February 1, 2023

expert reaction to study on association between long-term air pollution exposure and risk of depression and anxiety

A study published in JAMA Psychiatry looks at long-term exposure to multiple ambient air pollutants, and depression and anxiety.

Prof Anna Hansell Professor of Environmental Epidemiology and Director of the Centre for Environmental Health and Sustainability, University of Leicester, said:

“This study provides further evidence on potential impacts of air pollution on the brain. The Committee on the Medical Effects of Air Pollution (COMEAP) reported in 2022 on the evidence of associations between air pollution and cognitive decline and dementia. The report concluded that the link was likely to be causal. However, there are few studies to date on air pollution and mental health. This well-conducted new study found associations between air pollution and anxiety and depression in the UK, which experiences lower air pollution than many countries worldwide.

“The study followed up 389,000 individuals in the UK over 10 years, taking account of factors such as deprivation and employment status that might also influence mental health. They found that air pollution concentrations at the place individuals lived when recruited into the study were associated with small increases in risk of subsequently developing clinical depression or anxiety. This was seen with combinations of air pollutants, as well as with specific components such as fine particulates and NO₂, where fossil fuel combustion (road transport) forms a major source. A particular strength of this epidemiological study is that it followed up individuals over a long period of time (10 years). Other types of studies investigating mechanisms are needed to help strengthen our understanding of how air pollution may affect the brain.

“The study findings suggest that reducing air pollution levels, even when low, potentially benefits mental health. It provides further evidence in support of reducing current UK air pollution levels.”

‘Long-term Exposure to Multiple Ambient Air Pollutants and Association With Incident Depression and Anxiety’ by Teng Yang et al. was published in JAMA Psychiatry at 16:00 UK time on Wednesday 1 February.

DOI: 10.1001/jamapsychiatry.2022.4812

Declared interests

Prof Anna Hansell is the chair of COMEAP, but these comments are made in a personal capacity as Professor of Environmental Epidemiology at the University of Leicester.