A Cohort Phenomenon of Death from Heart Disease in Japan

Abstract

The Cohort Phenomenon was reported firrt on English data on the death rate from peptic ulcer in the War time by Susser, which means the findings of the fixed level of death rate by ageing of age-group for several years after the exposure to the agent that was a psycho-somatic stress from the war. In this country, Japan, we have not enough reports on the cohort phenomenon on death rates from diseases, yet. In this paper we presented a cohort phenomenon showed on the death rate from heart diseases (B26, 28 and 29) after the War in Japan. The trace of death rates from heart diseases of each 5-years-old class gives approximate straight lines by years from 1940 to 1970 in both sexes on a semi-logarithmic section paper, and these lines show a counter-clockwise rotation almost showing a center near the point that is made by cross-ing of scales of 65-years-old of age and of 450-per-100, 000 of death rate in male and of scales of the same of age and of 400-per-100, 000 of death in female. The rotation of death rate lines is made from what that, younger age-groups under 65 years-old of age show almost the same death from heart diseases in these 30 years and older ones show rapid increaing of death rate in the same period in the opposition. Namely, those who are in age groups under 65 years-old of age show cohort poenomena in thses 30 years in Japan. The rotation of death rate lines show the highest speed between in 1955 and in 1960.