本邦の石油ショック期における職業に由来する精神的ストレスと急性心筋梗塞発症の関連について

―全国剖検例を用いた統計学的研究―

抄録

Mental stress from one's occupational circumstances is considered an important risk factor in the occurrence of myocardial infarction. However, because of difficulty in quantitative evaluation of such stress, this issue has not been fully studied. In the present work, we investigated the relationship between deaths from acute myocardial infarction (AMI) and occupation using data from the series of the Annual of the Pathological Autopsy Cases in Japan, in which autopsy cases throughout Japan are described. With regard to the 56, 268 persons who died at the age of 15 or older in 1973, 1974 and 1975, i. e., the year of economic depression due to the first oil shock and the years before and after the oil shock, we compared (I) the mortalities from AMI and frequencies of such deaths among all autopsy cases in Japan in relation to the occupational group in the three years and (II) the mortalities from AMI according to the occupation among 3, 241 randomly selected deaths in the three years. The mortality from AMI for 1973, 1974 and 1975 was 2.6%, 3.7% and 3.0%, respectively, showing a significantly higher value for 1974 (p<0.001). Among persons who died from AMI, the proportion of mental workers, particularly executives and managers, and unemployed/retired individuals was significantly higher (p<0.05) in 1974. As for randomly selected autopsy cases, the mortalities from AMI among mental workers in 1973, 1974 and 1975 were 7.8%, 17.0% and 6.2%, respectively, and the corresponding rates among physical workers were 2.0 %, 1.8% and 2.6%. Thus, the mortality among mental workers was significantly increased in 1974 (p<0.05), whereas there were no such variations among physical workers. In addition to the corroboration with the previous experience that deaths from AMI are more frequent among mental workers, particularly executives and managers, than among physical workers, we noted an increase in moratlity from AMI in the period of economic depression. It seems that stress derived from occupational circumstances rather than limited physical activities is involved in the occurrence of AMI.