People who grow up in areas with poor air quality are more likely to develop depression and bipolar disorder in later life, according to a new study.
The study led by the University of Chicago and based on analysis of large population data sets from the United States and Denmark suggests a 'significant link' between pollution and mental health disorders in the countries.
Researchers used a US health insurance database of 151 million people with 11 years of inpatient and outpatient claims for neuropsychiatric diseases.
The study, published in PloS Biology, is the latest to link poor air quality with ill-health.
It was discovered that counties with the worst air quality had a 27% increase in bipolar disorder and a 6% increase in major depression compared with those with the best air quality.
They then compared the 'geo-incidents' of claims to measurements of 87 potential air pollutants.
To validate the findings, the UChicago team applied the same methodology to data from Denmark.
In collaboration with Denmark-based researchers Aarhus, they examined the incidence of neuropsychiatric disease in Danish adults living in areas with poor environmental quality up to their 10th birthdays.
The team found there was a 29% increase in mental health disorders for people living in counties with the worst air quality.
They also discovered by using the Danish data that early childhood exposure correlated even more strongly with major depression, schizophrenia, and personality disorders over inpiduals who grew up in areas with the highest quality air.
'Our studies in the United States and Denmark show that living in polluted areas, especially early in life, is predictive of mental disorders,' said computational biologist Atif Khan, first author of the study.
Dr. Daniel Maughan, an associate registrar for sustainability at the Royal College of Psychiatrists, said: “the study built on the 'increasing evidence' of a link between air pollution and the development of mental illness.”
“While the study does not show that air pollution causes mental illness, it 'suggests' a 'strong link' exists between early exposure and an increased risk of developing mental ill-health,” Dr. Maughan added.
“However, there are many environmental factors which could contribute to poor mental health for those people living in areas of high pollution - such as population density and diminished access to green spaces - so it is, therefore, difficult to isolate poor air quality as the cause of mental illness,”
World Health Organization (WHO) estimated that around seven million people die every year from exposure to fine particles in polluted air that lead to diseases such as stroke, heart disease, lung cancer, chronic obstructive pulmonary diseases and respiratory infections, including pneumonia.