Association between air pollution and suicide in South Korea: a nationwide study

Daily changes in ambient air pollution concentrations and temperature and suicide mortality in Canada: Findings from a national time-stratified case-crossover study

INTRODUCTION

Worldwide, approximately 1900 people die by suicide daily. Daily elevations in air pollution and temperature have previously been linked to a higher risk of death from suicide. To date, there have been relatively few studies of air pollution and suicide, particularly at a national level. National analyses play an important role in shaping health policy to mitigate against adverse health outcomes.

METHODS

We used a time-stratified case-crossover study design to investigate the influence of short-term (i.e., day to day) interquartile range (IQR) increases in air pollutants (nitrogen dioxide [NO₂], ozone [O₃], and fine particulate matter [PM_2.5]) and temperature on suicide mortality in Canada between 2002 and 2015. For air pollution models, odds ratios (ORs) derived from conditional logistic regression models were adjusted for average daily temperature, and holidays. For temperature models, ORs were adjusted for holidays. Stratified analyses were undertaken by suicide type (non-violent and violent), sex, age, and season.

RESULTS

Analyses are based on 50,800 suicide deaths. Overall, temperature effects were stronger than those for air pollution. A same day IQR increase in temperature (9.6 °C) was associated with a 10.1% increase (95% confidence interval (CI): 9.0%-11.2%) of death from suicide. For 3-day average increase of O₃ (IQR = 14.1 ppb), PM_2.5 (IQR = 5.6 μg/m³) and NO₂ (IQR = 9.7 ppb) the corresponding risks were 4.7% (95% CI: 3.9, 5.6), 3.4% (95% CI: 3.0, 3.8), and 2.0% (95% CI: 1.1, 2.8), respectively. All pollutants showed stronger associations with suicide during the warmer season (April-September). Stratified analyses revealed stronger associations for both temperature and air pollution in women.

CONCLUSIONS

Daily increases in air pollution and temperature were found to increase the risk of death from suicide. Females, particularly during warmer season, were most vulnerable to these exposures. Policy decisions related to air pollution and climate change should consider effects on mental health.

Can the perceived risk of particulate matter change people's desires and behavior intentions?

Particulate matter (PM) is a hazardous airborne pollutant that encompasses all airborne particles with diameters ranging from 0.001 to 100 μm. It is composed of total suspended particles (TSPs), consisting of two main particle sizes: PM10 and PM2.5. PM poses various threats to human health because of its rapid mobility and its ability to spread over a wide area. In particular, it has long-term negative effects on such organs as the lungs and heart. China and South Korea, located in Northeast Asia, are representative of the countries at risk of PM, and their populations live with an awareness that the harms of PM go beyond physical risks. Therefore, based on previous studies, this study classifies the perceived PM risks into physical, psychological, financial, functional, and time risks. It has tried to verify the effect of this risk perception on the behavior intention of Chinese and Koreans and examine the moderating effect according to the difference in nationality. The study's conceptual model was constructed by applying Ajzen's proven theory of planned action. Utilizing AMOS 22.0 and SPSS 22.0, an analysis was performed. Following this analysis, it was determined that there was a significant causal relationship between perceived PM risk and behavioral attitudes, subjective norms, and perceived behavioral control. Additionally, it was discovered that perceived PM risk significantly impacted desire and behavioral intention. These findings demonstrate that when persons are exposed to high concentrations of PM, they perceive a variety of risks that go beyond the merely physical, and they can form different attitudes depending on their nationality. This study greatly contributes to the theoretical and practical implications by presenting more diverse perspectives on PM risk.

Air pollution in association with mental and self-rated health and the mediating effect of physical activity

BACKGROUND

Recent studies showed that air pollution might play a role in the etiology of mental disorders. In this study we evaluated the association between air pollution and mental and self-rated health and the possible mediating effect of physical activity in this association.

METHODS

In 2008, 2013 and 2018 the Belgian Health Interview Survey (BHIS) enrolled 16,455 participants who completed following mental health dimensions: psychological distress, suboptimal vitality, suicidal ideation, and depressive and generalized anxiety disorder and self-rated health. Annual exposure to nitrogen dioxide (NO₂), particulate matter ≤ 2.5 µm (PM_2.5) and black carbon (BC) were estimated at the participants' residence by a high resolution spatiotemporal model. Multivariate logistic regressions were carried out taking into account a priori selected covariates.

RESULTS

Long-term exposure to PM_2.5, BC and NO₂ averaged 14.5, 1.4, and 21.8 µg/m³, respectively. An interquartile range (IQR) increment in PM_2.5 exposure was associated with higher odds of suboptimal vitality (OR = 1.27; 95% CI: 1.13, 1.42), poor self-rated health (OR = 1.20; 95% CI: 1.09, 1.32) and depressive disorder (OR = 1.19; 95% CI: 1.00, 1.41). Secondly, an association was found between BC exposure and higher odds of poor self-rated health and depressive and generalized anxiety disorder and between NO₂ exposure and higher odds of psychological distress, suboptimal vitality and poor self-rated health. No association was found between long-term ambient air pollution and suicidal ideation or severe psychological distress. The mediation analysis suggested that between 15.2% (PM_2.5-generalized anxiety disorder) and 40.1% (NO₂-poor self-rated health) of the association may be mediated by a difference in physical activity.

CONCLUSIONS

Long-term exposure to PM_2.5, BC or NO₂ was adversely associated with multiple mental health dimensions and self-rated health and part of the association was mediated by physical activity. Our results suggest that policies aiming to reduce air pollution levels could also reduce the burden of mental health disorders in Belgium.

Investigating relationship between particulate matter air concentrations and suicides using geographic information system

Exposure to particulate matter is an important risk factor for mental health disturbances and overall mortality. However, the knowledge on relationship between long-term particulate matter level and suicide rate is limited and requires in-depth study. Population and air pollution data were obtained from the Polish Central Statistics Office and Chief Inspectorate of Environmental Protection for the period 2014-2015. Aspatial multivariate and one factor regression analysis were performed and followed by spatial global regression analysis for district reference units in geographic information system (GIS). At the district level of aggregation, data showed spatial stationarity. The best-fitting spatial global model was based on number of disorders caused by the use of psychoactive substances, number of people treated in psychiatric hospitals, population density, unemployment rate and per capita income. Global spatial model with PM2.5 level parameter was an improvement over the one without it (adj. R2 = 0.87 compared to adj. R2 = 0.83). There is a positive relationship between particular matter concentrations and suicides in Poland. Application of Geographic Information Science analytical functions in medicine can be viewed as a new efficient methodological approach.

