The impact of ambient air pollution on suicide mortality: a case-crossover study in Guangzhou, China

Are greenhouse gas emissions and cognitive skills related? Cross-country evidence

Are greenhouse gas emissions (GHG) and cognitive skills (CS) related? We attempt to answer this question by exploring this relationship, using cross-country data for 150 countries, for the period 1997-2012. After controlling for the level of economic development, quality of political regimes, population size and a number of other controls, we document that CS robustly predict GHG. In particular, when CS at a national level increase by one standard deviation, the average annual rate of air pollution changes by nearly 1.7% (slightly less than one half of a standard deviation). This significance holds for a number of robustness checks.

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

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.

Does air pollution trigger suicide? A case-crossover analysis of suicide deaths over the life span

In addition to underlying health disorders and socio-economic or community factors, air pollution may trigger suicide mortality. This study evaluates the association between short-term variation in air pollution and 10 years of suicide mortality in Belgium. In a bidirectional time-stratified case-crossover design, 20,533 suicide deaths registered between January 1st 2002 and December 31st 2011 were matched by temperature with control days from the same month and year. We used municipality-level air pollution [particulate matter (PM₁₀) and O₃ concentrations] data and meteorology data. We applied conditional logistic regression models adjusted for duration of sunshine and day of the week to obtain odds ratios (OR) and their 95% CI for an increase of 10 µg/m³ in pollutant concentrations over different lag periods (lag 0, 0-1, 0-2, 0-3, 0-4, 0-5, and 0-6 days). Effect modification by season and age was investigated by including interaction terms. We observed significant associations of PM₁₀ and O₃ with suicide during summer (OR ranging from 1.02 to 1.07, p-values <0.05). For O₃, significant associations were also observed during spring and autumn. Age significantly modified the associations with PM₁₀, with statistically significant associations observed only among 5-14 year old children (lag 0-6: OR = 1.45; 95% CI: 1.03-2.04) and ≥85 years old (e.g. lag 0-4: OR = 1.17; 95% CI: 1.06-1.29). Recent increases in outdoor air pollutants such as PM₁₀ or O₃ can trigger suicide, particularly during warm periods, even at concentrations below the European thresholds. Furthermore, PM₁₀ may have strong trigger effects among children and elderly population.

Reported association of air pollution and suicide rate could be confounded

A statistical association between ambient air pollution and suicide mortality has been recently reported in Environmental Health, which seems not to be scientifically supported by their data.In this article, very low (unrealistic) suicide rate is reported, which is subjected to selection bias. Their justification is also flawed as high exposure to ambient air pollution in rural areas is lower as compared to urban residents. Weekends, holidays, time of death … are also both air pollution and suicide rate related. Reported statistical association of air pollution and suicide in this study is heavily confound.Please see article under discussion: https://ehjournal.biomedcentral.com/articles/10.1186/s12940-016-0177-1 .