Abstracts: ISEE 22nd Annual Conference, Seoul, Korea, 28 August-1 September 2010: Climate Change and Environmental Health
Although many studies have noted the association between high ambient temperatures and increases in hospital admissions and mortalities, relatively few have investigated the effect on ambulance services, a useful supplement to other morbidity data. The aim of this study was to investigate the effect of heatwaves on ambulance callouts and to identify heat-susceptible areas of the city of Adelaide, South Australia.
Ambulance service data and meteorological data relevant to the metropolitan area were obtained for the period between 1 July 1993 and 30 June 2005. Heatwaves in the warm season (October to March) were defined as being 3 or more consecutive days when daily maximum temperatures reached or exceeded 35°C. Statistical analysis of callouts was undertaken by comparing heatwave to non-heatwave periods using negative binomial regression accounting for overdispersion and long-term trends. Using destination postcodes of callouts, spatial epidemiological techniques investigated place-based risk. Exposure analysis was undertaken by determining threshold temperatures using non-linear least squares estimation.
Ambulance callouts increased by 3.6% during heatwaves compared to non-heatwave periods in the warm season, with an increase of 2.6 callouts per 1 degree C increase in daily maximum temperature above a threshold of 34.6°C. Industrial suburbs and those with a high proportion of low income families were identified as heat-sensitive regions of the metropolitan area. Cause-specific attendances varied between suburbs with some recording an increase of more than three-fold in work-related callouts during heatwaves.
In the absence of population adaptation to warmer summers, ambulance and other emergency services may be in greater demand should heatwaves become more frequent and intense with a changing climate. Strategies required to mitigate the negative health effects of extreme heat may need to be targeted towards susceptible sub populations, communities art risk, and industrial workplaces.