Relationship between chronic exposure to ambient air pollution and mental health in Korean adult cancer survivors and the general population

Background

Although a significant association between air pollution and mental health has been identified, few studies have addressed this relationship based on cancer diagnosis. This study investigated whether associations between long-term air pollution and mental health conditions differ based on whether the individual has been diagnosed with cancer.

Methods

Nationally representative data were used and a total of 38,101 adults were included in the analyses. We assessed mental health factors such as perceived stress, depressive symptoms, and suicidal ideation, and analyzed the associations between these factors and individuals’ annual average exposure to air pollutants, including particulate matter with an aerodynamic diameter ≤ 10 μm (PM₁₀), nitrogen dioxide, sulfur dioxide, and carbon monoxide.

Results

Compared with the general population, PM₁₀ exposure in cancer survivors predicted a higher risk of depressive symptoms (odds ratio [OR] =1.34; 95% confidence interval [CI] = 1.06–1.69) and suicidal ideation (OR = 1.29; 95% CI = 1.01–1.64). Notably, the statistically significant relationship between PM₁₀ exposure and suicidal ideation in cancer survivors disappeared after further adjustment for depressive symptoms (p = 0.3103). This pattern was also observed in the result of propensity score-matched analysis for comparison between cancer survivors and the general population.

Conclusions

This study provides the first evidence that cancer survivors with depressive symptoms may be more susceptible to suicidal ideation in the context of persistent PM₁₀ exposure.

Assessing Health Impacts of Winter Smog in Lahore for Exposed Occupational Groups

The goal of this research was to investigate the health effects of winter pollution on various occupations in Lahore and its neighboring peri-urban areas. A questionnaire survey, key informants, and focused group discussions were employed to collect data, which included demographic, socioeconomic, and health-related information. Descriptive statistics and the multivariate logistic regression model (MLRM) were used to examine the effects of pollution on exposed occupational groups who experienced symptoms such as coughing, shortness of breath, and eye discomfort. According to data from interviews, MLRM revealed that individuals working in various occupations with outdoor and indoor environments are equally affected by winter smog, but being middle-aged (odds ratio OR = 5.73), having a history of a respiratory ailment (OR = 4.06), and location (OR = 2.26) all play important roles in determining health. However, less educated people, elders, and people who already live in polluted areas are more likely to develop respiratory health symptoms. During the smog incident, it was determined that diverse health and socioeconomic factors exacerbate an individual’s negative health impact more than others.

Air Pollution: A Neglected Risk Factor for Dementia in Latin America and the Caribbean

The risk of dementia and Alzheimer's disease in Latin America and the Caribbean (LAC) rises with increasing age and polluted air. Currently, at least 172 million people breathe unhealthy levels of air pollution in LAC countries. Several cohort studies have indicated that air pollution increases the risk of developing dementia and neurodegenerative diseases, but the mechanisms underlying the association are still not clear. Air pollution causes and aggravates five established risk factors for dementia (obesity, hypertension, stroke, diabetes mellitus, and heart diseases) and is linked to three other risk factors (physical inactivity, cognitive inactivity, and depression). Some of these risk factors could be mediating the association between air pollution and dementia. Reducing the risks for dementia is crucial and urgently needed in LAC countries. There is room for improving air quality in many urban areas in the LAC region and other low- and middle-income countries (LMICs), a routealready explored by many urban areas in developing regions. Moreover, reducing air pollution has proved to improve health outcomes before. In this article, we propose that despite the ongoing and valid scientific discussion, if air pollution can or cannot directly affect the brain and cause or aggravate dementia, we are ready to consider air pollution as a potentially modifiable risk factor for dementia in LAC and possibly in other LMICs. We suggest that controlling and reducing current air pollution levels in LAC and other LMIC regions now could strongly contribute.

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

Given health threats of climate change, a comprehensive review of the impacts of ambient temperature and ar pollution on suicide is needed. We performed systematic literature review and meta-analysis of suicide risks associated with short-term exposure to ambient temperature and air pollution. Pubmed, Scopus, and Web of Science were searched for English-language publications using relevant keywords. Observational studies assessing risks of daily suicide and suicide attempts associated with temperature, particulate matter with aerodynamic diameter ≤10 μm (PM₁₀) and ≤2.5 mm (PM_2.5), ozone (O₃), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO) were included. Data extraction was independently performed in duplicate. Random-effect meta-analysis was applied to pool risk ratios (RRs) for increases in daily suicide per interquartile range (IQR) increase in exposure. Meta-regression analysis was applied to examine effect modification by income level based on gross national income (GNI) per capita, national suicide rates, and average level of exposure factors. In total 2274 articles were screened, with 18 studies meeting inclusion criteria for air pollution and 32 studies for temperature. RRs of suicide per 7.1 °C temperature was 1.09 (95% CI: 1.06, 1.13). RRs of suicide per IQR increase in PM_2.5, PM₁₀, and NO₂ were 1.02 (95% CI: 1.00, 1.05), 1.01 (95% CI: 1.00, 1.03), and 1.03 (95% CI: 1.00, 1.07). O₃, SO₂, and CO were not associated with suicide. RR of suicide was significantly higher in higher-income than lower-income countries (1.09, 95% CI: 1.07, 1.11 and 1.20, 95% CI: 1.14, 1.26 per 7.1 °C increased temperature, respectively). Suicide risks associated with air pollution did not significantly differ by income level, national suicide rates, or average exposure levels. Research gaps were found for interactions between air pollution and temperature on suicide risks.

A spatial epidemiology case study of mentally unhealthy days (MUDs): air pollution, community resilience, and sunlight perspectives

The main objective of this spatial epidemiologic research is to gain greater insights into the geographic dimension displayed by the different duration of mentally unhealthy days (MUDs) across U.S. counties. Mentally unhealthy days (MUDs) are studied in entire cross counties for year of 2014. Using Behavioural Risk Factor Surveillance System (BRFSS) data in 2014, we examine main factors of mental health hazard including health behaviour, clinical care, socioeconomic and physical environment, demographic, community resilience, and extreme climatic conditions. In this study, we take complex design factors such as clustering, stratification and sample weight in the BRFSS data into account by using Complex Samples General Linear Model (CSGLM). Then, spatial regression models, spatial lag and error models, are applied to examine spatial dependencies and heteroscedasticity. Results of the geographic analyses indicate that counties with lower air pollution (PM2.5), higher community resilience (social, economic, infrastructure, and institutional resilience), and higher sunlight exposure had significantly lower average number of MUDs reported in the past 30 days. These findings suggest that policy makers should take air pollution, community resilience, and sunlight exposure into account when designing environmental and health policies and allocating resources to more effectively manage mental health problems.

