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Heart doi:10.1136/heartjnl-2013-304421
  • Epidemiology
  • Original article

Long chain n-3 polyunsaturated fatty acids and incidence rate of coronary artery calcification in Japanese men in Japan and white men in the USA: population based prospective cohort study

  1. for the ERA JUMP Study Group
  1. 1Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
  2. 2Department of Health Science, Shiga University of Medical Science, Otsu, Shiga, Japan
  3. 3Department of Medicine, Temple University, Philadelphia, Pennsylvania, USA
  4. 4Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
  5. 5Department of Preventive Medicine and Public Health, Keio University, Tokyo, Japan
  6. 6Department of Geriatric Medicine, University of Hawaii, Honolulu, Hawaii, USA
  7. 7Department of Cardiovascular Epidemiology, Kyoto Women's University, Kyoto, Japan
  8. 8Osaka Kyoiku University, Kashiwara, Osaka, Japan
  9. 9Internal Medicine & Cardiology, Queen's Hospital, Honolulu, Hawaii, USA
  10. 10Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
  1. Correspondence to Dr Akira Sekikawa, Graduate School of Public Health, University of Pittsburgh, 130 North Bellefield Avenue, Suite 546, Pittsburgh, PA 15213, USA; akira{at}pitt.edu
  • Received 6 June 2013
  • Revised 7 November 2013
  • Accepted 8 November 2013
  • Published Online First 18 December 2013

Abstract

Objective To determine whether serum concentrations of long chain n-3 polyunsaturated fatty acids (LCn3PUFAs) contribute to the difference in the incidence rate of coronary artery calcification (CAC) between Japanese men in Japan and white men in the USA.

Methods In a population based, prospective cohort study, 214 Japanese men and 152 white men aged 40–49 years at baseline (2002–2006) with coronary calcium score (CCS)=0 were re-examined for CAC in 2007–2010. Among these, 175 Japanese men and 113 white men participated in the follow-up exam. Incident cases were defined as participants with CCS≥10 at follow-up. A relative risk regression analysis was used to model the incidence rate ratio between the Japanese and white men. The incidence rate ratio was first adjusted for potential confounders at baseline and then further adjusted for serum LCn3PUFAs at baseline.

Results Mean (SD) serum percentage of LCn3PUFA was >100% higher in Japanese men than in white men (9.08 (2.49) vs 3.84 (1.79), respectively, p<0.01). Japanese men had a significantly lower incidence rate of CAC compared to white men (0.9 vs 2.9/100 person-years, respectively, p<0.01). The incidence rate ratio of CAC taking follow-up time into account between Japanese and white men was 0.321 (95% CI 0.150 to 0.690; p<0.01). After adjusting for age, systolic blood pressure, low density lipoprotein cholesterol, diabetes, and other potential confounders, the ratio remained significant (0.262, 95% CI 0.094 to 0.731; p=0.01). After further adjusting for LCn3PUFAs, however, the ratio was attenuated and became non-significant (0.376, 95% CI 0.090 to 1.572; p=0.18).

Conclusions LCn3PUFAs significantly contributed to the difference in the incidence of CAC between Japanese and white men.