A systematic review and meta-analysis of nut consumption and incident risk of CVD and all-cause mortality

Dietary patterns containing nuts are associated with a lower risk of CVD mortality, and increased nut consumption has been shown to have beneficial effects on CVD risk factors including serum lipid levels. Recent studies have reported on the relationship between nut intake and CVD outcomes and mortality. Our objective was to systematically review the literature and quantify associations between nut consumption and CVD outcomes and all-cause mortality. Five electronic databases (through July 2015), previous reviews and bibliographies of qualifying articles were searched. In the twenty included prospective cohort studies (n 467 389), nut consumption was significantly associated with a lower risk of all-cause mortality (ten studies; risk ratio (RR) 0.81; 95 % CI 0.77, 0.85 for highest v. lowest quantile of intake, P-het=0.04, I-2=43 %), CVD mortality (five studies; RR 0.73; 95 % CI 0.68, 0.78; P-het=0.31, I-2=16 %), all CHD (three studies; RR 0.66; 95 % CI 0.48, 0.91; P-het=0.0002, I-2=88 %) and CHD mortality (seven studies; RR 0.70; 95 % CI 0.64, 0.76; P-het=0.65, I-2=0 %), as well as a statistically non-significant reduction in the risk of non-fatal CHD (three studies; RR 0.71; 95 % CI 0.49, 1.03; P-het=0.03, I-2=72 %) and stroke mortality (three studies; RR 0.83; 95 % CI 0.69, 1.00; P-het=0.54, I-2=0 %). No evidence of association was found for total stroke (two studies; RR 1.05; 95 % CI 0.69, 1.61; P-het=0.04, I-2=77 %). Data on total CVD and sudden cardiac death were available from one cohort study, and they were significantly inversely associated with nut consumption. In conclusion, we found that higher nut consumption is associated with a lower risk of all-cause mortality, total CVD, CVD mortality, total CHD, CHD mortality and sudden cardiac death.