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Mortality attributable to heat and cold among the elderly in Sofia, Bulgaria

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Abstract

Although a number of epidemiological studies have examined the effects of non-optimal temperatures on mortality in Europe, evidence about the mortality risks associated with exposures to hot and cold temperatures in Bulgaria is scarce. This study provides evidence about mortality attributable to non-optimal temperatures in adults aged 65 and over in Sofia, Bulgaria, between 2000 and 2017. We quantified the relationship between the daily mean temperature and mortality in the total elderly adult population aged 65 and over, among males and females aged 65 and over, as well as individuals aged 65–84 and 85 years or older. We used a distributed lag non-linear model with a 25-day lag to fully capture the effects of both cold and hot temperatures and calculated the fractions of mortality attributable to mild and extreme hot and cold temperatures. Cold temperatures had a greater impact on mortality than hot temperatures during the studied period. Most of the temperature-attributable mortality was due to moderate cold, followed by moderate heat, extreme cold, and extreme heat. The total mortality attributable to non-optimal temperatures was greater among females compared to males and among individuals aged 85 and over compared to those aged 65 to 84. The findings of this study can serve as a foundation for future research and policy development aimed at characterizing and reducing the risks from temperature exposures among vulnerable populations in the country, climate adaptation planning and improved public health preparedness, and response to non-optimal temperatures.

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The data used in this study are available from the corresponding author on reasonable request.

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Code availability

The code used in this study can be provided along with the publication or upon request.

Funding

This study was partially funded by the Frontiers of Science Program at Columbia University. In addition, AG and FS were supported by the Medical Research Council-UK (Grant ID: MR/M022625/1), the Natural Environment Research Council UK (Grant ID: NE/R009384/1), and the European Union’s Horizon 2020 Project Exhaustion (Grant ID: 820655).

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Authors and Affiliations

  1. Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA

    Elisaveta P. Petkova

  2. Department of Computer and Information Technology, Prof. Asen Zlatarov University, Burgas, Bulgaria

    Lyudmila K. Dimitrova

  3. Department of Public Health, Environments and Society, London School of Hygiene and Tropical Medicine, London, WC1H 9SH, UK

    Francesco Sera & Antonio Gasparrini

  4. Centre for Statistical Methodology, London School of Hygiene and Tropical Medicine, London, UK

    Antonio Gasparrini

  5. Centre on Climate Change and Planetary Health, London School of Hygiene and Tropical Medicine, London, UK

    Antonio Gasparrini

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  1. Elisaveta P. Petkova
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  2. Lyudmila K. Dimitrova
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  3. Francesco Sera
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  4. Antonio Gasparrini
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Correspondence to Elisaveta P. Petkova.

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Petkova, E.P., Dimitrova, L.K., Sera, F. et al. Mortality attributable to heat and cold among the elderly in Sofia, Bulgaria. Int J Biometeorol 65, 865–872 (2021). https://doi.org/10.1007/s00484-020-02064-y

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