Study examines high temperatures, hospitalizations

Like Arizona, summer weather in Brisbane, Australia can get hot. Dangerously hot. And on the most extreme days, hospitalizations go up for residents of certain parts of the city, but not others. The question is why?

That’s something David Hondula is trying to answer. Hondula is a researcher in the Center for Policy Informatics in the College of Public Programs at Arizona State University.

“We know that heat is the leading weather-related cause of death in many cities around the globe,” says Hondula. “This despite the fact these deaths and heat-related illnesses are believed to be completely preventable with relatively simple intervention measures.”

Hondula teamed with Adrian Barnett, an associate professor in the School of Public Health and Social Work and the Institute for Heath and Biomedical Innovation at Queensland University of Technology in Brisbane. They examined five years of emergency room admissions data and compared results to daily temperature changes in Brisbane. The researchers excluded hospital admissions for such things as car crashes, accidents and medical complications.

“We wanted to know where in Brisbane the impacts are most severe,” Hondula says, “and what the characteristics of those places are to inform the types of intervention strategies that might be most successful in reducing unwanted outcomes.”

Hondula and Barnett found that a 10 degree Celsius increase (18 degrees Fahrenheit) in temperature during the summer was associated with a 7.2-percent increase in hospital admissions the following day across the entire city. Examining the data more closely, they found that in only 16 of the city’s 158 areas studied, the relationship between high temperature and hospitalization was significant. Their findings will be published online May 1 in Environmental Health Perspectives, a science journal that explores the interrelationships between the environment and human health.

“The two suburb characteristics that we found to predict a high risk were a lack of high earners and higher population density,” says Barnett. “The link with earnings is most likely because of air conditioning. And high density areas tend to get hotter because of the lack of breezes.”

That’s because high-rise buildings can block breezes creating higher temperatures for those who live in the area. Air conditioning is a luxury few people on limited incomes can afford.

“Air conditioning is the most effective way of reducing your risk of heat-related illness, but it is expensive to install and run,” Barnett says. “Good urban planning can also improve our health during extreme heat.”

The researchers believe one solution could be for governments to introduce electicity subsidies during extreme heat to encourage vulnerable people to use their air conditioners. The U.K. uses a similar scheme to encourage people to use heating during extreme cold periods. Adopting building practices that reduce the heat island effect is another option. And incorporating more solar-powered air conditioning could generate much needed cooling while avoiding overloads to the electricity grid on hot days.

Implications of the study are not limited to Brisbane. The results can help other cities deal with heat-related hospitalizations and deaths.

“Advances in data and computing have made it possible to deliver information to public health officials and emergency managers to address health risks from environmental hazards,” says Hondula. “Here, we can see where intervention measures for extreme heat have not yet fully succeeded. and where limited public resources would be best directred to better protect the public."

Hondula began work on the study as a doctoral student at the University of Virginia and finished the study as a postdoctoral fellow in health informatics at ASU. The study was made possible by a Science to Achieve Results Graduate Research Fellowship from the U.S. Environmental Protection Agency and an East Asia and Pacific Summer Institutes Program collaborative grant funded by the Australian Academy of Science and the United States National Science Foundation. Hondula's ongoing work in this area is support by the Piper Health Policy Informatics initiative at ASU.

Media contact:

Paul Atkinson, paul.atkinson@asu.edu
ASU College of Public Programs
+1 602 496 0001

Kate Haggman, kate.haggman@qut.edu.au
Queensland University of Technology
+61 7 3138 0358