The association between ozone and fine particles and mental health-related emergency department visits in California, 2005-2013

Recent studies suggest that air pollutant exposure may increase the incidence of mental health conditions, however research is limited. We examined the association between ozone (O3) and fine particles (PM2.5) and emergency department (ED) visits related to mental health outcomes, including psychosis, neurosis, neurotic/stress, substance use, mood/affective, depression, bipolar, schizotypal/delusional, schizophrenia, self-harm/suicide, and homicide/inflicted injury, from 2005 through 2013 in California. Air monitoring data were provided by the U.S. EPA's Air Quality System Data Mart and ED data were provided by the California Office of Statewide Health Planning and Development. We used the time-series method with a quasi-Poisson regression, controlling for apparent temperature, day of the week, holidays, and seasonal/long-term trends. Per 10 parts per billion increase, we observed significant cumulative 7-day associations between O3 and all mental health [0.64%, 95% confidence interval (CI): 0.21, 1.07], depression [1.87%, 95% CI: 0.62, 3.15], self-harm/suicide [1.43%, 95% CI: 0.35, 2.51], and bipolar [2.83%, 95% CI: 1.53, 4.15]. We observed 30-day lag associations between O3 and neurotic disorder [1.22%, 95% CI: 0.48, 1.97] and homicide/inflicted injury [2.01%, 95% CI: 1.00, 3.02]. Same-day mean PM2.5 was associated with a 0.42% [95% CI: 0.14, 0.70] increase in all mental health, 1.15% [95% CI: 0.62, 1.69] increase in homicide/inflicted injury, and a 0.57% [95% CI: 0.22, 0.92] increase in neurotic disorders per 10 μg/m3 increase. Other outcomes not listed here were not statistically significant for O3 or PM2.5. Risk varied by age group and was generally greater for females, Asians, and Hispanics. We also observed seasonal variation for outcomes including but not limited to depression, bipolar, schizophrenia, self-harm/suicide, and homicide/inflicted injury. Ambient O3 or PM2.5 may increase the risk of mental health illness, though underlying biological mechanisms remain poorly understood. Findings warrant further investigation to better understand the impacts of air pollutant exposure among vulnerable groups.

Meteorological Variables and Suicidal Behavior: Air Pollution and Apparent Temperature Are Associated With High-Lethality Suicide Attempts and Male Gender

This study analyzed the impact of meteorological variables and high-lethality suicide attempts (HLSA) to assess a potential time shift of HLSA affected by climate evolution to predict the suicide attempt cases over different periods of the year. After attempting suicide, 225 subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the psychiatric unit from March 2016 to July 2018. Socio-demographic and clinical characteristics as well as the meteorological variables were collected. The Mann-Kendall test as well as redundancy and cross-correlation analyses were performed to analyze the trends, statistically correlations, and correspondence of the trends, respectively between suicidal behaviors and climatic factors. Sixty-seven (29.8%) committed a HLSA. Our findings indicate a significant association between HLSA and male gender and apparent temperature with a strong correlation of 75% with a phase shift of -1 month. Solar radiation and air pollution (PM_2.5) have a positive correlation of 65 and 32%, respectively, with a zero-time lag. Limitations include that the data are limited to a single hospital; psychological factors, or other clinical variables that could be ruled out as a trigger have not been considered. Meteorological variables may not mirror the temperature that the patient is exposed to due to the air conditioning systems. Exploring those environmental factors associated with HLSA in a more detailed manner could lead to early intervention and prevention strategies for such distressing admissions.

Air Pollution, Stress, and Allostatic Load: Linking Systemic and Central Nervous System Impacts

 Air pollution is a risk factor for cardiovascular and respiratory morbidity and mortality. A growing literature also links exposure to diverse air pollutants (e.g., nanoparticles, particulate matter, ozone, traffic-related air pollution) with brain health, including increased incidence of neurological and psychiatric disorders such as cognitive decline, dementia (including Alzheimer’s disease), anxiety, depression, and suicide. A critical gap in our understanding of adverse impacts of pollutants on the central nervous system (CNS) is the early initiating events triggered by pollutant inhalation that contribute to disease progression. Recent experimental evidence has shown that particulate matter and ozone, two common pollutants with differing characteristics and reactivity, can activate the hypothalamic-pituitary-adrenal (HPA) axis and release glucocorticoid stress hormones (cortisol in humans, corticosterone in rodents) as part of a neuroendocrine stress response. The brain is highly sensitive to stress: stress hormones affect cognition and mental health, and chronic stress can produce profound biochemical and structural changes in the brain. Chronic activation and/or dysfunction of the HPA axis also increases the burden on physiological stress response systems, conceptualized as allostatic load, and is a common pathway implicated in many diseases. The present paper provides an overview of how systemic stress-dependent biological responses common to particulate matter and ozone may provide insight into early CNS effects of pollutants, including links with oxidative, inflammatory, and metabolic processes. Evidence of pollutant effect modification by non-chemical stressors (e.g., socioeconomic position, psychosocial, noise), age (prenatal to elderly), and sex will also be reviewed in the context of susceptibility across the lifespan.

Long-term effects of ambient air pollutants on suicidal ideation in China: The Henan Rural Cohort Study

BACKGROUND

The association between ambient air pollutants exposure and suicidal ideation (SI) has rarely been explored, especially in Chinese population. Therefore, we aimed to investigate the long-term effects of ambient air pollutants on SI among a Chinese rural population.

METHOD

We recruited 29997 participants from the Henan Rural Cohort study in 2016-2017. SI was evaluated by using the ninth item of the Patient Health Questionnaire-9 (PHQ-9) in the baseline survey. We adopted a satellite-based spatiotemporal model to estimate participants' exposure to particulate matters (PMs) (PM with an aerodynamic diameter ≤1 μm (PM₁), ≤2.5 μm (PM_2.5) or ≤10 μm (PM₁₀), respectively) and nitrogen dioxide (NO₂), and then calculated the 3-year average concentrations of the four pollutants. We used logistic regression models to explore the association between long-term exposure to ambient air pollutants and SI. In addition, we conducted several stratified analyses to examine effect modification of selected factors.

