High Pollen Counts Linked to Increased Risk of Suicide

High pollen counts — which trigger uncomfortable, and at times, unbearable seasonal allergies — have been linked to suicides in up to 1,200 people annually.

“A small shock could have a big effect if you’re already in a vulnerable state,” said Joelle Abramowitz, associate research scientist at the University of Michigan’s Institute for Social Research, said in a press release from the school. “We looked specifically at pollen from all different kinds of plants, including trees, weeds and grasses.”

“Pollen allergies diminish cognitive function and disrupt sleep—predictors of suicidality,” the study, published in the Journal of Health Economics, says. The research noted “meaningful changes to suicides at higher levels of airborne pollen. Specifically, we find up to a 7.4% increase in suicides when pollen levels are in the top quartile.”

Symptoms of a pollen allergy range from runny, itchy eyes, to congestion, the Asthma and Allergy Foundation of America says, adding that for those with asthma, pollen can trigger wheezing and struggles with breathing.

And pollen counts are getting worse. “Climate warming and increased CO2 levels favor pollen seasons that start earlier,” Dr. Christina Ciaccio, chief of pediatric allergy and immunology at University of Chicago Medical Center, previously told PEOPLE. “And it’s more potent pollen. It seems to be more activating to our immune system.”

The study compared pollen counts with data from the National Violent Death Reporting System between 2006 and 2018, a period when there were nearly 500,000 suicides in the U.S. “Based on our incremental data, we estimate that pollen may have been a contributing factor in up to 12,000 of those deaths over the period, or roughly 900 to 1,200 deaths per year,” Abramowitz said in the release.

Seasonal allergies have been linked to a worsening of mood disorders, anxiety and depression, The New York Times reported. Dr. Todd Gould, a professor of psychiatry at the University of Maryland School of Medicine told the outlet that when your body attempts to fight inflammation, it releases cytokines, which “activate areas of the brain that regulate depression and anxiety.”

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The University of Michigan study found that the worse the pollen, the greater the risk for suicide. Researchers divided pollen levels into four tiers and found the suicide risk rose with each group. It increased 4.5% in the second level, 5.5% in the third and hit 7.4% in last category.

“We should be more conscious of our responsiveness to small environmental changes, such as pollen, and our mental health in general,” Abramowitz said. “Given our findings, I believe medical providers should be aware of a patient’s allergy history, as other research has also established a connection between allergies and a higher risk for suicide. I hope this research can lead to more tailored care and, ultimately, save lives.”

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