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Abstract: Adelaide experienced an extreme and prolonged 13days heatwave in summer 2009. The health impacts of this heatwave included an almost 14-fold increase in direct heat-related hospital admissions. This study aims to investigate the risk factors for this extra health burden. A case crossover study was conducted in metropolitan Adelaide to compare the characteristics of patients from the heatwave (exposure) period and non-heatwave (control) periods before and after. Direct heat-related hospitalizations were identified based on the ICD-10 codes (X30, T67, and E86). Patients'' data, including age, gender, indicators of health status, living conditions and socio-economic status, were collected from the South Australian Department of Health and patients'' case-notes from seven major Adelaide hospitals. Multivariate logistic regression model was used to estimate the odd ratios (OR) and the 95% confidence intervals (CI). Results indicate that living at residential aged care (OR=0.41, 95% CI: 0.15–0.70) and having higher number of co-morbidities (OR=0.89, 95% CI: 0.83–0.95) reduced the risk of hospital admission for direct heat-related illnesses during the heatwave, while having renal problems (OR=1.72, 95% CI: 1.07–2.94), reporting a fall prior to hospitalization (OR=2.04, 95% CI: 1.10–3.77), receiving assistance from community (OR=2.31, 95% CI: 1.24–4.30), living alone (OR=2.41, 95% CI: 1.32–4.40), socio-economic disadvantage (OR=2.10, 95% CI: 1.09–4.04) and no private health insurance (OR=1.82, 95% CI: 1.05–3.16) increased the risk. In conclusion, the people most at risk during the 2009 heatwave in Adelaide were those who lived alone, received help from community services, with co-existing renal problems or a risk of falls, and with a lower socio-economic status. Findings will assist in refining heat-health response systems and developing intervention programmes. [Copyright &y& Elsevier]

Abstract: Background: Climate change projections have highlighted the need for public health planning for extreme heat. In Adelaide, South Australia, hot weather is characteristic of summer and heatwaves can have a significant health burden. This study examines the heat thresholds and temperature relationships for mortality and morbidity outcomes in Adelaide. Methods: Daily maximum and minimum temperatures, daily mortality, ambulance call-outs, emergency department (ED) presentations and hospital admissions were obtained for Adelaide, between 1993 and 2009. Heat thresholds for health outcomes were estimated using an observed/expected analysis. Generalized estimating equations were used to estimate the percentage increase in mortality and morbidity outcomes above the threshold temperatures, with adjustment for the effects of ozone (O3) and particulate matter<10μm in mass median aerodynamic diameter (PM10). Effect estimates are reported as incidence rate ratios (IRRs). Results: Heat-related mortality and morbidity become apparent above maximum and minimum temperature thresholds of 30°C and 16°C for mortality; 26°C and 18°C for ambulance call-outs; and 34°C and 22°C for heat-related ED presentations. Most health outcomes showed a positive relationship with daily temperatures over thresholds. When adjusted for air pollutants, a 10°C increase in maximum temperature was associated with a 4.9% increase in daily ambulance call-outs (IRR 1.049; 95% CI 1.027–1.072), and a 3.4% increase in mental health related hospital admissions (IRR 1.034; 95% CI 1.009–1.059) for the all-age population. Heat-related ED presentations increased over 6-fold per 10°C increase in maximum temperature. Daily temperatures were also associated with all-cause and mental health related ED presentations. Associations between temperature over thresholds and daily mortality and renal hospital admissions were not significant when adjusted for ozone and PM10; however at extreme temperatures mortality increased significantly with increasing heat duration. Conclusions: Heat-attributable mortality and morbidity are associated with elevated summer temperatures in Adelaide, particularly ambulance call-outs, mental health and heat-related illness. [Copyright &y& Elsevier]