A note on cardiovascular diseases and physical aspects of the environment

This paper presents a biometeorological study of ischaemic heart diseases and a thermal load index combining meteorological factors, clothing insulation and metabolic rate. The study is based on records of weather and of hospital admissions. The data were grouped into four seasonal periods approximating the four major climate seasons experienced at Toronto, Canada. Statistical analysis of the seasonal data for five years (1976–1980) shows a good association between the deviations from group averages of the thermal load index and corresponding deviations of the number of patients admitted to hospitals at Toronto due to cardiovascular diseases if two out of nineteen data points are excluded from the analysis. In the authors' view, recognizing the nature of climate and other records, there is good reason to believe that this association is meaningful. The results indicate that at a given activity level and clothing insulation there is a higher incidence of coronorary diseases when the thermal sensation is to the cold side of the neutral comfort condition. Probable causes are advanced for the fact that 12% of the data appear anomalous.