Understanding the mechanisms of climate change impact on tuberculosis: a complex systems approach

Yahya Shadi; Esmaeil Khedmati Morasae; Salman Khazaei; Mahshid Nasehi; Saeed Sharafi; Hossein Asakereh; Leili Tapak; Zohreh Kahramfar; Younes Mohammadi

doi:10.1186/s12889-025-24709-6

Understanding the mechanisms of climate change impact on tuberculosis: a complex systems approach

BMC Public Health. 2025 Oct 8;25(1):3382. doi: 10.1186/s12889-025-24709-6.

Authors

Yahya Shadi¹, Esmaeil Khedmati Morasae², Salman Khazaei^{1

3}, Mahshid Nasehi^{4

5}, Saeed Sharafi⁵, Hossein Asakereh⁶, Leili Tapak⁷, Zohreh Kahramfar⁸, Younes Mohammadi^{9

10}

Affiliations

¹ Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
² Department of Management Science, Business School, University of Strathclyde, Glasgow, Scotland, UK.
³ Department of Epidemiology, Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran.
⁴ Department of Epidemiology, Iran University of Medical Sciences, Tehran, Iran.
⁵ Center for Communicable Diseases Control, Ministry of Health and Medical Education, Tehran, Iran.
⁶ Department of Geography, University of Zanjan, Zanjan, Iran.
⁷ Department of Biostatistics, School of Public Health and Modeling of Noncommunicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
⁸ Department of Internal Medicine, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
⁹ Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran. younesmohamadi@gmail.com.
¹⁰ Social Determinants of Health Research Center, Hamadan University of Medical Sciences, Hamadan, Iran. younesmohamadi@gmail.com.

Abstract

Background: Tuberculosis (TB) is a leading cause of disability and mortality in many countries and is the leading cause of death from an infectious agent worldwide. While TB is a curable and preventable disease, health systems' ineffectiveness in case finding and appropriate treatment results in 10 million new cases and 1.5 million deaths annually around the globe. Climate change is expected to have a major impact on TB and other infectious diseases, although the mechanisms for this are still poorly understood.

Methods: We undertook a systematic review of Literature published up to September 2024 about the effects of climate Change on TB incidence. The review identified 35 papers that described possible mechanisms for the impact of climate change on TB. We used a complex systems approach called causal loop diagramming to integrate the identified mechanisms into a system map of climate change effects on TB. A panel of experts on TB, epidemiology, and climate change reviewed the map's structure and content.

Results: The final map shows 6 reinforcing feedback loops and associated chains of complex bio-socio-technical interrelations through which climate change can affect TB risk. The loops included reciprocal relationships between heatwave - energy use, indoors time - airborne disease risk, food access - price, malnutrition - infectious disease, healthcare cost - detection delay, and infectious contact - TB risk that translate to TB infection, directly or indirectly, when activated.

Conclusions: The presented map illustrates and highlights the need for coordinated, multisectoral and complex interventions across that bio-socio-technical system to tackle the nexus of climate change and TB risk. In this context, identifying key leverage points and implementing strategic actions on these points are essential to effectively mitigate climate change-related risks and their impact on TB transmission and incidence.

Keywords: Climate change; Complex systems; Environmental determinants of health; Tuberculosis.

Publication types

Systematic Review

MeSH terms

Climate Change*
Global Health
Humans
Incidence
Tuberculosis* / epidemiology