Trends in sudden cardiac death and its risk factors in Japan from 1981 to 2005: the Circulatory Risk in Communities Study (CIRCS)

OBJECTIVE: There is little evidence whether sudden cardiac death (SCD) is increasing in Asia, although the incidence of coronary heart disease among urban middle-aged Japanese men has increased recently. We examined trends in the incidence of SCD and its risk factors in the Circulatory Risk in Communities Study. DESIGN AND SETTING: This was a population-based longitudinal study. Surveillance of men and women for SCD incidence and risk factors was conducted from 1981 to 2005. SUBJECTS: The surveyed population was all men and women aged 30–84 years who lived in three rural communities and one urban community in Japan. MAIN OUTCOME MEASURES: Trends in SCD incidence and its risk factors. RESULTS: Age-adjusted and sex-adjusted incidence of SCD decreased from 1981–1985 to 1991–1995, and plateaued thereafter. The annual incidence per 100 000 person-years was 76.0 in 1981–1985, 57.9 in 1986–1990, 39.3 in 1991–1995, 31.6 in 1996–2000 and 36.8 in 2001–2005. The prevalence of hypertension decreased from 1981–1985 to 1991–1995, and plateaued thereafter for men and women. The age-adjusted prevalence of current smoking for men decreased while that of diabetes mellitus increased for both sexes from 1981–1985 to 2001–2005. CONCLUSIONS: The incidence of SCD decreased from 1981 to 1995 but was unchanged from 1996 to 2005. Continuous surveillance is necessary to clarify future trends in SCD in Japan because of an increasing incidence of diabetes mellitus.