Nut and Peanut Butter Consumption and Mortality in the National Institutes of Health-AARP Diet and Health Study

Although previous studies have shown inverse associations between nut consumption and mortality, the associations between nut consumption and less common causes of mortality have not been investigated. Additionally, about 50% of peanut consumption in the US is through peanut butter but the association between peanut butter consumption and mortality has not been thoroughly evaluated. The National Institutes of Health-AARP (NIH-AARP) Diet and Health Study recruited 566,398 individuals aged 50-71 at baseline in 1995-1996. A food-frequency questionnaire was used to evaluate nut and peanut butter consumption. Cox proportional hazard models were used to estimate hazard ratios and 95% confidence intervals for mortality using the non-consumers as reference groups and three categories of consumption. After excluding subjects with chronic diseases at baseline, there were 64,464 deaths with a median follow-up time of 15.5 years. We observed a significant inverse association between nut consumption and overall mortality (HR (C4 vs C1) = 0.78, 95% CI = 0.76, 0.81, p <= 0.001). Nut consumption was significantly associated with reduced risk of cancer, cardiovascular, respiratory, infectious, renal and liver disease mortality but not with diabetes or Alzheimer's disease mortality. We observed no significant associations between peanut butter consumption and all-cause (HR (C4 vs C1) = 1.00, 95% CI = 0.98, 1.04, p = 0.001) and cause-specific mortality. In a middle-aged US population, nut intake was inversely associated with all-cause mortality and certain types of cause-specific mortality. However, peanut butter consumption was not associated with differential mortality.