“There may be another risk factor out there that we were not aware of earlier,” said Amanda Bakian, the study’s author.
After tracking 10 years of suicides in Salt Lake County, Bakian, a psychiatry professor, found the odds of dying from suicide were 20 percent higher for those exposed to increased levels of particulates, specifically nitrogen dioxide or car exhaust, in the three days before their deaths.
Bakian broke the data into seasons. She says surprisingly the risk was highest not during the winter's inversions, but in fall and spring.
“Pollution may be interacting with other springtime risk factors for suicide, such as maybe allergies or pollen, which has also been associated for suicide or other medical or mood disorders,” said Bakian.
A study in Asia found similar results, but this is the first of its kind conducted in the U.S.
In Utah, it could be a breakthrough. The state is part of what's called the “suicide belt”. States with higher elevation have been linked to higher suicide rates. In both hypotheses, the air we breathe is a factor.
“This reduction of oxygen or oxidated stress,” said Bakian. “When it comes to air pollution we also hypothesize that it may be inflammation involved.”
While the study doesn't imply pollution causes suicide, suicide prevention advocates say it might interact with other factors to increase the risk, such as mental illness and substance abuse.
“If you take an individual at high risk and they already have other factors going on, this may add to their risk factors,” said Rebecca Glathar, executive director of NAMI Utah. “So it's something to pay attention to if you have an individual who is at high risk, then be watching.”
The research between air pollution and suicide will continue. Researchers are using University funding to try to find out more on why there is this correlation.
Bakian’s next study will look will at other factors such as genes and mental illness.