WEDNESDAY, June 16 (HealthDay News) -- A new study has found a
link between air pollution and breathing-related disruptions during
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-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
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
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
For more about sleep apnea, try the
U.S. National Library of Medicine.