Air pollution can increase risk of suicidal behaviour, says study

Dand according to a meta-analysis published in the Journal of Epidemiology & Community Health, exposure to air pollutants, especially to fine particles and nitrogen dioxide, significantly increases suicidal thoughts and the risk of death by suicide.

The results of the study, conducted by the Queen’s University of Belfast Public Health Center in the United Kingdom, indicate that environmental factors – especially environmental exposures – should be treated as risk enhancers in suicide prevention strategies.

Therefore, the authors recommend integrating environmental protection and urban planning as essential tools for suicide prevention.

The work recalls that, every year, more than 720,000 people die from suicide in the world, which led the World Health Organization to develop a Mental Health Action Plan to reduce this global public health problem, at least one third between 2013 and 2030.

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The effect of exposure to environmental factors on mental disorders such as depression or anxiety has been widely studiedbut the risk of suicide is less known.

To discover this, the researchers analyzed the existing data on environmental, acoustic, light and water pollution, and took into account socio-demographic factors such as gender and income, which could also influence the risk of death by suicide and suicidal behaviors.

After thoroughly searching the research databases and studies published in English between January 2010 and April 2024, the authors selected 45 studies (38 on environmental pollution, 3 on acoustics and one on light), of which 29 were submitted to a meta-analysis and 16 to a review.

The analysis showed that short-term exposure (less than six months) to suspended fine particles PM2.5 (13 studies) and PM10 (7 studies) and long-term exposure (over six months) to PM2.5 (6 studies) and NO2 (7 studies) are related in a statistically significant way to the risk of suicide death, suicide attempts and thoughts.

In addition, the review revealed the relationship with other air pollutants, such as sulphur dioxide (SO2), ozone (O3) and carbon monoxide (CO), and noise pollution. The limited number of studies prevented the evaluation of the effects of water and light pollution.

Finally, the analysis found clear associations between the risk of death by suicide or suicidal thoughts and sociodemographic factors.

The authors explain that the fact that pollution influences the risk of suicidal behaviour is due to the fact that air pollutants, including PM2.5, PM10, NO2, SO2 and O3, and water contaminated with arsenic, lead, lithium or nitrate, cause chronic inflammation and nervous damage, which alters brain function and influences mood and stress resistance.

Researchers also recall that there is evidence that noise pollution influences some mental health disorders, such as anxiety and depression, and that exposure to environmental noise, such as night or rail traffic, generates chronic stress and changes the biological clock.

Although researchers recognize several limitations in their findings, including the small number of studies available on each outcome, they conclude that the results “bring to light the crucial importance of recognizing environmental exposures as modifiable risk factors in suicide prevention efforts”.

“The integration of environmental health into mental health policies through intersectoral collaboration, pollution reduction strategies and public health interventions could play a vital role in reducing the risk of suicide and improving the general mental well-being of the population“, the authors write.