[Circadian variations of sudden death].
Characteristics of the circadian variation for sudden death (SD), were studied by analyzing summary death certificates for the period of 1984 to 1986 in Niigata prefecture. SD was defined as death within 2 hours of onset of underlying cause (n = 4,362), and the time of onset of the cause was determined by subtracting the "time elapsed until death" from the "time of death." The periodicity for time of onset of the cause was analyzed in groups stratified by year, season, sex and age with Rogers' method utilized to check the statistical significance of the periodicity. SD, as a whole, showed a statistically significant circadian variation with a low incidence during 0 to 4 A.M. and a high incidence during 6 to 8 A.M. and 6 to 8 P.M. By season, no significant circadian variation was seen in the summer unlike for other seasons. When analyzed by age group, no significant circadian variation in SD was seen for the young to middle aged group (15-54 years old). On the other hand, there was a significant circadian variation for the senior (55 to 74 years old) and the elderly group (75 years old or older) with a low incidence during 0 to 4 A.M. and high incidence during 6 to 12 A.M. and 6 to 8 P.M.. For the old age group, the number of the cases increased so remarkably as to form an evening peak. The percentage of SD for young to middle cases was higher in the summer than in the other seasons which may be the reason for absence of significant circadian variation in the summer.
Hayashi
S
S
Department of Public Health, Niigata University School of Medicine.
Toyoshima
H
H
Miyanishi
K
K
Tanabe
N
N
Funazaki
T
T
Obata
A
A
Kamimura
K
K
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002940:Circadian Rhythm / Q000502:physiology*; D003645:Death, Sudden / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012621:Seasons; D012737:Sex Factors