While we've always known that air pollution has presented various health risks such as cardiovascular disease and ischaemic heart disease, a new report is claiming there may also be a link to autism and schizophrenia resulting from exposure to air pollution.
This is now the second study in the last nine months claiming an epidemiological link between pollution and autism.
The most recent study was conducted by researchers from the University of Rochester. It claims to have uncovered what they are calling a biological mechanism that explains how exposure to air pollution is putting people at a higher risk for both autism and schizophrenia.
"From a toxicological point of view, most of the focus of air pollution research has been on the cardiopulmonary system -- the heart and lungs," the study's lead author Deborah Cory-Slechta, professor of environmental medicine at the University of Rochester, said. "But I think it's becoming increasingly clear that the adverse things happening there are also happening in the brain, and this may be adding to risks for neurodevelopmental disorders like autism that we hadn't thought about before."
The first study, published in JAMA Psychiatry in October of 2013, to make a connection between pollution and autism was conducted in September 2013 as researchers on this report found that children who lived in areas with high levels of traffic pollution seemed to be more likely to be diagnosed with the neurodevelopmental disorder.
The experiments in the more recent University of Rochester study were done using different groups of young lab mice. Air pollution contains carbon particles that are created when cars and power plants burn fuel, and the particles are measured in two sizes, large and ultra-fine. The test checked on the effects of ultra-fine particles that get into the lungs and then enter the bloodstream.
The groups of mice were exposed to levels of air pollution equivalent to those seen in rush hour traffic. The exposure was done twice, each time for four days. After four hours of exposure a day, researchers discovered that the mice exposed to the pollution showed significant changes in behavior compared with mice living in an environment with filtered air.
"We see changes in learning produced by these exposures in males and females, and in levels of activity, and we saw deficits in memory in both males and females," Cory-Slechta said. "We also had a measure of attention, looking at impulsive-like behaviors, which we only tested in males, and there, too, we saw the effects of postnatal exposure."
The study also discovered that the aforementioned results were long lasting -- researchers reported these behavioral differences seen between the two groups of mice were present up to 10 months after the pollution exposure. The study was published in the journal Environmental Heath Perspectives.
The connection to autism was seen in the fact the brains of the exposed mice suffered severe inflammation and enlargement of the ventricles, the chambers on either side of the brain that hold cerebrospinal fluid. The study explains that in humans, this condition can be symptomatic of a brain condition called ventriculomegaly, which is accompanied by varying degrees of neurodevelopmental impairment, similar to what is seen in cases of autism.