Excess Risk of Mortality Due to Heatwaves in Dezful city, Southwest of Iran

Background: Recent studies show that heatwaves pose risks to human health. Iran is exposed to heatwaves, but the evidence for the health impact of heatwaves is scarce. We aimed to evaluate the impact of heatwaves on daily deaths from non-accidental, cardiovascular, and respiratory in the city of Dezful in Iran from 2013 to 2019. Method: We collected daily ambient temperature and mortality and defined two types of heatwaves by combining daily temperature ³90 th in each month of the study period or since 30 years with duration ³2 and 3 days. We used a distributed lag non-linear model to investigate the association between each type of heatwave definition and deaths from non-accidental, cardiovascular, and respiratory with lags up to 13 days. Results: : Heat waves of both definitions were associated with a higher risk of non-accidental mortality. The association between heat waves and mortality appeared acutely and lasted for 3 and 4 days. The main effect and added effect are more pronounced among male and older adults than their counterparts. We found no evidence of an association of cardiovascular and respiratory deaths with heat waves. Conclusion: Dezful is a city with a hot climate. However, the results showed that heatwaves could have detrimental effects on health, even in populations accustomed to the extreme heat. Therefore, early warning systems which monitor heat waves should provide the necessary warnings to all exposed groups, especially the elderly and the male groups.