Abstract P663: Significantly Slower Progression of Aortic Calcification Among Japanese in Japan Than White and Japanese Americans in a Multiethnic Cohort of Middle-Aged Men - ERA JUMP (Electron-Beam Computed Tomography and Risk Factor Assessment in Japanese and US Men in the Post-World War II Birth Cohort) Study

Background: Calcification of the aorta is a biomarker of atherosclerosis and a predictor of cardiovascular morbidity and mortality. Low mortality from coronary heart disease in Japan cannot be fully explained by genetics or traditional risk factors. Our objective was to compare the progression of aortic calcification (AC) between Japanese in Japan, white Americans, and third-generation Japanese Americans without ethnic admixture in population-based samples of middle-aged men from the ERA JUMP cohort and to examine whether the higher blood levels of marine omega–3 fatty acids (OM3) in Japanese in Japan than in Americans account for the difference. Method: Men (n=700) aged 40-49 years (252 Japanese in Japan, 238 white Americans, and 210 Japanese Americans) were examined at baseline and 4-7 years later. AC was evaluated from the aortic arch to the iliac bifurcation with computed tomography. AC score was assessed with the Agatston method. Progression of AC score was calculated as the difference between the follow-up and baseline of the natural log-transformed AC+1. Robust linear regression models were used to compare the progression of AC and multivariable logistic regression models were fitted to compare the incidence of AC (AC≥50 at follow-up) among those with baseline AC<50. Results: Japanese in Japan had a significantly slower progression and lower incidence of AC compared to white and Japanese Americans after adjusting for age, baseline AC score, follow-up time, and traditional risk factors. Median blood levels of OM3 were 7.9% for Japanese in Japan, 2.6% for white Americans and 3.8% for Japanese Americans. Additional adjustment for OM3 did not account for the significant difference in AC progression but accounted for the difference in incidence between Japanese in Japan and Japanese Americans (Table 1). Conclusion: Japanese in Japan had a significantly slower progression and lower incidence of AC compared to white and Japanese Americans. Higher OM3 in Japanese in Japan partly accounted for the difference in incidence.