Air pollution, aeroallergens and suicidality: a review of the effects of air pollution and aeroallergens on suicidal behavior and an exploration of possible mechanisms

Abstract

Objective: Risk factors for suicide can be broadly categorized as sociodemographic, clinical and treatment. There is interest in environmental risk and protection factors for suicide. Emerging evidence suggests a link between environmental factors in the form of air pollution and aeroallergens in relation to suicidality. Methods: Herein, we conducted a systematic review of 15 articles which have met inclusion criteria on the aforementioned effects. Results: The majority of the reviewed articles reported an increased suicide risk alongside increased air pollutants or aeroallergens (i.e. pollen) increase; however, not all environmental factors were explored equally. In specific, studies that were delimited to evaluating particulate matter (PM) reported a consistent association with suicidality. We also provide a brief description of putative mechanisms (e.g. inflammation and neurotransmitter dysregulation) that may mediate the association between air pollution, aeroallergens and suicidality. Conclusion:Available evidence suggests that exposure to harmful air quality may be associated with suicidality. There are significant public health implications which are amplified in regions and countries with greater levels of air pollution and aeroallergens. In addition, those with atopic sensitivity may represent a specific subgroup that is at risk.

Suicide and Associations with Air Pollution and Ambient Temperature: A Systematic Review and Meta-Analysis

“…Suicide involves complicated interactions of various psychological, demographic, biological, and environmental factors [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. There is an emerging field of research for the complexity of the suicide phenomenon from the intersections between biological and nonbiological factors.…”

“…For example, neurological diseases can present with psychiatric diseases and intersect for the morphological and functional lesions in brain, which complicates biological models for suicide risk [ 10 , 11 ]. Potential environmental factors affecting suicide include air pollution and ambient temperature [ 8 ]. Although not fully identified, a biological rationale for impacts of air pollution and high temperature on suicide, including gene expression extending to the brain, neurotransmitters, and behavioral responses [ 12 ], is available from animal studies ( Figure 1 ).…”

“…Numerous population-based observational studies examined acute impacts of temperature and air pollution on suicide mortality, attempts, and ideation. To date, there are few systematic review studies on these associations [ 8 , 19 , 26 , 27 , 28 , 29 , 30 ]. For example, studies reported significant associations between suicide and short-term PM exposure with aerodynamic diameter ≤10 mm (PM 10 ) by combining evidence from four studies [ 29 ], and PM 10 and PM with aerodynamic diameter ≤2.5 mm (PM 2.5 ) by combining 10 studies [ 26 ].…”

“…This systematic review and meta-analysis aimed to summarize (1) the influence of air pollution and temperature on suicide; (2) differences in associations between air pollution or temperature and suicide by regional characteristics; and (3) limitations of identified studies (risk of bias) regarding study design and methodologies. Studies of air pollution and temperature vary in lag time (e.g., from daily to yearly scales) [ 8 ]. We focused on short-term exposure of days to weeks.…”

Dynamic UrbanEnvironmentalExposures onDepression andSuicide (NEEDS) in the Netherlands: a protocol for a cross-sectional smartphone tracking study and a longitudinal population register study

“…In terms of the salutogenic effects of blue space, the literature is limited 19. Air pollution seems to be positively correlated with mental disorders4 and suicidality 20. The health benefits of natural environments are also thought to be mediated through noise and air pollution 8 21 22.…”