THE USE OF A COMPLEX THERMOHYGROMETRIC INDEX IN PREDICTING ADVERSE HEALTH-EFFECTS IN ATHENS

Mortality and morbidity indices are known to depend on changes in mete orological conditions. In Athens, severe adverse health effects follow ing extreme heat conditions have been reported. The usefulness has bee n investigated of the complex thermohygrometric index (THI), a simple index based on maximum daily temperature and relative humidity, in pre dicting the health effects of specific meteorological conditions. The values of THI were found to correlate well with more complex bioclimat ic indices: the THI could successfully replace temperature and humidit y in predicting the daily number of deaths through multiple linear reg ression modelling. Thus the introduction of THI levels more than 28.5 degrees C and between 26.5 and 28.5 degrees C, through dummy variables , in a regression model explained 40% of the variability in the number of deaths during the months of July and August. During days with THI values less than 26.5 degrees C the mean number of deaths was 33.5, co mpared to 41.8 when THI was between 26.5 and 28.5 degrees C. The daily number of deaths increased to 108.2 when THI exceeded 28.5 degrees C. From this study, the exact level of THI at which public health measur es must be taken was not clear and more work is needed to identify it. However, given its simplicity, the use of THI for predicting meteorol ogical conditions which are adverse to health would appear to be promi sing in preventive medicine and in health services planning.