Antonella Zanobetti, Ph.D., Susan Redline, MD, MPH, Diane Gold, M.D., M.P.H. and colleagues explored the link between air pollution levels, temperature increases and sleep-disordered breathing using data from the Sleep Heart Health Study, which included more than 6,000 participants between 1995 and 1998, and EPA air pollution monitoring data from Framingham (Massachusetts), Minneapolis, New York City, Phoenix, Pittsburgh, Sacramento, and Tucson.
The study appears online ahead of the print edition of the American Journal of Respiratory and Critical Care Medicine on the American Thoracic Society's Web site.
SDB affects up to 17 percent of U.S. adults, many of whom are not aware that they have a problem. Air pollution is also an endemic issue in many of the nation's urban areas. Both SDB and pollution have been associated with a range of health problems, including increased cardiovascular mortality. "The influence of air pollution on SDB is poorly understood," said Dr. Zanobetti. "Our hypothesis was that elevation in ambient air pollution would be associated with an increased risk of SDB and nocturnal hypoxia, as well as with reduced sleep quality." The researchers further hypothesized that seasonal variations in temperature would exert an independent effect on SDB and sleep efficiency.
To test their hypotheses, the researchers used linear regression models that controlled for seasonality, mean temperature and other factors known to be associated with SDB, such as age, gender and smoking.
To examine the role of seasons, they performed a separate analysis, adding the interaction of season with the level of air pollution in the form of particulate matter under 10 ìm, which is commonly associated with traffic. They evaluated long-term effects by computing the moving 365-day average of PM10.
In total, they included more than 3,000 individuals in their analysis.
"We found novel evidence for pollution and temperature effects on sleep-disordered breathing," said Dr. Zanobetti. "Increases in apnea or hypopnea…were associated with increases in short-term temperature over all seasons, and with increases in particle pollution levels in the summer months."
Over all seasons, the researchers found that short-term elevations in temperature were associated with increased in Respiratory Disturbance Index (RDI), which was used to gauge the severity of SDB. In the summer, increases in PM10 were also associated with an increase in RDI (representing a 12.9 percent increase), as well as with an increase in the percent of time that blood oxygen saturation levels fell below 90 percent (representing a nearly 20 percent increase) and a decrease in sleep efficiency. There were no such statistically significant associations of particulate pollution with SDB in other seasons.
This is the first study to link pollution exposure and SDB.
"Particles may influence sleep through effects on the central nervous system, as well as the upper airways," wrote Dr. Zanobetti. "…Poor sleep [associated with poor health outcomes] may disproportionately afflict poor urban populations. Our findings suggest that one mechanism for poor sleep and sleep health disparities may relate to environmental pollution levels."
Other research has found an association between elevation in pollution and increased risk of sudden infant death syndrome (SIDS). There is a known overlap between etiologic factors for SIDS and SDB. Given the results of the current research, "the mechanisms that increase the risk of SIDS in associations with ambient pollutants may be similar to the mechanisms that underlie the risk of SDB…,[which] may include pollutant-associated effects on central or peripheral neurotransmitters that influence sleep-state stability," said Dr. Zanobetti.
Several studies have also reported that temperature predicts mortality. "The association we found between short-term temperature and RDI could represent one possible mechanism by which changes across the range of temperature could predict mortality," said Dr. Zanobetti.
Perhaps most importantly, the prevalence of SDB in the United States may increase as obesity rises. "While therapies are available for the disorder, the majority of adults with SDB are not being treated and many people are resistant to therapy," said Dr. Zanobetti. "Along with reduction in obesity, these new data suggest that reduction in air pollution exposure might decrease severity of SDB and nocturnal hypoxia and may improve cardiac risk."
John Heffner, M.D., past president of the American Thoracic Society observed, "This study gains even greater importance as scientists increasingly demonstrate the critical importance of sleep to health and well being. SDB increases risks for cardiovascular disease, strokes and other major health conditions. Air pollution is an independent contributor to most of these disorders and may produce its negative health effects by promoting SDB as an intermediary step in the pathway toward disease."
This study was funded by the National Heart Lung and Blood Institute, the National Institute of Environmental Health Sciences and the Environmental Protection Agency.
Link to podcast: http://www.thoracic.org/newsroom/press-releases/journal/podcast/061510-zanobetti.mp3
Keely Savoie | EurekAlert!
Investigators may unlock mystery of how staph cells dodge the body's immune system
22.09.2017 | Cedars-Sinai Medical Center
Monitoring the heart's mitochondria to predict cardiac arrest?
21.09.2017 | Boston Children's Hospital
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy