A new study suggests that children who have been exposed to higher levels of vehicle emissions were more likely to receive prescriptions for psychiatric disorders.
"There may be a link between exposure to air pollution and dispensed medications for certain psychiatric disorders in children and adolescents even at the relatively low levels of air pollution in the study regions," concluded researchers from UmeÃ¥ University in Sweden
Performed by researchers at Umea University in Sweden, the study looked at the national register of prescriptions for 552,221 children and adolescents under the age of 18 in four Swedish counties between 2007 and 2010. This information was then compared with measured concentrations of particulates and nitrogen dioxide, a byproduct of vehicle combustion, found in the neighborhoods of the children involved.
Investigators found that for every 10 micrograms per cubic meter of nitrogen dioxide, the chances of children being prescribed a medication for at least one psychiatric disorder increased by 9%. Prescribed drugs included antipsychotic medications, sedatives, and sleeping pills. The risk continued even after socioeconomic and demographic factors were controlled for, reports David Kirby for TakeApart.
"This is a very broad or crude marker of mental health," said lead author Anna Oudin, a researcher in the Department of Public Health and Clinical Medicine at UmeÃ¥ University. "We can't say if one of the medications in that group drove the association of all of them, but it's sort of a hint that there's something there."
Prescription records did not include antidepressants or drugs meant to treat attention deficit hyperactivity disorder. Oudin said this is because they used data that was readily available to the public, and are currently applying for permission from the authorities for information pertaining to other drugs.
Previous studies on the topic have concluded that a connection exists between air pollution and mental health in adults, including depression, anxiety, and stress. Meanwhile, studies concerning children have found an association between cognitive disabilities and disorders like autism.
Although air pollution is more commonly found in urban areas, researchers for the study did not conclude that such areas were more likely to cause mental disorders. While three of the counties looked at are highly populated, the fourth is mostly rural.
"The fact that we found this effect in low-density areas doesn't support the idea that this is due to an urban environment," Oudin said.
Meanwhile, a sub-analysis performed on children who live in urban areas found a connection between high nitrogen dioxide levels and drug prescriptions, which researchers say could mean that pollution is the contributing factor rather than city life. Oudin added that data was not available on traffic-related noises or access to green environments, which she said could be an explanation.
Michelle Block, an associate professor of anatomy and cell biology at Indiana University, said the study findings agree with what she has seen in the lab in her studies of how pollution, which is made up of toxic gases, metals, and other compounds, impacts the immune cells of the brain. She added that the study is important and that she expects to see further research being conducted on the subject.