Exposure to air pollution during early life may contribute to depression, anxiety, and other mental health problems in adolescence, three new studies suggest. A study, published in the journal Environmental Health Perspectives, found that short-term exposure to ambient air pollution was associated with exacerbations of psychiatric disorders in children one to two days later.
Researchers, including those from the University of Cincinnati in the US, also found that children living in disadvantaged neighbourhoods may be more susceptible to the effects of air pollution compared to other children, especially for disorders related to anxiety and suicidality.
"This study is the first to show an association between daily outdoor air pollution levels and increased symptoms of psychiatric disorders, like anxiety and suicidality, in children," said Cole Brokamp from Cincinnati Children's Hospital Medical Center.
"More research is needed to confirm these findings, but it could lead to new prevention strategies for children experiencing symptoms related to a psychiatric disorder," Brokamp said.
"The fact that children living in high poverty neighbourhoods experienced greater health effects of air pollution could mean that pollutant and neighbourhood stressors can have synergistic effects on psychiatric symptom severity and frequency," he said.
Two other Cincinnati Children's studies were recently published that also link air pollution to children's mental health, researchers said. A second study, published in the journal Environmental Research, found an association between recent high traffic related air pollution (TRAP) exposure and higher generalised anxiety.
The study is believed to be the first to use neuroimaging to link TRAP exposure, metabolic disturbances in the brain, and generalised anxiety symptoms among otherwise healthy children. Researchers, including Kelly Brunst from the University of Cincinnati, found higher myoinositol concentrations in the brain -- a marker of the brain's neuroinflammatory response to TRAP.
Another study, published in the journal Environmental Research, found that exposure to TRAP during early life and across childhood was significantly associated with self-reported depression and anxiety symptoms in 12 year olds.
Similar findings have been reported in adults, but research showing clear connections between TRAP exposure and mental health in children has been limited, according to Kimberly Yolton, director of research in the division of General and Community Pediatrics at Cincinnati Children's.
"Collectively, these studies contribute to the growing body of evidence that exposure to air pollution during early life and childhood may contribute to depression, anxiety, and other mental health problems in adolescence," said Patrick Ryan, a researcher at Cincinnati Children's.