Reverse association of omega-3/omega-6 polyunsaturated fatty acids ratios with carotid atherosclerosis in patients on hemodialysis

Abstract

Background and aims: Omega-3 (n-3) polyunsaturated fatty acids (PUFAs) are widely recognized to have beneficial effects against cardiovascular disease. We investigated the association of n-3 PUFAs levels with carotid atherosclerosis in patients on hemodialysis (HD), who are at high risk for cardiovascular events.

Methods: Carotid ultra-sound was performed in a total of 461 patients on HD (male 67%, age 67 ± 12years, diabetes rate 46%). Intima-media thickness (IMT) and the plaque score (PS) in carotid arteries were measured. Carotid atherosclerosis was defined as IMT >1.2 mm and/or PS > 5.0. The levels of n-6 PUFAs [dihomo-gamma-linolenic acid (DHLA) and arachidonic acid (AA)] and n-3 PUFAs [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] were also measured prior to carotid ultra-sound.

Results: Carotid atherosclerosis was observed in 94 patients (20.4%). Individual PUFAs levels were comparable between patients with and without carotid atherosclerosis. However, the ratio of EPA/AA and that of n-3/n-6 PUFAs were significantly lower in patients with carotid atherosclerosis compared to those without (median 0.36 vs. 0.41, p = 0.031 and 0.85 vs. 0.93, p = 0.041, respectively]. After adjustment for other confounders, the ratio of EPA/AA (OR 0.30, 95% CI 0.12-0.70, p = 0.0055) and the ratio of n-3/n-6 PUFAs (OR 0.45, 95% CI 0.25-0.80, p = 0.0066) showed an independent reverse association with carotid atherosclerosis. In addition, the area under receiver-operating characteristic curves for carotid atherosclerosis was significantly greater in an established risk model with EPA/AA and n-3/n-6 ratios than in the established risk model alone.

Conclusions: These data suggest that low ratios of both EPA/AA ratio and n-3/n-6 PUFAs were closely associated with carotid atherosclerosis in patients on HD.

Keywords: Atherosclerosis; Hemodialysis; Polyunsaturated fatty acids.