Heatwave and risk of heat-related burn injury in children in Western Australia

To the Editor: Hot weather causes heat exhaustion, sunburn and contact burns. Each summer, children with these injuries attend Princess Margaret Hospital for Children in Western Australia. The Commonwealth Scientific and Industrial Research Organisation has recently proposed a definition for heatwave, requiring 3 days or more of high maximum and minimum temperatures that are unusual for a specific location.1 This is based on an excessive heat index numerical prediction model2 that is being tested by the Bureau of Meteorology for heatwave forecasting.3 Are local weather observations associated with an increase in these types of hot weather-related injury in children?

Data on heat-related injury were collected about severity, type, date, time and place of injury, and age and sex of the victim. Local weather readings were obtained from the Bureau of Meteorology for minimum, maximum and average daily temperatures (ADT) in degrees Celsius and for solar exposure in megajoules per square metre (MJ/m2). We calculated excess heat using the sum of the ADT for the day of injury and the previous 2 days divided by three. Data were analysed by Poisson regression with STATA, version 12 (StataCorp). All models were adjusted for the summer period in each year, but this was not significant. No other adjustments were made.

Fifty-four children aged between 3 weeks and 15 years presented to Princess Margaret Hospital for Children with sunburn, contact burn or heat exhaustion in the 3-year period 1 January 2011 to 31 December 2013. There was a non-significant increase in the number of days in which heat-related injuries presented over this time. All three types of hot weather injury were associated with solar exposure recordings and with excess heat calculations. For every unit rise in solar exposure, there were 18% more sunburn presentations, 14% more contact burn presentations, and 16% more heat exhaustion presentations. For every unit rise in excess heat, we saw 11% more cases of sunburn, 26% more cases of contact burns and 9% more cases of heat exhaustion. Each of these results were statistically significant (Box).

The statistically significant association between hot weather recordings and these injuries means that heatwave forecasts in Perth could also predict an increased risk of these injuries, and thus could be used to trigger media messages about burn prevention to raise community awareness. As heatwave forecasting is location-specific, our findings might not be transferrable to other locations.