Abstract 2770: Difference in Serum Levels of Docosahexaenoic Acid (DHA) May Explain the Difference in Carotid Intima-Media Thickness Between US White and Japanese Men Aged 40–49
Background and Purpose: Low coronary heart disease (CHD) mortality in the Japanese in Japan is very unique. We previously reported that carotid intima-media thickness (IMT) in men aged 40 – 49 was significantly higher in US whites than in the Japanese; the difference remained after adjusting for traditional and other various risk factors. We tested the hypothesis that serum levels of n3 fatty acids explain the difference in IMT in men aged 40 – 49 between US whites and the Japanese in Japan.
Methods: We examined 558 randomly selected men aged 40 – 49 from population-based samples: 258 US whites and 300 Japanese in Japan. Exclusion criteria included those with clinical cardiovascular disease and on lipid medications. We have standardized methods including imaging and reading IMT.
Results: US whites as compared to the Japanese had a more favorable or similar profile of many risk factors including blood pressure (BP), total cholesterol, LDL-C, triglycerides (TG), smoking, and fasting glucose. Exceptions included obesity and HDL-C. Serum percentages of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), major n3 fatty acids found in fish, were significantly lower in US whites than the Japanese in Japan: 0.76±0.61 vs. 2.49 ±1.38 respectively for EPA (P<0.01) and 2.63±1.30 vs. 6.26±1.67, respectively for DHA (P<0.01). Carotid IMT was significantly higher in US whites than the Japanese in Japan. The difference remained after adjusting for age, BMI, BP, LDL-C, TG, HDL-C, and smoking (Table⇓). In both populations, serum levels of DHA were inversely associated with carotid IMT, although the associations were not significant. The difference in carotid IMT between US whites and the Japanese was attenuated after adjusting for DHA (Table⇓). DHA itself was associated with carotid IMT independent of other risk factors.
Conclusion: The results suggest that DHA may have a strong anti-atherogenic effect.