This dissertation includes three manuscripts focusing on health disparities between whites and Japanese with regard to measures of diabetes and subclinical atherosclerosis in the EBCT and Risk Factor Assessment among Japanese and U.S. Men in the Post World War II Birth Cohort (ERA JUMP) study. The first manuscript compares markers of insulin resistance and insulin secretion between white men in the United States and Japanese men in Japan, adjusting for visceral adipose tissue and other covariates. Whites had significantly higher HOMA-IR, HOMA-β%, and disposition index (DI) than Japanese in Japan. The better compensation of insulin resistance by increased insulin secretion in whites as shown by higher DI may partly explain lower susceptibility of whites to developing type 2 diabetes than Japanese in Japan at similar levels of body-mass index.The second manuscript compares progression of intima-media thickness of the carotid artery (CIMT) between middle-aged Japanese American men and white men, adjusting for baseline cardiovascular risk factors. Japanese Americans had greater progression of CIMT than whites. The third manuscript compares progression of coronary artery calcium (CAC) between Japanese American men and white men. Japanese Americans had similar progression of CAC as whites.This work contributes uniquely to public health significance. Future studies exploring reasons of poorer compensation of increasing insulin resistance by enhanced insulin secretion in Japanese in Japan may help to prevent earlier onset of type 2 diabetes in Japanese than whites at a given level of BMI. The second and third manuscripts identify increasing subclinical atherosclerosis in Japanese Americans that may translate into increased risk of CHD in Japanese Americans in the future. The second and third manuscripts identify Japanese American as a target group for prevention of CHD.