Association of serum n-6 and n-3 polyunsaturated fatty acids with lipids in 3 populations of middle-aged men

Background: The association of serum polyunsaturated fatty acids (PUFAs) with lipids in different populations is not known. Objective: Our aim was to examine the association of serum n-6 (omega-6) or n-3 (omega-3) PUFAs with triglycerides or HDL-cholesterol concentrations in 261 white, 285 Japanese, and 212 Japanese American men aged 40-49 y. Design: We used a population-based cross-sectional study. Of the original sample (n = 926), those taking lipid-lowering medications or who had diabetes (n = 168) were excluded. Serum fatty acids were analyzed by capillary gas-liquid chromatography. Multiple regression models as a function of tertile groups of each PUFA were used. Results: Serum n = 6 PUFAs were significantly inversely associated with triglycerides across populations after adjustment for age, body mass index, pack-years of smoking, and ethanol consumption [β = -0.39 (P < 0.001), -0.38 (P < 0.001), and -0.33 (P < 0.001) in whites, Japanese, and Japanese Americans, respectively]. Marine n-3 PUFAs were significantly inversely associated with triglycerides across populations [β = -0.15 (P < 0.001), -0.22 (P < 0.001), and -0.13 (P < 0.001) in whites, Japanese, and Japanese Americans, respectively]. n-6 PUFAs were significantly positively associated with HDL cholesterol in whites (β = 4.49, P < 0.001) and Japanese (β = 3.73, P < 0.01). Marine n-3 PUFAs were significantly positively associated with HDL cholesterol in Japanese (β = 2.15, P < 0.05), and eicosapentaenoic acid was significantly positively associated with HDL cholesterol in whites (β = 2.68, P < 0.01). Conclusion: Serum n-6 and n-3 PUFAs are inversely associated with triglycerides across populations.