Impact of Temperature in Summer on Emergency Transportation for Heat-Related Diseases in Japan

摘要

Background:In Japan,the demand for emergency transportation for people with heat-related illness has recently increased.The purpose of this study was to investigate the relationship between incidents of heat-related illness and the daily maximum temperature.Methods:The daily maximum temperatures in Japan's 11 districts over the past 10 years were classified into four categories,with cutoff points at the 50th,75th,95th,and higher than 95th percentiles.We then conducted a logistic regression analysis of emergency transportation demand in each temperature category by age group,using the 50th percentile as the reference category for each area.Results:There were 42,931 cases of emergency transportation due to heat-related diseases during the study period.Classified by age,12.5％,43.4％,and 44.1％ of cases involved children,adults,and elderly people,respectively.The analysis showed that the number of cases of emergency transportation for people with heat-related diseases (per 100,000 people;corresponding to a 1.0℃ increase in the daily maximum temperature) was 0.016-0.106 among children (24.9-169.9 children required emergency transportation for heat-related diseases),from 0.013 to 0.059 among adults (19.8-98.2 adults required emergency transportation),and from 0.045 to 0.159 among elderly persons (30.0-145.4 elderly people required emergency transportation).The risk was highest for elderly persons,followed by children and finally adults.Cases of emergency transportation due to heat-related illness increased by 2.4-8.9 times when the daily maximum temperature was approximately 1.5℃ above the mean daily maximum temperature.In fact,the daily maximum temperature had a larger effect than the daily relative humidity level on emergency transportation for people with heat-related diseases.Conclusion:Public health organizations and health-care services should support elderly people and children,two high-risk groups for heat-related diseases.