Heatwave and work-related injuries and illnesses in Adelaide, Australia: a case-crossover analysis using the Excess Heat Factor (EHF) as a universal heatwave index.

Purpose: Heatwaves, or extended periods of extreme heat, are predicted to increase in frequency, intensity and duration with climate change, but their impact on occupational injury has not been extensively studied. We examined the relationship between heatwaves of varying severity and work-related injuries and illnesses. We used a newly proposed metric of heatwave severity, the Excess Heat Factor (EHF), which accounts for local climate characteristics and acclimatization and compared it with heatwaves defined by daily maximum temperature.

Methods: Work-related injuries and illnesses were identified from two administrative data sources: workers' compensation claims and work-related ambulance call-outs for the years 2003-2013 in Adelaide, Australia. The EHF metrics were obtained from the Australian Bureau of Meteorology. A time-stratified case-crossover regression model was used to examine associations between heatwaves of three levels of severity, workers' compensation claims, and work-related ambulance call-outs.

Results: There was an increase in work-related ambulance call-outs and compensation claims during low and moderately severe heatwaves as defined using the EHF, and a non-significant decline during high-severity heatwaves. Positive associations were observed during moderate heatwaves in compensation claims made by new workers (RR 1.31, 95% CI 1.10-1.55), workers in medium-sized enterprises (RR 1.15, 95% CI 1.01-1.30), indoor industries (RR 1.09, 95% CI 1.01-1.17), males (RR 1.13, 95% CI 1.03-1.23) and laborers (RR 1.21, 95% CI 1.04-1.39).

Conclusions: Workers should adopt appropriate precautions during moderately severe heatwaves, when the risks of work-related injuries and illnesses are increased. Workplace policies and guidelines need to consider the health and safety of workers during heatwaves with relevant prevention and adaptation measures.