WEDNESDAY, June 16 (HealthDay News) -- A new study has found a link between air pollution and breathing-related disruptions during sleep.
Conducted by the Harvard School of Public Health and Brigham & Women's Hospital, the authors say this the first attempt to document a link between exposure to pollution and sleep-disordered breathing.
Breathing-related sleep disruptions come in several forms, of which the best known is sleep apnea. It causes people to repeatedly wake up when their airways constrict and breathing is cut off. In many cases, sufferers don't realize they have the condition, which can contribute to the development of heart disease and stroke.
In the study, researchers tried to discover if air pollution -- which irritates the airways -- has anything to do with sleep disruptions, which affect an estimated 17 percent of adults in the United States.
The study authors pored over data from the Sleep Heart Health Study, which examined the heart health and sleep patterns of more than 6,000 people between 1995 and 1998. They then compared those patterns to Environmental Protection Agency (EPA) air pollution data on seven cities: Minneapolis; New York City; Phoenix; Pittsburgh; Sacramento; Tucson, Ariz.; and Framingham, Mass.
The researchers analyzed data on more than 3,000 people and adjusted for factors such as age, gender, smoking and temperature so they wouldn't throw off the results.
They found that incidents of sleep apnea and low levels of oxygen during sleep went up as the temperature rose during all seasons of the year. Sleep-disordered breathing also rose during the summer as air pollution worsened.
Particles of pollution "may influence sleep through effects on the central nervous system, as well as the upper airways," wrote co-author Antonella Zanobetti in a news release, noting that the exact mechanism is unclear. "These new data suggest that reduction in air pollution exposure might decrease the severity of such sleep disruptions."
The study, funded by the U.S. National Heart Lung and Blood Institute, the EPA and the U.S. National Institute of Environmental Health Sciences, appeared online June 14 in the American Journal of Respiratory and Critical Care Medicine.
For more about sleep apnea, try the U.S. National Library of Medicine.