RESULTS

The odds ratios (95% confidence intervals [CI]) of SI in response to each 1 μg/m³ increase in PM₁, PM_2.5, PM₁₀ and NO₂ concentrations were 1.08 (1.01, 1.15), 1.10 (1.02, 1.19), 1.05 (1.01, 1.09) and 1.12 (1.04, 1.21), respectively. Individuals exposed to PM₁, PM_2.5, PM₁₀ or NO₂ concentrations in the fourth quartile had a 1.36-fold (95%CI: 1.08, 1.72), 1.69-fold (95%CI: 1.05, 2.72), 1.49-fold (95%CI: 1.09, 2.05) or 1.71-fold (95%CI: 1.15, 2.85) risks of SI, compared to the ones with corresponding air pollutants in the first quartile. Besides, the risks of SI increased with the quartiles of air pollutants (PM₁: P_trend = 0.002, PM_2.5: P_trend = 0.003, PM₁₀: P_trend = 0.010, NO₂: P_trend = 0.010). Stratified analyses suggested that males, highly educated participants, ever-drinkers and people aged range 36-64 years were more vulnerable to the adverse effects of air pollutants.

CONCLUSIONS

This study provided evidence for the long-term effects of ambient PMs and NO₂ on SI in rural Chinese adults, particularly for males, highly educated participants, ever-drinkers and people aged range 36-64 years.

Factors Associated with Regional Years of Life Lost (YLLs) due to Suicide in South Korea

South Korea’s suicide rate has remained among the highest in the world for some years, and there is also a gap in suicide rates among regions within the country. This study investigates the differences in years of life lost (YLLs) due to suicide in 250 districts and the factors associated with regional YLLs in South Korea in 2016. The relationships between YLLs due to suicide by region and factors such as population characteristics, health behaviors, socioeconomic factors, and mental health resources in the community were examined through multiple linear regression analysis. The gap between districts with the highest and lowest YLL due to suicide per 100,000 people was more than a 7-times difference. Factors related to YLLs due to suicide by region were physical activity rates and community mental healthcare centers, and there were differences in these factors according to gender. In conclusion, to prevent suicide at the community level, it is necessary to consider gender in establishing intervention strategies. The community needs to play an active role in promoting mental health and reducing suicide among local residents and to continue to invest in the support and management of those at high risk of suicide.

Climate Change and Risk of Completed Suicide

Climate change is increasingly recognized as having multiple adverse mental health effects, many of which are just beginning to be understood. The elevated rates of suicides observed in some communities affected by climate change and rising rates of suicide in the United States as climate change intensifies have suggested the two may be associated. We searched PubMed and PsycInfo using the terms climate change and suicide, and provide here a review of the current literature on climate change and suicide that explores possible associations and methodological issues and challenges in this research.

Air Pollution and Emergency Department Visits for Mental Disorders among Youth

Although exposure to ambient air pollution has been linked to mental health problems, little is known about its potential effects on youth. This study investigates the association between short-term exposure to air pollutants and emergency department (ED) visits for mental health disorders. The National Ambulatory Care Reporting System database was used to retrieve ED visits for young individuals aged 8–24 years in Toronto, Canada. Daily average concentrations of nitrogen dioxide (NO₂), fine particulate matter (PM_2.5), and daily maximum 8 h ozone (O₃) were calculated using measurement data from seven fixed stations. A case-crossover (CC) design was implemented to estimate the associations between ED visits and air pollution concentrations. Mental health ED visits were identified using International Classification of Diseases 10th Revision (ICD-10) codes, with seven categories considered. Models incorporating air pollutants and ambient temperature (with lags of 0–5 days) using a time-stratified CC technique were applied. Multivariable regression was performed by sex, three age groups, and seven types of mental health disorders to calculate relative risk (RR). The RRs were reported for one interquartile range (IQR) change in the air pollutant concentrations. Between April 2004 and December 2015 (4292 days), there were 83,985 ED visits for mental-health related problems in the target population. Several exposures to air pollutants were shown to have associations with ED visits for mental health including same day exposure to fine particulate matter (IQR = 6.03 μg/m³, RR = 1.01 (95% confidence interval: 1.00–1.02), RR = 1.02 (1.00–1.03)) for all and female-only patients, respectively. One-day lagged exposure was also associated with ED visits for PM_2.5 (RR = 1.02 (1.01–1.03)), for nitrogen dioxide (IQR = 9.1 ppb, RR = 1.02 (1.00–1.04)), and ozone (IQR = 16.0 ppb, RR = 1.06 (1.01–1.10)) for males. In this study, urban air pollution concentration—mainly fine particulate matter and nitrogen dioxide—is associated with an increased risk for ED visits for adolescents and young adults with diagnosed mental health disorders.

Suicide behavior and meteorological characteristics in hot and arid climate

BACKGROUND

Suicidal behavior is determined by the consequence of an interaction between biological, psychological and sociological factors, as well as between individual and environmental effects. Fluctuations in meteorological factors can modify human behavior and affect suicidal rates. We hypothesize that high temperatures can be associated with an increase rate of suicidal attempts.

METHODS

We included all the patients admitted to Soroka University Medical Center (SUMC) due to suicide attempts between the years 2002-2017 and were residents of Southern Israel. We computed two sets of regression models: first, a time stratified case-crossover design to control for seasonality and individual differences. Results are presented as odds ratio (OR) with confidence interval (CI); and then, time-series analyses to calculate the incidence rate ratio (IRR) and the cumulative effect of temperature on the daily incidences of emergency department (ED) admissions after suicide attempts. We stratified the analyses by demographic variables to identify significant individual differences.

RESULTS

We identified 3100 attempts, by 2338 patients who lived in Be'er Sheva between 16 and 90 years of age; 421 patients made 2+ attempts. Suicide attempts were associated with a 5 °C increase during the summer season (OR 1.59, 95% CI 1.22-2.08) and a 5 °C increase in all seasons was associated with those who have made multiple attempts (OR 1.18, 95% CI 1.0005-1.38). The cumulative effect of 5 °C increment is associated with more suicide attempts over 2 days (IRR 1.10, 95% CI 0.98; 1.24) and 5 days (IRR 1.04, 95% CI 1.00; 1.08). The associations were greater for patients with psychiatric diagnosis and patients with multiple attempts. In a stratified analysis by individual characteristics we didn't find significant association.

CONCLUSION

High temperatures and low amount of precipitations are evidently of great impact on people's susceptibility to suicidal behavior, especially for individuals who have had a prior suicide attempt. Our findings indicate the need for public health attention in the summer when temperature increases precipitously over days, especially for those who have made a prior suicide attempt.

