Background: Previous studies have reported beneficial effects of a Mediterranean diet rich in monounsaturated fatty acids (MUFAs) on coronary artery disease (CAD) risk. However, these findings remain inconsistent because some experimental studies have suggested atherogenic and lipotoxicity effects of long-chain and very-long-chain MUFAs on cardiomyocytes.
Objective: We examined whether red blood cell (RBC) long-chain and very-long-chain MUFAs are associated with risk of CAD in the Physicians' Health Study.
Design: The ancillary study used a prospective nested case-control design to select 1000 cases of incident CAD and 1000 control subjects matched for age, year of birth, and time of blood collection. RBC MUFAs were measured by using gas chromatography, and CAD was validated by an endpoint committee. Conditional logistic regression was used to estimate RRs.
Results: The mean (±SD) age was 68.7 ± 8.7 y. In a multivariable model that was controlled for matching factors and established CAD risk factors and RBC saturated and omega-3 (n-3) fatty acids, ORs for CAD associated with each SD increase of 20:1n-9 and log 22:1n-9 were 0.89 (95% CI: 0.80, 1.00; P = 0.0441) and 0.83 (95% CI: 0.72, 0.95; P = 0.0086). However, only the 22:1n-9-CAD relation remained statistically significant after Bonferroni correction (P < 0.0125). RBC cis 18:1n-9 and 24:1n-9 were not associated with CAD risk.
Conclusion: Our data suggest an inverse association of RBC 22:1n-9 but not 20:1n-9, 18:1n-9, or 24:1n-9 with CAD risk after Bonferroni correction in the Physicians' Health Study.