Changing CHD mortality and its causes in Japan during 1955-1985.

Coronary heart disease (CHD) mortality has been decreasing continuously in all age-sex groups in Japan since 1976. An earlier increase in the 1950s was largely due to a change in the diagnostic method. Hypertension was a more important risk factor than hyperlipidaemia for ischaemic heart disease (IHD) in Japan. Increasing availability of a variety of foods supplying balanced nutrition, opportunities for health screening linked to detection and treatment of high blood pressure with little financial constraint, plus health insurance and health education have improved the cardiovascular health of the people, though these effects have not been evaluated objectively. These changes resulted in less advanced coronary atherosclerosis and less CHD despite a high frequency of smoking in men. Improving technology in the treatment of acute myocardial infarction (MI) may also have contributed to the decline in mortality.