Researchers from the Case Western Reserve University School of Medicine concluded that exposure to chemicals found in common household items ranging from hand sanitizer and hair spray to furniture and electronics may be linked to various neurological diseases.
The study, published March 25 in the Nature Neuroscience journal, concluded that groups of chemicals, organophosphate flame retardants and quaternary ammonium compounds, which are found in many household items, harm specialized cells that generate protective insulation around nerve cells in the brain. Loss of these cells, known as oligodendrocytes, has been associated with certain neurological issues, said Erin Cohn, the study's lead author.
"We found that the chemicals were more specifically targeting this specific cell type (which) are the cells that are destroyed in neurological diseases like multiple sclerosis," she said.
Cohn added the study is the first to find a potential link between these chemicals and neurological diseases, and may help to explain the increased prevalence of certain neurological disorders in recent years.
“For certain conditions like autism or ADHD, you see that the incidence of these diseases is rising year by year," she said. "There are more cases reported, but that cannot be completely explained just by genetics.”
The increased use of sanitizers, which contain quaternary ammonium compounds, in the aftermath of the COVID-19 pandemic is a potential concern and one possible reason for the increase in neurological diseases, Cohn said. She added that studies undertaken since COVID-19 have shown increased levels of quaternary compounds in the blood of some humans.
Additionally, CWRU's own study found a potential link between exposure to organophosphate flame retardants and neurological issues, Cohn said.
"In children who have the high exposure levels, they were more likely to report having things like motor dysfunction and other abnormal measures of brain health," she said.
Cohn noted the concern is these chemicals are ubiquitous, making the potential risks significant.
"The chemicals that we identified, they're in products that are most likely found in every single household, so things that we're all continuously exposed to probably for long periods of time and, for the most part, we don't really know how they're affecting our health," she said.
Despite this, Cohn said the research has not progressed far enough to draw a direct connection between the presence of these chemicals and neurological disorders. Instead, it is meant to raise awareness of potential risks as the study's principal investigator, Dr. Paul Tesar, director of the Institute for Glial Sciences at the medical school, and his team move the research forward.
"We need to think about our increased use of these chemicals," Cohn said. "For that one type of chemical, we dramatically increased our use of it during and maybe even after the COVID-19 pandemic. I think that we just need to consider how we're using these chemicals, whether or not we're increasingly exposed, so we can sort of just be in a better position as a society, to know that we're not putting ourselves or our kids at risk."
Looking ahead, future studies need to determine who is exposed to these chemicals, when these exposures happen and how long they occur to connect exposure to neurological issues, Cohn said.
"In order to draw these really direct connections, there needs to be future studies looking more in depth at human exposure and multiple measures of abnormal brain health," she said.
Future studies could also include direct assessment of the brain using magnetic resonance imaging (MRI) to better determine whether exposures cause any sort of abnormal changes in brain structure, Cohn said.
She said CWRU is interested in moving this research forward. However, since the medical school mostly does lab research, the next steps may involve collaboration with clinicians at University Hospitals to better understand the impact of exposure to these chemicals on children and adults, Cohn said.
"We're definitely going to keep pursuing these chemicals because we want to get the full picture," she said. "We want to be able to draw those direct connections and I think we can do that, not just in the laboratory, but also through collaborations with clinicians."
Cohn added Tesar has begun to reach out to University Hospitals about this next step, but nothing has been formalized yet.
