A survey of sudden death among school children in Osaka Prefecture.

For 2 years, from January 1985 to December 1986, we carried out a thorough investigation of sudden death or apparent sudden death in a population between 5 and 19 years of age in Osaka Prefecture. Sudden death (unexpected death caused by intrinsic factors within 24 h after the onset of symptoms) occurred in 62 boys and 30 girls, with an annual sudden death rate of 3.0 per 100,000 for boys and 1.5 per 100,000 for girls. Of these 92 deaths, 64 occurred among school children (elementary or high school students), and it was these that were subjected to further analyses. Of the school children deaths, 29.7% seemed to be apparent sudden cardiac death (based on circumstances immediately before death, although there was no definite evidence for sudden cardiac death), and 29.7% were sudden death clearly attributable to underlying heart diseases (hence, sudden cardiac death in the usual meaning of this term accounted for about 60% of the 64 sudden deaths). In addition, 17.2% of the 64 cases were sudden death from bronchial asthma. Analysis of seasonal variation in the incidence of sudden death showed that apparent sudden cardiac death frequently occurred in summer, while sudden death clearly attributable to underlying cardiac diseases often took place in winter, sudden death from bronchial asthma occurred chiefly in summer and fall. Of the total number of sudden deaths, death occurred during exercise in 29.7%, and during sleep in 18.8% of individuals. The percentage of sudden deaths occurring during school hours was as low as 23.4% (15/64). Analysis of the physical condition of the 64 sudden death cases immediately before death disclosed the presence of respiratory infection in 10.9%, fatigue in 21.9%, lack of sleep in 4.7% and other conditions in 4.7%. Thus, the percentage of sudden deaths which occurred under ordinary physical conditions was 57.8% (37/64), of which 14 deaths (21.9% of the total) were associated with exercise.