Short-term effects of traffic noise on suicides and emergency hospital admissions due to anxiety and depression in Madrid (Spain)

Studies show a relationship between some mental illnesses and suicides and different environmental variables such as air pollution, characterized by stress at the neuropsychological level. Despite the fact that traffic noise is also a powerful neurological stressor, studies that relate traffic noise to these mental disorders are practically non-existent. The objective is to analyze the short-term impact that chemical air pollution, traffic noise and thermal extremes have on emergency hospital admissions due to anxiety, dementia and suicides in the city of Madrid. This ecological, longitudinal study uses generalized linear models with Poisson link to analyze the short-term impact of the average daily concentrations of chemical pollutants (NO₂, PM₁₀, PM_2.5, O₃), noise pollution indicators (Leq_day, Leq_night and Leq_24h) and temperatures during heat waves (T_heat) and cold waves (T_cold) on daily admissions to emergency services in the city of Madrid from 2010 to 2013 due to anxiety (ICD-10: F32), depression (ICD-10: F40-F42) and suicide (ICD-10: X60-X84). The results show no association between any of the chemical pollutants considered and the dependent variables studied. On the contrary, the values of Leq_day are associated with the three variables analyzed in lag 0 for the cases of anxiety and depression and in lag 1 for suicides, with RR: 1.20 (IC95% 1.14 1.26), RR: 1.11 (IC95% 1.06 1.16) and RR: 1.17 (IC95% 1.05 1.30), respectively, for increases of 1 dB(A) in the values of Leq_day. An association was also found between T_cold and admissions for anxiety in lag 9 with RR: 1.62 (IC95% 1.18 2.22) for increases of 1 °C in the values of T_cold. Traffic noise can be considered an important risk factor related to the illnesses and anxiety and depression and for suicides in the city of Madrid, although new studies are needed to support the findings shown here.

The association between PM2.5 exposure and suicidal ideation: a prefectural panel study

Background

Suicidal ideation is subject to serious underestimation among existing public health studies. While numerous factors have been recognized in affecting suicidal thoughts and behaviors (STB), the associated environmental risks have been poorly understood. Foremost among the various environment risks were air pollution, in particular, the PM2.5. The present study attempted to examine the relationship between PM_2.5 level and local weekly index of suicidal ideation (ISI).

Methods

Using Internet search query volumes in Baidu (2017), the largest internet search engine in China, we constructed a prefectural panel data (278 prefectures, 52 weeks) and employed dynamic panel GMM system estimation to analyze the relationship between weekly concentration of PM2.5 (Mean = 87 μg·m^− 3) and the index of suicidal ideation (Mean = 49.9).

Results

The results indicate that in the spring and winter, a 10 μg·m^− 3 increase in the prior week’s PM_2.5 in a Chinese city is significantly associated with 0.020 increase in ISI in spring and a 0.007 increase in ISI in winter, after taking account other co-pollutants and meteorological conditions.

Conclusion

We innovatively proposed the measure of suicidal ideation and provided suggestive evidence of a positive association between suicidal ideation and PM_2.5 level.

The Impact of Ambient Fine Particulate Matter on Consumer Expenditures

Airborne particulate matter suspended from industrial facilities, power plants, and automobiles is detrimental to health. Growing concerns about the increasing level of airborne particulate matter have led many industrialized nations to advocate for the transformation of the energy market and investment in sustainable energy products. At the other end, consumers have made individual adjustments and attempted to reduce the exposure to the particulate matter. In this paper, we focus on the effect of ambient air pollution on consumer expenditures based on scanner panel data on consumers’ debit and credit card transactions. A series of empirical analyses found robust evidence that the increased level of particulate matter led to considerable disruption in total consumer expenditures with significant heterogeneity across categories. Our findings suggest that consumers alter their spending behaviors in an attempt to reduce the risk of exposures to particulate matter. Such an estimated effect of air pollution is qualitatively different from those of other macroeconomic factors and provides important guidance for policy interventions and practical decisions aimed at sustaining economic growth.

Air Pollution (Particulate Matter) Exposure and Associations with Depression, Anxiety, Bipolar, Psychosis and Suicide Risk: A Systematic Review and Meta-Analysis

BACKGROUND

Particulate air pollution's physical health effects are well known, but associations between particulate matter (PM) exposure and mental illness have not yet been established. However, there is increasing interest in emerging evidence supporting a possible etiological link.

OBJECTIVES

This systematic review aims to provide a comprehensive overview and synthesis of the epidemiological literature to date by investigating quantitative associations between PM and multiple adverse mental health outcomes (depression, anxiety, bipolar disorder, psychosis, or suicide).

METHODS

We undertook a systematic review and meta-analysis. We searched Medline, PsycINFO, and EMBASE from January 1974 to September 2017 for English-language human observational studies reporting quantitative associations between exposure to PM < 1.0 μ m in aerodynamic diameter (ultrafine particles) and PM < 2.5 and < 10 μ m in aerodynamic diameter (PM 2.5 and PM 10 , respectively) and the above psychiatric outcomes. We extracted data, appraised study quality using a published quality assessment tool, summarized methodological approaches, and conducted meta-analyses where appropriate.

RESULTS

Of 1,826 citations identified, 22 met our overall inclusion criteria, and we included 9 in our primary meta-analyses. In our meta-analysis of associations between long-term (> 6   months ) PM 2.5 exposure and depression (n = 5 studies), the pooled odds ratio was 1.102 per 10 - μ g / m 3 PM 2.5 increase (95% CI: 1.023, 1.189; I 2 = 0.00 % ). Two of the included studies investigating associations between long-term PM 2.5 exposure and anxiety also reported statistically significant positive associations, and we found a statistically significant association between short-term PM 10 exposure and suicide in meta-analysis at a 0-2 d cumulative exposure lag.

DISCUSSION

Our findings support the hypothesis of an association between long-term PM 2.5 exposure and depression, as well as supporting hypotheses of possible associations between long-term PM 2.5 exposure and anxiety and between short-term PM 10 exposure and suicide. The limited literature and methodological challenges in this field, including heterogeneous outcome definitions, exposure assessment, and residual confounding, suggest further high-quality studies are warranted to investigate potentially causal associations between air pollution and poor mental health. https://doi.org/10.1289/EHP4595.

Association between dust storm occurrence and risk of suicide: Case-crossover analysis of the Korean national death database

BACKGROUND

Asian dust storms (ADSs) have been associated with adverse health outcomes, including respiratory and cardiovascular diseases. Considering the increasing global desertification driven by climate change, it is necessary to assess dust storm-related adverse health effects for establishing appropriate public health interventions. Recent studies have found that ambient air pollution has negative effects on mental health including cognitive disorders, depression, and suicide. However, these studies mostly focused on traditional anthropogenic pollutants from traffic exhaust or fossil fuel power plants; the association between dust storms and suicidal death is yet to be determined.

