By Tracy Hampton, PhD, Beth Israel Deaconess Medical Center Correspondent
Growing evidence suggests that rising temperatures may make symptoms worse for patients with chronic obstructive pulmonary disease, or COPD, which refers to emphysema, chronic bronchitis, and other breathing difficulties. The group of diseases affects 15 million Americans, many of whom avoid activities that they used to enjoy because they become short of breath more easily.
Past studies have shown that bacterial or viral infections, such as a cold, as well as exposure to harmful pollutants can cause worsening of COPD symptoms. A new study, which was presented recently at the annual meeting of the American Thoracic Society and involved 84 former smokers with moderate to severe COPD, found that patients exposed to warmer temperatures indoors experienced a worsening of their symptoms and a decrease in lung function.
Warmer temperatures outside were also linked to an increase in COPD symptoms, but they did not affect lung function. Over the course of a nine-month period, participants were observed for one week every three months. Researchers measured their breathlessness, cough production, lung function, and their need for an inhaler, and recorded the daily outdoor temperature as well as the temperature inside their homes.
It was noted that during more than 600 days of monitoring during warm months, participants went outside on 48% of those days. Even after taking air pollution concentrations into account, warmer indoor temperatures were linked to a rise in symptoms, the need for medications, and a decline in lung function. Warmer outside temperatures were linked only with worsening of symptoms.
The findings lend support to earlier studies. For example, a study of New York City summers from 1991 to 2004 found that each 1°C above a certain threshold resulted in an increase in same-day hospitalizations for patients with respiratory diseases, especially COPD and asthma.
“Results from such studies indicate that efforts are needed to find ways to help COPD patients lessen their symptoms when temperatures rise,” says Sidhu Gangadharan, MD, chief of thoracic surgery at Beth Israel Deaconess Medical Center. “Understanding more about the impact of environmental factors such as air pollution or global warming on COPD and other respiratory diseases is crucially important.”
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Posted July 2014