American Journal of Epidemiology Advance Access originally published online on August 28, 2007
American Journal of Epidemiology 2007 166(11):1280-1287; doi:10.1093/aje/kwm201
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ORIGINAL CONTRIBUTIONS |
Coronary Artery Calcification in Japanese Men in Japan and Hawaii
1 Division of Biostatistics and Epidemiology, University of Virginia School of Medicine, Charlottesville, VA
2 Department of Health Science, Shiga University of Medical Science, Otsu, Shiga, Japan
3 Pacific Health Research Institute, Honolulu, HI
4 Honolulu Heart Program and Honolulu-Asia Aging Study, Kuakini Medical Center, Honolulu, HI
5 Department of Geriatric Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI
6 Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA
7 Cardiovascular Institute, University of Pittsburgh, Pittsburgh, PA
8 Department of Internal Medicine, Korea University School of Medicine, Seoul, South Korea
9 Department of Internal Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
10 Cardiovascular Epidemiology, Kyoto Women's University, Kyoto, Japan
11 Holistica Hawaii, LLC, Honolulu, HI
Correspondence to Dr. Robert D. Abbott, University of Virginia Health System, Department of Public Health Sciences, P.O. Box 800717, Charlottesville, VA 22908-0717 (e-mail: rda3e{at}virginia.edu).
Received for publication April 25, 2007. Accepted for publication June 12, 2007.
Explanations for the low prevalence of atherosclerosis in Japan versus the United States are often confounded with genetic variation. To help remove such confounding, the authors compared coronary artery calcification (CAC), a marker of subclinical atherosclerosis, between Japanese men in Japan and Japanese men in Hawaii. Findings were based on risk factors and CAC measured from 2001 to 2005 in 311 men in Japan and 300 men in Hawaii. Men were aged 40–50 years and without cardiovascular disease. After age adjustment, there was a threefold excess in the odds of prevalent CAC scores of 
10 in Hawaii versus Japan (relative odds = 3.2, 95% confidence interval: 2.1, 4.9). Whereas men in Hawaii had a generally poorer risk factor profile, men in Japan were four times more likely to smoke cigarettes (49.5% vs. 12.7%, p < 0.001). In spite of marked risk factor differences between the samples, none of the risk factors explained the low amounts of CAC in Japan. After risk factor adjustment, the relative odds of CAC scores of 10 in Hawaii versus Japan was 4.0 (95% confidence interval: 2.2, 7.4). Further studies are needed to identify factors that protect against atherosclerosis in Japanese men in Japan.
atherosclerosis; cohort studies; coronary disease; Japan; men; risk factors
Abbreviations: CAC, coronary artery calcification