OBJECTIVE

To assess the association between ADSs and suicide risk in Seoul, South Korea from 2002 to 2015.

METHODS

To determine whether increased risk of suicide is associated with occurrence of ADSs, we performed a time-stratified case-crossover study that linked the national death statistics database with ADS occurrence data from the Korea Meteorology Administration. Exposure to ADSs was compared between the day of suicide and control days, matched to the day of the week, month, and year. We further examined whether the effect of ADSs on suicide risk differed according to ADS duration and intensity.

RESULTS

Over the 14-year period, 30,704 people died by suicide and 133 ADSs were reported. Of these, 55 ADSs lasted over 2 days (long-duration ADSs), and 67 ADSs had higher levels of particulate matter < 10 μm in diameter (PM₁₀) that exceeded the 50th percentile value over the total 133 ADS days (high-intensity ADSs). Exposure to ADS was associated with a 13.1% (95% confidence interval [CI], 4.5-22.4; P = .002) increase in suicide risk on the day of ADS occurrence. Long-duration and high-intensity ADSs were associated with a 19.8% (95% CI, 6.5-34.7; P = .003) and 17.0% (95% CI, 5.2-30.0; P = .004) increase in suicide risk, respectively. These associations remained robust after adjusting for local air pollution levels and meteorological factors. However, this association was not replicated in the unconstrained distributed lag model which revealed inferior goodness-of-fit to our data.

CONCLUSIONS

Exposure to ADSs was associated with an increased risk of suicide, especially on the same day. This study provides novel evidence of a relationship between ADSs and suicide. These findings could help in establishing public health interventions for suicide prevention as well as in establishing dust storm warning systems. Future studies are warranted to confirm if our findings are replicable and to elucidate the underlying mechanisms.

Design and Methods of the Korean National Investigations of 70,000 Suicide Victims Through Police Records (The KNIGHTS Study)

OBJECTIVE

The suicide rate in South Korea was the second highest among the Organization for Economic Cooperation and Development countries in 2017. The purpose of this study is to understand the characteristics of people who died by suicide in Korea from 2013-2017 and to better prevent suicide.

METHODS

This study was performed by the Korea Psychological Autopsy Center (KPAC), an affiliate of the Korea Ministry of Health and Welfare. According to the Korea National Statistical Office, the number of suicide victims nationwide was estimated to reach about 70,000 from 2013 to 2017. Comprehensive suicide records from all 254 police stations in South Korea were evaluated by 32 investigators who completed a 14-day didactic training program. Then, we evaluated the characteristics of suicide victims in association with disease data from the National Health Insurance Database (NHID), which is anonymously linked to personal information of suicide victims.

RESULTS

Thirty-one of 254 police stations in the Seoul metropolitan area were analyzed by August 10, 2018. Findings showed that the characteristics of suicide victims differed according to the nature of the region.

CONCLUSION

Our results suggest that different strategies and methods are needed to prevent suicide by regional groups.

Does ambient ozone air pollution trigger suicide attempts? A case cross-over analysis in Taipei

Epidemiologic studies indicated that exposure to ambient air pollutants was associated with increased mortality rates attributed to suicide. The objective of this study was to investigate the potential relationship between ambient ozone (O₃) levels and daily number of hospital admissions for suicide attempts in Taipei for the period 2008-2012 using a time-stratified case-crossover analysis. In the single-pollutant model (without adjustment for other pollutants), the risk of committing a suicide attempt increased by 9% on warm days and 27% on cool days for each interquartile range (IQR) rise in O₃ levels, respectively. The concentration of O₃ was thus significantly associated with daily number of suicide attempts both on warm and cool days. In the two-pollutant models, O₃ levels remained significant after the inclusion of other air pollutants (particulate matter (PM₁₀), PM_2.5, sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO)) on cool days. However, on warm days, no significant correlation was found between O₃ levels and reported daily number of suicide attempts. The relationship between O₃ and suicide attempts appeared to be dependent upon temperature; however, the basis for these observations requires further investigation.

Associations between ambient high temperatures and suicide mortality: a multi-city time-series study in China

Suicide prevention has become a public health issue of great concern. Previous studies proved that ambient temperature had an impact on suicide death, but few studies focus on regional studies in large cities. We aimed to estimate the association between ambient temperature and suicide in 31 capital cities in China during 2008~2013. Distributed lag non-linear model was used to explore the relationship between ambient temperature and suicide, adjusting for long-term trend, seasonality, and humidity confounders. Multivariate meta-analysis was used to pool the city-specific estimates to explore the overall relative risk in China. High temperature had a significant impact on suicide death. The country-level relative risk of high temperature on suicide was 1.37 (95% CI, 0.96~2.57), and the RR was higher in male and age < 65-year-old group than that in female and age ≥ 65-year-old group. There has no consistent pattern of associations in city-level with sex and age. The high temperature has a greater impact on suicide in south region compared with north region. We found the positive association between ambient temperature and suicide in China.

Short-term PM2.5 exposure and emergency hospital admissions for mental disease

Epidemiologic studies regarding the relationship between short-term exposure to particulate matter with a median aerodynamic diameter < 2.5 µm (PM_2.5) and mental disease are limited. This study examined the effects of short-term exposure to PM_2.5 on emergency admissions to the hospital for mental disease in Seoul, Korea. Data regarding 80,634 emergency admissions for mental diseases were collected from a nationally centralized healthcare claims database in Seoul during 2003-2013. Generalized linear models with climate variables were used to examine associations between short-term PM_2.5 exposure and mental disease admissions. To comprehensively assess PM_2.5 effects, we used single- and two-pollutant models, which considered other pollutants in combination with PM_2.5. The relative risk (RR) of emergency admissions for mental disease was 1.008 (95% confidence interval, 1.001-1.015) for each 10 μg/m³ increase in 2-day average PM_2.5 concentration. This effect persisted or became slightly stronger in the two-pollutant models that included carbon monoxide, nitrogen dioxide, ozone, or sulfur dioxide (RR, 1.01-1.021), but association appeared to be limited to individuals < 65 years of age. Significant association was estimated only during the warm season (RR, 1.021-1.023) in the two-pollutant models. The exposure-response curve was steeper at lower concentrations, suggesting that the risk of mental disease at lower concentrations of pm2.5 (0-30 µg/m³). PM_2.5 was associated with increased admissions even when it was below the World Health Organization's Air Quality Guidelines (25 μg/m³), but the association was not statistically significant. Thus, based on the data from a large database, exposure to PM_2.5 was associated with increases in emergency admissions for mental diseases, and this association was significant during the warm season. PM_2.5 may even affect mental disease at levels below the current air quality guidelines. These results provide substantial insight regarding the effects of air pollutants and have important implications for policy makers.

