Mortality Risk Related to Heatwaves in Dezful City, Southwest of Iran

Hamidreza Aghababaeian; Abbas Ostadtaghizadeh; Ali Ardalan; Ali Asgary; Mehry Akbary; Mir Saeed Yekaninejad; Rahim Sharafkhani; Carolyn Stephens

doi:10.1177/11786302231151538

Mortality Risk Related to Heatwaves in Dezful City, Southwest of Iran

Environ Health Insights. 2023 Jan 30:17:11786302231151538. doi: 10.1177/11786302231151538. eCollection 2023.

Authors

Hamidreza Aghababaeian^{1

2}, Abbas Ostadtaghizadeh^{2

3}, Ali Ardalan², Ali Asgary⁴, Mehry Akbary⁵, Mir Saeed Yekaninejad⁶, Rahim Sharafkhani⁷, Carolyn Stephens⁸

Affiliations

¹ Center for Climate Change and Health research (CCCHR), Dezful University of Medical Sciences, Dezful, Iran.
² Department of Health in Emergencies and Disasters, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
³ Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.
⁴ Disaster and Emergency Management, School of Administrative Studies, York University, Toronto, Canada.
⁵ Department of Climatology, Faculty of Geographical Sciences, Kharazmi University, Tehran, Iran.
⁶ Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
⁷ School of Public Health, Khoy University of Medical Sciences, Khoy, Iran.
⁸ UCL Bartlett Development Planning Unit, London School of Hygiene & Tropical Medicine, London, UK.

Abstract

Background: We aimed to evaluate the impact of heatwaves on daily deaths due to non-accidental, cardiovascular and respiratory causes in the city of Dezful in Iran from 2013 to 2019.

Method: We collected daily ambient temperature and mortality and defined 2 types of heatwaves by combining daily temperature ⩾90th in each month of the study period or since 30 years with duration ⩾2 and 3 days. We used a distributed lag non-linear model to study the association between each type of heatwave definition, and deaths due to non-accidental, cardiovascular and respiratory causes with lags up to 13 days.

Results: There was no discernible correlation in this area, despite the fact that heatwaves raised the risk of death from cardiovascular causes and lowered the risk from respiratory causes. On the other hand, the risk of total non-accidental mortality on days with the heatwaves is significantly higher than normal days. In main effects, the heatwaves have a significant relationship with the risk of total non-accidental mortality (in the first heatwave definition, Cumulative Excess Risk (CER) in lag_0-2 was 10.4 and in second heatwave definition, CER values in lag_{0, 0-2, and 0-6} were 12.4, 29.2, and 38.8 respectively). Also, in added effects, heatwaves have a significant relationship with the risk of total non-accidental mortality (in the first heatwave definition, CER in lag_{0 and 0-2} were 1.79 and 4.11 and in the second heatwave definition, CER values in lag_{0, 0-2, and 0-6} were 7.76, 18.35 and 24.87 respectively). In addition, heatwaves appeared to contribute to a cumulative excess risk of non-accidental death among the male group as well as the older adults.

Conclusion: 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 heatwaves should provide the necessary warnings to the population, especially the most vulnerable groups.

Keywords: Climate change; disaster; health; heatwave; mortality.