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

Abstract

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.

Article summary

Article focus

• The incidence of coronary heart disease among urban middle-aged Japanese men increased from the 1990s to the 2000s, therefore the incidence of sudden cardiac death (SCD) may have increased in recent decades.

• This is the first study to examine recent trends in SCD in Japan.

Key messages

• The age-adjusted and sex-adjusted incidence of SCD among men and women aged 30–84 years in four Japanese communities decreased from 1981–1985 to 1991–1995 and plateaued after 1996.

• Continuous surveillance is necessary to clarify future trends in SCD in Japan because of an increasing incidence of diabetes mellitus.

Strengths and limitations of this study

• Trends in SCD were analysed using population-based data from a large number of participants in a long-term observational study and annual cardiovascular risk factor surveys ascertained the trends in predisposing risk factors of SCD.

• The incidence of SCD was only examined for people aged 30–84 years; other age ranges were not included.

• Clinical features and neuroimaging reports were used to exclude death due to stroke; some cases may have been misclassified, especially out-of-hospital deaths.