Relationship between ozone air pollution and daily suicide mortality: a time-stratified case-crossover study in Taipei

Several studies suggested short-term exposure to air pollution might be associated with suicide mortality, although results have been inconsistent and vary depending upon the type of air contaminants. While seasonal variation associated with suicide was reported to occur and that in the spring and early summer there are peaks in ozone (O₃) distribution, the relationship between these two parameters is not known. The aim of this study was to examine the potential association between O₃ levels and daily mortality rate related to suicide in Taipei for the period 2004-2008 using a time-stratified case-crossover analysis. In our single pollutant model without adjustment for other pollutants, the risk of suicide increased by 11% on warm days and 15% on cool days for each interquartile range (IQR) rise in O₃ concentration, respectively. The relationship was positive but did not reach significance. In our two-pollutant models, O₃ remained non-significant on warm days after inclusion of one of any other ambient air contaminants into the model. However, on cool days, a significant association was found between O₃ levels and enhanced risk of mortality due to suicide after nitrogen dioxide (NO₂) or carbon monoxide (CO) were included. The overall positive but not significant findings of elevated risk of mortality frequently attributed to suicide on days with higher O₃ levels suggest that outdoor exposures to this gaseous contaminant may contribute to increases in daily mortality rate related to suicide.

Ambient air pollution and completed suicide in 26 South Korean cities: Effect modification by demographic and socioeconomic factors

Air pollution has been recently associated with suicide mortality. However, limited studies have examined possible effect modification of the association by various demographic and socioeconomic factors, despite their crucial roles on suicide risk. In 73,445 completed suicide cases from 26 South Korean cities from 2002 to 2013, we studied the association of suicide risk with exposure to particles <10 μm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ozone (O₃), and carbon monoxide (CO), using a city-specific conditional logistic regression analysis with a case-crossover design. Random effects meta-analysis was used to pool the results. We considered a delayed effect of air pollution by constructing lags of up to 7 days. We explored effect modification by demographic and socioeconomic factors (sex, age, education level, job, and marital status) as well as place of death, method of suicide, and season, through stratified subgroup analyses. Among five pollutants, NO₂ showed the strongest association at immediate lags (percent change in odds ratio; PM₁₀: 1.2% [95% CI, 0.2%, 2.3%]; NO₂: 4.3% [95% CI, 1.9%, 6.7%]; SO₂: 2.2% [95% CI, 0.7%, 3.8%]; O₃: 1.5% [95% CI, -0.3%, 3.2%]; and CO: 2.4% [95% CI, 0.9%, 3.8%] per interquartile range increase at lag0). In subgroup analyses by socioeconomic factors, stronger associations were observed in the male sex, the elderly, those with lower education status, white-collar workers, and the married; the largest association was an 11.0% increase (95% CI, 4.1%, 18.4%) by NO₂ among white-collar workers. We add evidence of effect modification of the association between air pollution exposure and suicide risk by various demographic and socioeconomic factors. These findings can serve as the basis for suicide prevention strategies by providing information regarding susceptible subgroups.

Is there a link between air pollution and mental disorders?

Several studies have demonstrated the association between air pollution and different medical conditions including respiratory and cardiovascular diseases. Air pollutants might have a role also in the etiology of mental disorders in the light of their toxicity on central nervous system. Purpose of the present manuscript was to review and summarize available data about an association between psychiatric disorders and air pollution. A research in the main database sources has been conducted to identify relevant papers about the topic. Different air pollutants and in particular PM and nitric oxides have been associated with poor mental health; long exposition to PM_2.5 has been associated with an increased risk of new onset of depressive symptoms (Cohen's effect size d: 0.05-0.81), while increased concentration of nitric dioxide in summer with worsening of existing depressive conditions (Cohen's effect size d: 0.05-1.77). However, the interpretation of these finding should take into account the retrospective design of most of studies, different periods of observations, confounding factors such as advanced age or medical comorbidity. Further studies with rigorous methodology are needed to confirm the results of available literature about this topic.

Ambient ozone exposure and mental health: A systematic review of epidemiological studies

BACKGROUND

An increasing number of studies have suggested adverse effects of air pollution on mental health. Given the potentially negative impacts of ozone exposure on the immune and nervous system driven from animal experiments, ozone might also affect mental health. However, no systematic synthesis of the relevant literature has been conducted yet. This paper reviews the studies that assessed the link between ozone exposure and mental health thus far.

METHODS

We followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA). PubMed, Web of Science, and EMBASE were systematically searched for epidemiological studies on ambient ozone exposure and mental or behavioral disorders according to the International Classification of Disease. The period was from January 1st, 1960 to December 14st, 2017. We evaluated the risk of bias by the Office of Health Assessment and Translation (OHAT) Approach and Navigation Guide for each included study.

RESULTS

The keyword search yielded 567 results. 31 papers met the selection criteria and were included in the review. We found only inconclusive evidence that ozone affects autism spectrum disorders, impairment of cognitive functions and dementia, depression, and suicide. The large heterogeneity of study designs, outcome definitions and study quality in general prevented us from conducting meta-analyses.

CONCLUSIONS

Current evidence for an association between ambient ozone exposure and mental health outcomes is inconclusive and further high quality studies are needed to assess any potential links given the strong biologic plausibility.

Air pollution influences the incidence of otitis media in children: A national population-based study

Background

Otitis media (OM) is a major reason for children’s visits to physicians and a major cause of their being treated with antibiotics. It not only causes economic burdens but also influences hearing, speech, and education. To our knowledge, no nationwide population-based study has assessed the association between air pollution and OM. Therefore, this study evaluated the association between air pollution levels and the incidence of OM.

Methods

We identified cases of OM that occurred in South Korea between January 2011 and December 2012 from the Korea National Health Insurance Service-National Sample Cohort database, and evaluated its relationship with five air pollutants: particulate matter (PM₁₀, particulates ≤10 μm in diameter), nitrogen dioxide (NO₂), ozone (O₃), sulfur dioxide, and carbon monoxide. Associations between the weekly incidence of OM and the five air pollutants were analyzed using generalized estimating equations. Conditional logistic regression analysis was used to obtain odds ratios (ORs) and their 99.9% Bonferroni-corrected confidence intervals after adjusting for gender, age, season, and region.

Results

We based our analysis on 160,875 hospital visits for OM by children aged <15 years. Correlations with higher concentrations of the five pollutants showed higher ORs than did the reference values at most time lags. PM₁₀ had the largest influence on the OM incidence at a time lag of 0 weeks, whereas NO₂ and O₃ had the largest impacts on OM incidence at time lags of 1 and 4 weeks, respectively.

