Trends in the incidence of acute myocardial infarction in coastal and inland area in Japan: the AMI registry

Abstract

Purpose: It was reported that there are high consumption of fish and low incidence of acute myocardial infarction (AMI) in coastal area. Recently, there has been an increase in the prevalence of coronary risk factors, such as dyslipidemia and diabetes mellitus, as a result of Westernization of lifestyle in Japan. We reported that the incidence of AMI has increased in especially younger men in Japan. The purpose of this study was to investigate trends in the incidence of AMI and their coronary risk factors in coastal and inland areas. Methods: We investigated clinical characteristics using data from the AMI Registry among 1994-2010. We divided 5,915 first ever AMI patients into 3 groups according to the medical area where they were registered; coastal area (n=2,004), rural inland area (n=2,174) and urban inland area (n=1,737).There are 2 or 3 hospitals with cardiac catheterization facility in each area. Further, we divided observation period into 2 intervals, 1994-2002 and 2003-2010. Results: Patients in coastal area was significantly older (70.9±13, 69.6±13, 69.3±13 years old, respectively), and had a lower prevalence of dyslipidemia (23.6, 27.8, 32.2%, respectively) than patients in rural and urban inland areas. Age-adjusted incidence rate of AMI was significantly lower in patients in coastal area than in patients in rural and urban inland areas (32.5±4.8, 34.3±6.9, 41.0±6.2 /105 person-years, respectively), especially in younger (<64 years old) and early elderly (65-74 years old) patients. In the first period, patients in coastal area had the lowest age-adjusted incidence rate of AMI and prevalence of dyslipidemia among 3 groups. However, in second period, there were no significant differences in age-adjusted incidence rate of AMI and prevalence of dyslipidemia among 3 groups. The prevalence of dyslipidemia was significantly increased in all groups, especially in patients in coastal area. There was a greater increase in the incidence of AMI in younger and early elderly patients in coastal area compared with those in inland areas. Conclusions: It was suggested that an increase in the incidence of AMI in coastal area may be associated with increasing prevalence of dyslipidemia.