Scientific Study

Background: The link between nut consumption and cardiovascular (CV) mortality remains unclear.

Objective: to examine whether nut consumption is associated with CV mortality and estimate the proportion of reduced risk of CV mortality explained by intermediate factors.

Methods: We studied 39,167 women from the Women's Health Study; 28,034 provided blood samples. Nut consumption was self-reported at baseline and at follow-up using a food frequency questionnaire. Our primary outcome was cardiovascular death, which was ascertained via medical records, confirmed with the national death index and death certificates.

Results: During a mean follow-up of 19 years, 959 CV deaths occurred. In a multivariable Cox regression model adjusting for age, body mass index, smoking, alcohol use, physical activity, postmenopausal status, marital status, family history of premature myocardial infarction and the alternate healthy eating index score, hazard ratios for CV mortality were 0.93 (0.76-1.14) for nut consumption of 1-3 times/month, 0.84 (0.69-1.01) for nut intake of 1 time/week, and 0.73 (0.61-0.87) for nut consumption of ≥2 times/week when compared to women who did not consume nuts (p = 0.0004). LDL and total cholesterol accounted for about 19%, HbA1c 18% and all mediating factors together accounted for about 6.6% of the lower risk of CV mortality for those who consumed nuts ≥2 times/week. For the secondary outcome of CV events, although the effect was noted to be in the same direction with increasing nut consumption associated with lower risk of CV events, it was not statistically significant (p = 0.07).

Conclusion: This study suggests that nut consumption is inversely associated with cardiovascular mortality in women. Lipids, inflammatory markers and glucose metabolism account for a modest proportion of the lowered CV mortality observed with nut consumption, assuming a causal nut-CV mortality association.