Physiological Equivalent Temperature (PET) Index and cardiovascular and respiratory hospital admissions in Ahvaz, southwest of Iran

Abstract

Physiological Equivalent Temperature (PET) Index and cardiovascular and respiratory hospital admissions in Ahvaz, southwest of IranBackground: Evidence has shown that climate change may have adverse effects on human health.Although Ahvaz is one of the hottest cities in the world, there have been no studies on the effect of ambient heat on hospital admission rates.The purpose of this study was to investigate the relation between Physiologically Equivalent Temperature (PET) and cardiovascular and respiratory hospital admissions in Ahvaz.Methods: Distributed Lag Non-linear Models (DLNM) combined with quasi-Poisson regression were used to investigate the effect of PET on hospital admissions. In this study the effect of time trend, air pollutants (NO2, SO2 and PM10), and weekdays were adjusted.Results: The results demonstrated that low PET values (6.4°C, 9.9°C and 16.9°C) in lags 0, 0-2, 0-6, 0-13 and 0-20,significantly decreasedthe risk ofhospital admissionsfortotalcardiovascular diseases,hypertension, ischemic heart diseases, cardiovascular admissionsin men, women and less than 65 year olds. Also, low PET values significantly decreased the riskof hospital admissions for total respiratory diseases, respiratory diseases in men and women, chronic obstructive pulmonary disease (COPD) and bronchiectasis. In contrast, low PET values in all lags except lag 0-30significantlyincreased the risk of hospital admissionsforasthma and strokes. High PET values (43.6°C and 45.4°C) increased the risk of cardiovascular and ischemic heart diseases in men.Conclusions: The results indicate that in Ahvaz which has a warm climate, cold stressesare more involved in cardiovascular and respiratory hospital admissions; and cold stress decreased overall cardiovascular and respiratory hospital admissions, except for asthma and stroke.