Feb. 20, 2009 -- There’s now another reason to be concerned about global warming. A new study shows that when temperatures rise in the summer, there are more hospitalizations for respiratory problems, especially among elderly people.
The data come from a European project called the "Assessment and Prevention of Acute Health Effects of Weather Conditions in Europe". The study was a collaborative effort between epidemiologists, meteorologists, and experts in public health.
For the study, researchers looked at data from at least a three-year period for 12 European cities: Barcelona, Budapest, Dublin, Ljubljana, London, Milan, Paris, Rome, Stockholm, Turin, Valencia, and Zurich. All data were collected between 1990 and 2001. Researchers tracked temperatures as well hospitalizations with a focus on the warmest part of the year from April to September. They examined hospitalization rates for all ages, as well as for two subgroups -- ages 65-74 and 75-plus.
In the 75-plus crowd, respiratory hospitalizations increased 4.5% for every 1 degree Celsius the temperature climbed over the maximum apparent temperature at the time in cities in the Mediterranean region and 3.1% for every degree in cities in the North-Continental region. The maximum apparent temperature took into account the effect of temperature and humidity.
No association was seen between temperature and cardiovascular and cerebrovascular hospitalizations.
The regional differences could be a result of many factors, according to author Paola Michelozzi, PhD, head of environmental epidemiology at the department of epidemiology of the local health authority in Rome.
“This is in part due to differences in exposure, the large variability among the cities analyzed, the differences in adaptive capacity and the vulnerability of populations due to their socio-demographic characteristics, as well as differences in the preventive measures in place,” Michelozzi says in a written statement. “Moreover, across European countries there is wide variation in healthcare and hospital admissions availability.”
In the study’s conclusion, authors call for an increased public health focus on preventing heat-related respiratory problems -- especially since such problems are likely to become more widespread with global warming. “Under climate change scenarios, the increase in extreme weather events and certain air pollutants, especially ozone, are likely to further aggravate chronic respiratory diseases,” the study says. “Public health interventions should be directed at preventing this additional burden of disease during the summer season.”