Study links air pollution to suicide in Utah
Utah lies in a region of the Unites States dubbed the "suicide belt", where rates are higher than in the rest of the country.
The state has topped the country in a depression index, recently devised by Perry Renshaw, a professor of psychiatry at the University of Utah.
Paradoxically, it has also topped surveys as the "happiest state" in the Union, with job satisfaction among the highest in the US.
Now scientists think they may have found an explanation in the affects of pollution, which is very high in the state's capital and most populous city.
The topography of Salt Lake City makes it prone to temperature inversion, which traps pollution close to the ground for extended periods.
Stephanie Pappas at Live Science has the details:
The research took place in Utah, part of the United States' western "suicide belt." Suicide is the 10th-leading cause of death in the United States; in Utah, it is the eighth. Though the notion that suicide and air quality could be linked may not seem intuitive, similar studies in South Korea, Taiwan and Canada have also linked the two.
Altogether, the findings suggest that suicide "is a preventable outcome, and air pollution could be a modifiable risk factor," said Amanda Bakian, an epidemiologist at the University of Utah and the leader of the new study.
The possibility of environmental triggers for suicide has been raised before.
A 2010 study in the American Journal of Psychiatry linked suicide with increases in particulate matter in the air in Korea; 2011 research in the Journal of Affective Disorders made the same link in Taiwan. Another 2010 study, this one in Vancouver, found that wintertime emergency room visits for suicide attempts increased in the days following high air pollution levels.
The suggestion is that physical inflammation might be to blame, when the immune system goes into overdrive.
The inflammatory compound quinolinic acid has been directly linked to suicidal thoughts, and research has further connected suicide rates with the level of inflammation-promoting particles in the air. For example, a 2013 study published in the journal BMJ Open found that suicides in Denmark went up with tree pollen levels.