Respiratory hospitalizations among seniors increased 4.3% for each 10-degree increase in daily average summer temperature, according to results of a study.
This association, which was not changed by adjustments for air pollution, age, gender or seasonal trends in hospitalization rates and temperature, was strongest on the day of exposure to heat and remained elevated the day following exposure, researchers reported in the American Journal of Respiratory and Critical Care Medicine, a publication of the American Thoracic Society.
Researchers with the Johns Hopkins Bloomberg School of Public Health conducted an epidemiological study of more than 12.5 million Medicare beneficiaries. While outdoor heat has been shown to increase respiratory mortality, evidence on the relationship between heat and respiratory hospitalizations has been less consistent, G. Brooke Anderson, PhD, the studys lead author, said in a news release.
In the largest population of the elderly yet studied, we found strong evidence that short-term exposure to outdoor heat increases the risk of hospitalization for COPD and respiratory tract infections. This relationship was consistent for men and women and across all age groups.
The study included 213 urban counties across the United States and more than 30% of the U.S. population ages 65 and older. Data on Medicare emergency respiratory hospitalizations were obtained for the period 1999-2008, along with measurements of weather and air pollution.
The increased risk for heat-related hospitalization was similar for COPD (4.7%) and respiratory tract infections (4.1%), and tended to be higher in counties where summers typically are mild.
Each 10-degree increase in daily temperature translated to approximately 30 excess respiratory hospitalizations per day among the elderly in the 213 counties studied, with larger increases in temperature expected to result in additional hospitalizations.
Our study provides clear and consistent evidence of a link between outdoor heat and hospitalization for respiratory disease in the elderly, Roger D. Peng, PhD, the studys senior author, said in the news release. As the prevalence of respiratory conditions and the age of the population continue to increase and global temperatures continue to rise as a result of climate change, the risk of heat-related respiratory disease is also likely to increase.