| |
|---|---|
 (529KB)
|
13,743,000Yen (FY 1998; 3,639,000 Yen)
Global warming, Living temperature, Maximum ambient temperature, Lifestyle, R-R interval, Health risk
We predicted mortality risk by global warming using statistics of 1972-1995. The relationship between daily maximum temperature and daily mortality was confirmed to show clear V-shape in 65 years old and over when the daily maximum temperature excecds 33 degrees in Celsius. Chronological changes between three phases (1970-79, 1980-89, and 1990-95) showed simple shift of the bottom in V-shape to the right in Hokkaido, but lowering of deaths at 33 degrees and over (from V-shape to L-shape) in Kyushu and Tokyo during last two phase (1980-89, 1990-1995). It suggests the possibility of different adaptation to global warming. Prediction of the future health risk by GIS specification was done based on the temperature-death rate model (Honda, 1995) . However, the analysis of more complex effect,s other than death, which change by time and location, and of factors in urban environment. As a trial we will select proper indices of solar radiation and heat load and develop models of dynamic changes including both individual and environment.
On the other hand, it is difficult to get precise death statistics with death cause in Thailand, we collected individual death records accompanied by date and cause from major hospitals in and around Bangkok. Because of most death causes are sepsis due to tropical infections and delayed treatment, and poor seasonal and daily change in ambient temperature, it is difficult to evaluate temperature effects and to find strategies to rceuce deaths.
We studied spectrum analysis of the R-R interval dcviation of the ECG (analysis of R-R interval) to identify the response of elderly men (60-75 years old) under heat stress. They showed clearly decreased responsiveness to adapt autonomic nervous system to heat stress compared with young men of 20 years old, though changes in other physiologic parameters (rectal temperature, blood pressure, heart rate, skin temperature, and perspiration) were not consistent. It suggests that elderly people have poor subjective sensation against heat stress, lack of more sympathetic tone than parasympathetic tone or even rather reversed balance which indicate the presence of subgroup with absence or prolonged delay of normal adaptation mechanism shown by young people. In addition, in Thailand and Japan, we are analyzing adaptation mechanisms