Assessing Heat-Health Risks and Advancing Local Adaptation in the Asia-Pacific

Challenge

Extreme temperatures increase deaths and illnesses, yet cities and health systems often lack locally tailored guidance to reduce heat risks.

Solution

Build multi-city evidence on heat-health risks and translate it into practical adaptation options, tools, and guidance for local action.

Overview

Extreme temperatures are a leading cause of weather-related health harm. With support from the Asia-Pacific Network for Global Change Research (APN), Cunrui Huang (Sun Yat-sen University, China) led a multi-country project that assessed health risks from heat and cold and developed practical, locally usable adaptation options.

The work combined epidemiological analyses with policy design and risk communication to help decision-makers reduce risks before, during, and after heat events.

Project context and approach

The project linked health surveillance and meteorological records to understand how heat and cold affect people, then translated those findings into practical actions. It analyzed mortality, hospitalizations, occupational injuries, and emergency ambulance dispatches using time-series methods designed for daily health data. Temperature exposure used local indices, including apparent temperature (a combined measure of air temperature and humidity that reflects how hot it feels).

Years of life lost (YLL) captured the burden beyond simple death counts by weighting deaths by age. To capture delayed and non-linear effects, analyses used distributed-lag non-linear models, which estimate how risk changes with temperature over the following days. Analyses identified a local minimum-risk temperature to set heat thresholds and adjusted for humidity, air pressure, long-term trends, and day of week.

Alongside these analyses, the project reviewed options for heat-health warning systems, occupational protections, and risk communication that cities and health services can deploy.

Evidence across sites

Bangladesh

The partner institution contributed to the multi-country collaboration and supported the interpretation and regional application of findings. This work informed how local thresholds and warning triggers could be set and how adaptation priorities should be targeted.

China

Multiple sub‑studies drew on city health and labor databases. One case‑crossover study used workers’ compensation claims to assess heat–injury links in Guangzhou, and a related analysis estimated the economic burden of heat‑related work injuries. In Shenzhen, emergency ambulance dispatch records, grouped by initial diagnosis, identified which conditions and age groups surged on very hot days.

Additional analyses assessed first‑ever strokes with time‑series models that account for non‑linear and delayed effects of temperature, while scenario work explored how population aging and adaptation could alter future heat‑related mortality.

Thailand

A national assessment evaluated heatwave impacts on total and cause-specific mortality across 60 provinces. It tested 30 heatwave definitions grouped by intensity, incorporated evidence-based lag structures, and pooled provincial estimates to produce national patterns. Meta-regression helped explain why some regions were more affected than others.

Vietnam

Analyses covered Ho Chi Minh City and districts in the Mekong Delta. City‑level work compared mortality and hospitalizations across temperature ranges and during defined heatwaves, identifying a local minimum‑risk temperature and short‑lag effects on deaths. District‑level mapping characterized how vulnerability varies across the Mekong Delta.

Policy and adaptation options

The project set out concrete actions that public health and city agencies can implement. These include designing heat-health warning systems that use locally derived thresholds and clear action protocols for health services, social care, and the public; using real‑time ambulance dispatch surveillance to detect surges in demand and trigger rapid communication; and protecting outdoor and indoor workers with cooling, hydration, schedule adjustments, and training.

Guidance also covers targeted outreach to older adults and other high-risk groups, planning for cooling shelters and shaded public spaces, and coordination among health, emergency, and urban agencies to ensure timely, consistent responses.

Results and key findings

• China: In Guangzhou, both maximum and minimum temperatures were significantly associated with work‑related injuries in warm months. A companion analysis quantified the economic burden of heat‑related occupational injuries using workers’ compensation data.
• China: In Shenzhen, extreme heat was defined using the local 95th percentile daily mean temperature (30.2°C). Ambulance dispatches rose immediately on hot days, with the highest relative risks observed for urinary disease and elevated risks also seen for obstetric and gynecological, cardiovascular, respiratory, gastrointestinal, and mental and behavioral conditions.
• Thailand: National analyses across 60 provinces used 30 heatwave definitions grouped by intensity, then pooled the results to the national level. Cumulative effects on total and cause specific mortality were greater for low- and mid-intensity heatwaves than for the most intense category, and vulnerability was higher in Northern and Central regions, with older population share a key driver.
• Vietnam: In Ho Chi Minh City, the minimum‑mortality temperature was 29.4°C. Defined heatwaves in 2010 and 2013 coincided with higher daily deaths, while hospitalizations showed weaker responses. Heatwaves increased mortality, and significant hospitalization effects were confined to older people and those with respiratory disease.
• Across sites, time‑series models combined with locally relevant indices, such as apparent temperature, provided practical thresholds and inputs for heat‑health warning systems and for targeting protections to high‑risk groups.
• Numerous peer-reviewed publications resulted from this study. A full list is available on this page under “Project publications.”

Project details

Acknowledgements

This project was supported by the Asia-Pacific Network for Global Change Research (APN) under its Collaborative Regional Research Programme (CRRP). Acknowledgements also go to Sun Yat-sen University; Guangdong Provincial Center for Disease Control and Prevention (China); International Centre for Diarrhoeal Disease Research, Bangladesh; Ministry of Public Health (Thailand); Ministry of Health (Vietnam); Commonwealth Scientific and Industrial Research Organisation, (Australia); Griffith University (Australia); Queensland University of Technology (Australia).

Related information

• Project Permalink
• Project Final Report
• Li, C., Wang, Q., Bao, J., Zhao, Q., & Huang, C. (2017, September). Temperature variability may trigger spontaneous early delivery in Shenzhen, China: A case-crossover study. Oral presentation presented at the 29th Annual Scientific Conference of the International Society of Environmental Epidemiology, Sydney, Australia. Online abstract. https://www.apn-gcr.org/publication/temperature-variability-may-trigger-spontaneous-early-delivery-in-shenzhen-china-a-case-crossover-study/
• Sheng, R., Li, C., & Huang, C. (2017). 0106 Association between high temperature and work-related injuries in Guangzhou, China. Oral Presentation. doi:10.1136/oemed-2017-104636.80. https://www.apn-gcr.org/publication/association-between-high-temperature-and-work-related-injuries-in-guangzhou-china/
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