Less Subclinical Atherosclerosis in Japanese Men in Japan than in White Men in the United States in the Post-World War II Birth Cohort

Abstract

Coronary heart disease incidence and mortality remain very low in Japan despite major dietary changes and increases in risk factors that should have resulted in a substantial increase in coronary heart disease rates (Japanese paradox). Primary genetic effects are unlikely, given the substantial increase in coronary heart disease in Japanese migrating to the United States. For men aged 40-49 years, levels of total cholesterol and blood pressure have been similar in Japan and the United States throughout their lifetimes. The authors tested the hypothesis that levels of subclinical atherosclerosis, coronary artery calcification, and intima-media thickness of the carotid artery in men aged 40-49 years are similar in Japan and the United States. They conducted a population-based study of 493 randomly selected men: 250 in Kusatsu City, Shiga, Japan, and 243 White men in Allegheny County, Pennsylvania, in 2002-2005. Compared with the Whites, the Japanese had a less favorable profile regarding many risk factors. The prevalence ratio for the presence of a coronary calcium score of > or =10 for the Japanese compared with the Whites was 0.52 (95% confidence interval: 0.35, 0.76). Mean intima-media thickness was significantly lower in the Japanese (0.616 mm (standard error, 0.005) vs. 0.672 (standard error, 0.005) mm, p < 0.01). Both associations remained significant after adjusting for risk factors. The findings warrant further investigations.

Association between Pulse Wave Velocity and Coronary Artery Calcification in Japanese men

“…A CAC score was calculated based on the methods of Agatston 26) . An Agatston score ≥ 10 is defined as definite CAC 27) . All CT images were read by a trained physician who was blinded from clinical information from the participants.…”

“…All CT images were read by a trained physician who was blinded from clinical information from the participants. The protocol described was adopted from a previous study 8) in which the reproducibility of the scans showed an intraclass correlation of 0.98 27) . Since results of the current report are similar to the results of factors.…”

LOX-1 Ligands Containing Apolipoprotein B and Carotid Intima-media Thickness in Middle-aged Community-dwelling US Caucasian and Japanese Men

“…Details of the study methods were described elsewhere. [15][16][17][18] A total of 623 Japanese and US Caucasian men aged 40-49 years without past history of cardiovascular disease (310 US Caucasian men from Allegheny County, Pennsylvania, US and 313 Japanese men from Kusatsu City, Shiga, Japan) were randomly selected from each community. Informed consent was obtained from all participants.…”

“…Serum total cholesterol (TC), high-density-lipoprotein cholesterol (HDL-C), triglycerides (TG) and glucose were measured. [15][16][17][18] LDL-C was estimated by the Friedewald formula. [19] Creactive protein (CRP) was measured by an immunosorbent assay and total LDL particles were measured by nuclear magnetic resonance (NMR) spectroscopy.…”

“…[15][16][17][18] We applied continuous-qualityassessment programs developed by the laboratory to assure the scanning quality within and between sites.…”