title: Much lower prevalence of coronary calcium detected by electron-beam computed tomography among men aged 40-49 in Japan than in the US, despite a less favorable profile of major risk factors.
abstract: BACKGROUND
  Since World War II (WWII), exposures to westernized lifestyle have occurred in many non-Western countries, including Japan. National surveys showed that risk factor profiles for atherosclerosis around 1990 were similar in men in the post WWII birth cohorts in the US and Japan. We compared the degree of coronary calcium and other factors in men in the post WWII birth cohort: men aged 40-49 in the US and Japan.
  
  
  METHODS
  We conducted a cross-sectional study examining randomly selected 100 men from Kusatsu, Japan, and 100 men from Allegheny County, US. Coronary calcium was assessed using electron-beam computed tomography.
  
  
  RESULTS
  Systolic blood pressure, total cholesterol, low density lipoprotein (LDL)-cholesterol, and smoking rates were higher among the Japanese (122.6 +/- 14.1 versus 113.7 +/- 9.6 mmHg, P < 0.01; 5.72 +/- 0.90 versus 4.99 +/- 0.81 mmol/l (220.9 +/- 34.6 versus 192.8 +/- 31.3 mg/dl), P < 0.01; 3.52 +/- 1.01 versus 3.10 +/- 0.78 mmol/l (136.0 +/- 39.0 versus 119.7 +/- 30.0 mg/dl), P < 0.01; and 48 versus 15%, P < 0.01, respectively). Triglycerides and fibrinogen were similar. High density lipoprotein (HDL)-cholesterol was higher among the Japanese. Body mass index, fasting insulin, and C-reactive protein were higher among the Americans. Prevalence of coronary artery calcium score >0 was strikingly lower among the Japanese than the Americans (13% versus 47%, P < 0.01).
  
  
  CONCLUSIONS
  Much lower prevalence of coronary calcium despite a less favourable profile of many major independent risk factors in the Japanese might imply that there are strong protective factors against atherosclerosis in the Japanese. Further investigation is of critical importance.
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, 3512 Fifth Avenue, Pittsburgh, PA 15213, USA. akira@pitt.edu
authors.forename: Akira
authors.initials: A
authors.lastname: Sekikawa
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ueshima
authors.forename: Wahid Riad
authors.initials: WR
authors.lastname: Zaky
authors.forename: Takashi
authors.initials: T
authors.lastname: Kadowaki
authors.forename: Daniel
authors.initials: D
authors.lastname: Edmundowicz
authors.forename: Tomonori
authors.initials: T
authors.lastname: Okamura
authors.forename: Kim
authors.initials: K
authors.lastname: Sutton-Tyrrell
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Katsuya
authors.initials: K
authors.lastname: Egawa
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kanda
authors.forename: Atsunori
authors.initials: A
authors.lastname: Kashiwagi
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maegawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Mitsunami
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Murata
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nishio
authors.forename: Shinji
authors.initials: S
authors.lastname: Tamaki
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Ueno
authors.forename: Lewis H
authors.initials: LH
authors.lastname: Kuller
mesh_terms: D000328:Adult; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000208:ethnology* / Q000209:etiology; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000208:ethnology / Q000209:etiology; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000208:ethnology* / Q000209:etiology; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D014481:United States / Q000453:epidemiology