Development of health risk-based metrics for defining a heatwave: a time series study in Brisbane, Australia.

Shilu Tong,Ken Verrall,Gerard Neville,Vivienne Tippett,Xiao Yu Wang,Peter Aitken,David Mcrae,Gerry Fitzgerald

doi:10.1186/1471-2458-14-435

Abstract

BackgroundThis study attempted to develop health risk-based metrics for defining a heatwave in Brisbane, Australia.MethodsPoisson generalised additive model was performed to assess the impact of heatwaves on mortality and emergency hospital admissions (EHAs) in Brisbane.ResultsIn general, the higher the intensity and the longer the duration of a heatwave, the greater the health impacts. There was no apparent difference in EHAs risk during different periods of a warm season. However, there was a greater risk for mortality in the 2nd half of a warm season than that in the 1st half. While elderly (≥75 years) were particularly vulnerable to both the EHA and mortality effects of a heatwave, the risk for EHAs also significantly increased for two other age groups (0 – 64 years and 65 – 74 years) during severe heatwaves. Different patterns between cardiorespiratory mortality and EHAs were observed. Based on these findings, we propose the use of a tiered heat warning system based on the health risk of heatwave.ConclusionsHealth risk-based metrics are a useful tool for the development of local heatwave definitions. This tool may have significant implications for the assessment of heatwave-related health consequences and development of heatwave response plans and implementation strategies.

Highlights

This study attempted to develop health risk-based metrics for defining a heatwave in Brisbane, Australia
The most severe heatwave occurred during 20 – 22 Feb. 2004, when three consecutive days with a mean temperature above 30°C were recorded in Brisbane
When investigating any difference in the heatwave effects between the early and late of warm season, we found that the impact of heatwaves on mortality and emergency hospital admissions (EHAs) seemed to be stronger in the second part of the warm season than the first (Table 5)

Summary

Introduction

This study attempted to develop health risk-based metrics for defining a heatwave in Brisbane, Australia. Evidence suggests that acclimatization, individual susceptibility, and community characteristics all affect heat-related effects on mortality [1]. This implies that it is difficult, if not impossible, to develop a universal definition of heatwave. Some efforts have been made to explore the best temperature predictor of mortality and an appropriate approach to develop a local definition of heatwave [15,17,18,19], but, few data are available on the use of health risk-based metrics in the development of a heatwave definition. This study attempted to develop health risk-based metrics to define a heatwave based on the estimation of its effects on mortality and emergency hospital admissions in Brisbane, Australia. We evaluated whether the effect estimates varied by heatwave characteristics (intensity, duration, and timing in season) and individual characteristics (age and disease category)

Methods

Results

Discussion

Conclusion