Short-term exposure to air pollution may aggravate autism symptoms in children, increasing the risk of hospitalisation, according to new research published in BMJ Open.
The study’s results suggest that reducing air pollution exposure could be used as a method to help control and manage autism symptoms, including hyperactivity, aggression and self-injury, which are common reasons for hospitalisation.
The link between autism and neuroinflammation
Autism is often accompanied by neuroinflammation, and since exposure to air pollution can induce systemic inflammation and neuroinflammation, the researchers wanted to see find out if short-term exposure to air pollution aggravated autism symptoms in school-aged children.
The researchers focused on children because a child’s developing nervous system is more susceptible to environmental exposures than an adult’s.
To conduct the research, they used official data from the Korean government on daily hospital admissions for autism among children aged 5 to 14 between 2011 and 2015.
They also looked at the national daily levels of air pollution in each of the 16 regions in the Republic of Korea for up to six days, looking particularly at levels of fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3).
Boys at greater risk of hospitalisation for autism compared to girls
The average daily number of hospital admissions for autism during the study period was 8.5 for autistic children and was much higher for boys (7) than for girls (1.6).
The results showed that short-term exposure to PM2.5, NO2, and O3 was associated with a heightened risk of hospital admission for autism and boys were at greater risk of hospital admission for autism compared to girls.
The researchers calculated that exposure to these pollutants was associated with a one-quartile increase, which corresponds to a 29% higher risk of hospital admission for autism, with nitrogen dioxide exerting the strongest effects.
Reduction of air pollution exposure should be considered for autism symptom management
It is important to note that the results of the study are based on regional air pollution levels rather than individual ones, so this could have affected the findings.
Additionally, autistic children with mild symptoms might be less likely to receive psychiatric treatment and so might not have been included.
Despite this, the authors say the study’s results suggest that short-term exposure to air pollution affects autism symptom aggravation.
“These results emphasise that reduction of air pollution exposure should be considered for ASD symptom management, with important implications for the quality of life and economic costs,” they conclude.