Lifetime Risk of Acute Myocardial Infarction in Japan

Abstract

The incidence and mortality from coronary heart disease (CHD) in Japan are reported to be among the lowest of all industrialized countries,1,2 but, in the backdrop of major dietary changes and worsening cardiovascular risk factors,2 recent reports have shown an increasing trend of acute myocardial infarction (AMI) in the Japanese population.3,4 With the aging of the population and the presence of unfavorable cardiovascular risk factor scenario, AMI is likely to be an increasingly important health burden in Japan. Thus, prevention of AMI requires urgent attention. Lifetime risk (LTR) is an epidemiological measure that expresses the probability of disease in the remaining lifetime for an index age. Estimation of the LTR of AMI, which provides an absolute risk assessment, has not yet been reported for the Japanese population. In the present study, we estimated the short- and intermediate-term risks and LTR of AMI in a Japanese population. The Suita study,5 a cohort study for cardiovascular disease (CVD) established in 1989, randomly sampled Suita city residents ages 30 to 79 years and stratified the residents by sex and age class (10-year increments). From this sample, 6485 participated in the baseline survey between 1989 and 1994 (participation rate, 53.2%) at the National Cerebral and Cardiovascular Center, Osaka. After excluding participants with a history of CVD (n=208) and those lost to follow-up (n=779; predominantly because of moving out of Suita city after consenting to participate in the study, but before partaking in the baseline survey), data from the remaining 5498 participants (2571 men and 2927 women) were included in the analysis. The follow-up for the present study ended either at (1) AMI occurrence, (2) death, (3) date of leaving Suita city, or (4) at December 31, 2005, whichever came first. Identifying possible AMI events involved checking …