Early-life exposure to air and noise pollution is associated with a higher risk for psychosis, depression, and anxiety in adolescence and early adulthood, results from a longitudinal birth cohort study showed.
While air pollution was associated primarily with psychotic experiences and depression, noise pollution was more likely to be associated with anxiety in adolescence and early adulthood.
“Early-life exposure could be detrimental to mental health given the extensive brain development and epigenetic processes that occur in utero and during infancy,” the researchers, led by Joanne Newbury, PhD, of Bristol Medical School, University of Bristol, England, wrote, adding that “the results of this cohort study provide novel evidence that early-life exposure to particulate matter is prospectively associated with the development of psychotic experiences and depression in youth.”
The findings were published online on May 28 in JAMA Network Open.
Large, Longitudinal Study
To learn more about how air and noise pollution may affect the brain from an early age, the investigators used data from the Avon Longitudinal Study of Parents and Children, an ongoing longitudinal birth cohort capturing data on new births in Southwest England from 1991 to 1992.
Investigators captured levels of air pollutants, which included nitrogen dioxide and fine particulate matter with a diameter smaller than 2.5 µm (PM2.5), in the areas where expectant mothers lived and where their children lived until age 12.
They also collected decibel levels of noise pollution in neighborhoods where expectant mothers and their children lived.
Participants were assessed for psychotic experiences, depression, and anxiety when they were 13, 18, and 24 years old.
Among the 9065 participants who had mental health data, 20% reported psychotic experiences, 11% reported depression, and 10% reported anxiety. About 60% of the participants had a family history of mental illness.
When they were age 13, 13.6% of participants reported psychotic experiences; 9.2% reported them at age 18, and 12.6% at age 24.
A lower number of participants reported feeling depressed and anxious at 13 years (5.6% for depression and 3.6% for anxiety) and 18 years (7.9% for depression and 5.7% for anxiety).
After adjusting for individual and family-level variables, including family psychiatric history, maternal social class, and neighborhood deprivation, elevated PM2.5 levels during pregnancy (P = .002) and childhood (P = .04) were associated with a significantly increased risk for psychotic experiences later in life. Pregnancy PM2.5 exposure was also associated with depression (P = .01).
Participants exposed to higher noise pollution in childhood and adolescence had an increased risk for anxiety (P = .03) as teenagers.
Vulnerability of the Developing Brain
The investigators noted that more information is needed to understand the underlying mechanisms behind these associations but noted that early-life exposure could be detrimental to mental health given “extensive brain development and epigenetic processes that occur in utero.”
They also noted that air pollution could lead to restricted fetal growth and premature birth, both of which are risk factors for psychopathology.
Martin Clift, PhD, of Swansea University in Swansea, Wales, who was not involved in the study, said that the paper highlights the need for more consideration of health consequences related to these exposures.
“As noted by the authors, this is an area that has received a lot of recent attention, yet there remains a large void of knowledge,” Dr. Clift said in a UK Science Media Centre release. “It highlights that some of the most dominant air pollutants can impact different mental health diagnoses, but that time-of-life is particularly important as to how each individual air pollutant may impact this diagnosis.”
Study limitations included limitations to generalizability of the data — the families in the study were more affluent and less diverse than the UK population overall.
The study was funded by the UK Medical Research Council, Wellcome Trust, and University of Bristol. Disclosures were noted in the original article.
A version of this article appeared on Medscape.com.