is gathered by mailed questionnaires collected biennially. In all, 17 184 participants were followed for up to 5 y. Baseline nut consumption was collected by self-reported data, using a validated 136-item semi-quantitative food frequency questionnaire. Information on mortality was collected by permanent contact with the SUN participants and their families, postal authorities, and the National Death Index. The association between baseline nut consumption and all-cause mortality was assessed using Cox proportional hazards models to adjust for potential confounding. Baseline nut consumption was categorized in two ways. In a first analysis energy-adjusted quintiles of nut consumption (measured in g/d) were used. To adjust for total energy intake the residuals method was used. In a second analysis, participants were categorized into four groups according to pre-established categories of nut consumption (servings/d or servings/wk). Both analyses were adjusted for potential confounding factors.ResultsParticipants who consumed nuts ≥2/wk had a 56% lower risk for all-cause mortality than those who never or almost never consumed nuts (adjusted hazard ratio, 0.44; 95% confidence intervals, 0.23–0.86).ConclusionNut consumption was significantly associated with a reduced risk for all-cause mortality after the first 5 y of follow-up in the SUN project.