Association of Nut Consumption and Mortality | Journal Scan

Study Questions:

Is nut consumption associated with reduced total and cause-specific mortality?

Methods:

Three large cohorts were used to examine nut consumption in association with mortality. A total of 71,764 Americans of African and European descent who enrolled in the Southern Community Cohort Study were included in the US cohort. This study included subjects primarily of low socioeconomic status residing in the southeastern United States from March 2002 to September 2009. The other two cohorts included women residing in Shanghai, China, who were enrolled in the Shanghai Women’s Health Study from December 1996 to May 2000, and men who were enrolled in the Shanghai Men’s Health Study from January 2002 to September 2006. Self-reported nut consumption was the exposure of interest. The primary outcome of interest was mortality assessed through the National Death Index and Social Security Administration Mortality files for the US participants, and the Shanghai Vital Statistics Registry and home visits for the two Shanghai cohorts.

Results:

Over a median follow-up of 5.4 years, 6,256 deaths occurred in the US cohort. Over a median follow-up of 6.5 years in the Shanghai men’s cohort, 3,387 deaths occurred, and in the Shanghai women, 4,757 deaths occurred over a median follow-up of 12.2 years. Women in the US cohort were more likely to report ever smoking compared to the Shanghai women, while smoking was highly prevalent in both the US and China men. Consumption of nuts was inversely associated with all-cause mortality in all three cohorts (p < 0.001). Comparing the highest and lowest quintiles of nut intake, the hazard ratio (HR) was 0.79 (95% confidence interval [CI], 0.73-0.86) for the US cohort and 0.83 (95% CI, 0.77-0.88) for the Shanghai cohorts after adjustment for multiple potential confounders. Those who reported the highest intake of nuts had the lowest rate of ischemic heart disease (HR, 0.62; 95% CI, 0.45-0.85 in blacks; HR, 0.60; 95% CI, 0.39-0.92 in whites; and HR, 0.70; 95% CI, 0.54-0.89 in Asians) compared to those who reported the lowest intake of nuts. Similar associations were noted for ischemic stroke and hemorrhagic stroke, but were statistically significant only in the Asian cohorts. Risk reduction associated with nut consumption was similar for men and women in both cohorts.

Conclusions:

The investigators concluded that nut consumption was associated with a reduction in overall mortality and cardiovascular mortality. They also concluded that peanut consumption may be a cost-effective food, which can improve cardiovascular health.

Perspective:

These data support the importance of a healthy diet for cardiovascular risk reduction, in particular, addition of nuts to the diet. Further research to examine the contribution of healthy oils compared to fiber or other components of nuts in relation to cardiovascular health is warranted.

Keywords: Nuts, Diet, Oils, Smoking, Cardiovascular Diseases, Myocardial Ischemia, Stroke, Secondary Prevention, Cohort Studies, China, Men's Health, Women's Health, Risk Factors, Risk Reduction Behavior, Self Report, Social Class


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