Seasonal changes in mortality rates from main causes of death in Japan (1970--1999).
BACKGROUND
It is well recognized that the season of the year exerts an influence on some diseases and causes of death such as coronary heart diseases, stroke, infectious diseases and so on.


METHODS
We evaluated the influence of seasonal changes on diseases and causes of death in Japan using the Japan Vital Statistics from 1970 to 1999 and recorded weather data (mean temperature), by a Fourier decomposition in a log linear regression model.


RESULTS
Major influences of seasonal change with the highest rates in winter were seen on the following: the overall causes of death; infectious and parasitic diseases including tuberculosis; respiratory disease, including pneumonia and influenza; heart and cerebrovascular diseases; diabetes; and digestive diseases and accidents. Two peaks were seen in suicides, a large peak in April and a small peak in autumn. Cancer and homicides were little or not at all influenced by seasonality. There was no major difference in changes between the years studied, except for respiratory disease and tuberculosis, which showed a clear reduction in the seasonality effect from 1970 to 1999.


CONCLUSIONS
To reduce the overall mortality rate and to prolong life expectancy in Japan, measures must be taken to reduce those mortality rates associated with seasonal differences, especially those causes of death which show a strong correlation with seasonal change: respiratory, heart, cerebrovascular, diabetes and infectious diseases.
Nakaji
Shigeyuki
S
Department of Hygiene, Hirosaki University School of Medicine, Zaifu-cho 5, Hirosaki, Japan. nakaji@cc.hirosaki-u.ac.jp
Parodi
Stefano
S
Fontana
Vincenzo
V
Umeda
Takashi
T
Suzuki
Katsuhiko
K
Sakamoto
Juichi
J
Fukuda
Shinsaku
S
Wada
Seiko
S
Sugawara
Kazuo
K
D000063:Accidents, Traffic / Q000401:mortality; D020520:Brain Infarction / Q000401:mortality; D002318:Cardiovascular Diseases / Q000401:mortality; D002423:Cause of Death / Q000639:trends; D003920:Diabetes Mellitus / Q000401:mortality; D004066:Digestive System Diseases / Q000401:mortality; D006331:Heart Diseases / Q000401:mortality; D006708:Homicide / Q000706:statistics & numerical data; D006801:Humans; D007564:Japan / Q000453:epidemiology; D009369:Neoplasms / Q000401:mortality; D012140:Respiratory Tract Diseases / Q000401:mortality; D012621:Seasons; D013405:Suicide / Q000706:statistics & numerical data; D013696:Temperature