Conclusion

These findings support the notion that the incidence of OM is associated with ambient air pollution.

Association between dry eye symptoms and suicidal ideation in a Korean adult population

Purpose

This study assessed the association of dry eyes with depression and suicidal ideation in a Korean adult population.

Methods

Data from 16408 participants (6972 men and 9436 women) aged ≥ 19 years included in the fifth Korea National Health and Nutrition Examination Survey, conducted from 2010–2012, were analyzed. For dry eyes, surveys of previous diagnosis of dry eye disease (DED) by an ophthalmologist and experience of subjective dry eye symptoms were separately used. Diagnosis of depression and suicidal ideation were obtained via responses to an interviewer-assisted questionnaire, and questions were asked in a closed-ended response format. Logistic regression was used to examine the associations between dry eyes, depression, and suicidal ideation.

Results

DED diagnosis exhibited an odds ratio (OR) of 1.32 (95% confidence interval [CI] 1.11–1.57) for depression and 1.24 (95% CI 1.05–1.48) for suicidal ideation compared to those without DED, after adjusting for sex, age, education, occupation, household income, body mass index, smoking behavior, alcohol consumption, physical activity, hypertension, diabetes, dyslipidemia, thyroid diseases, major cardiovascular disease, and cancer. Similarly, the adjusted OR (95% CI) of dry eye symptoms was 1.50 (95% CI 1.30–1.73) for depression and 1.47 (95% CI 1.27–1.70) for suicidal ideation.

Conclusion

Our findings suggest that dry eyes (either DED diagnosis or dry eye symptoms) may be associated with the prevalence of depression and suicidal ideation in the Korean adult population.

Association between air pollution and suicide: a time series analysis in four Colombian cities

BACKGROUND

Recent epidemiological studies have suggested that air pollution could be associated with suicide. However, other studies have criticized these results for being analytically weak and not taking into account potential confounding factors. As such, further studies examining the relationship under diverse contexts are necessary to help clarify this issue. This study explored the association between specific air pollutants (NO₂, SO₂, PM₁₀, PM_2.5, CO and O₃) and suicide incidence in four Colombian cities after adjusting for climatic variables and holidays.

METHODS

A time series of daily suicides among men and women living in Bogota, Medellin, Cali and Bucaramanga was generated using information from the National Administrative Department of Statistics (DANE) for the years 2011-2014. At the same time, the average daily concentration of each air pollutant for each city was obtained from monitoring stations belonging to the National Air Quality Surveillance System. Using this information together, we generated conditional Poisson models (stratified by day, month and year) for the suicide rate in men and women, with air pollutants as the principal explanatory variable. These models were adjusted for temperature, relative humidity, precipitation and holidays.

RESULTS

No association was found between any of the examined pollutants and suicide: NO₂ (IRR:0.99, 95% CI: 0.95-1.04), SO₂ (IRR:0.99, 95% CI: 0.98-1.01), PM₁₀ (IRR:0.99, 95% CI:0.95-1.03), PM_2.5 (IRR:1.01, 95% CI: 0.98-1.05), CO (IRR:1.00, 95% CI:1.00-1.00) and O₃ (IRR: 1.00, 95% CI: 0.96-1.04). In the same way, no association was found in stratified models by sex and age group neither in lagged and cumulative effects models.

CONCLUSIONS

After adjusting for major confounding factors, we found no statistically significant association between air pollution and suicide in Colombia. These "negative" results provide further insight into the current discussion regarding the existence of such a relationship.

Long-term exposure to ambient air pollutants and mental health status: A nationwide population-based cross-sectional study

There is a suspected but unproven association between long-term exposure to ambient air pollution and mental health. The aim of this study is to investigate the association between long-term exposure to ambient air pollution and subjective stress, depressive disorders, health-related quality of life (QoL) and suicide. We selected 124,205 adults from the Korean Community Health Survey in 2013 who were at least 19 years old and who had lived in their current domiciles for > five years. Based on the computer-assisted personal interviews to measure subjective stress in daily life, EuroQoL-5 dimensions, depression diagnosis by a doctor, suicidal ideation, and suicidal attempts, we evaluated the risk of mental disorders using multiple logistic regression analysis according to the quartiles of air pollutants, such as particulate matter <10μm (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), and sulfur dioxide, using yearly average concentration between August 2012 and July 2013. The prevalence of high stress, poor QoL, depressiveness, diagnosis of depression, and suicide ideation was positively associated with high concentrations of PM10, NO2, and CO after adjusting for confounding factors. Men were at increased risk of stress, poor QoL, and depressiveness from air pollution exposure than were women. The risk of higher stress or poor QoL in subjects < age 65 increased with air pollution more than did that in subjects ≥ age 65. Long-term exposure to ambient air pollution may be an independent risk factor for mental health disorders ranging from subjective stress to suicide ideation.

Advanced Daily Prediction Model for National Suicide Numbers with Social Media Data

OBJECTIVE

Suicide is a significant public health concern worldwide. Social media data have a potential role in identifying high suicide risk individuals and also in predicting suicide rate at the population level. In this study, we report an advanced daily suicide prediction model using social media data combined with economic/meteorological variables along with observed suicide data lagged by 1 week.

METHODS

The social media data were drawn from weblog posts. We examined a total of 10,035 social media keywords for suicide prediction. We made predictions of national suicide numbers 7 days in advance daily for 2 years, based on a daily moving 5-year prediction modeling period.

RESULTS

Our model predicted the likely range of daily national suicide numbers with 82.9% accuracy. Among the social media variables, words denoting economic issues and mood status showed high predictive strength. Observed number of suicides one week previously, recent celebrity suicide, and day of week followed by stock index, consumer price index, and sunlight duration 7 days before the target date were notable predictors along with the social media variables.

CONCLUSION

These results strengthen the case for social media data to supplement classical social/economic/climatic data in forecasting national suicide events.

Unexpected potential protective associations between outdoor air pollution and cataracts

Air pollution is one of the biggest public health issues, and the eye is continuously exposed to multiple outdoor air pollution. However, to date, no large-scale study has assessed the relationship between air pollutants and cataracts. We investigated associations between outdoor air pollution and cataracts in the Korean population. A population-based cross-sectional study was performed using data from the Korea National Health and Nutrition Examination Survey, including 18,622 adults more than 40 years of age. The presence of cataracts and their subtypes were evaluated by ophthalmologists. Air pollution data (levels of particulate matter, ozone, nitrogen dioxide, and sulfur dioxide) for the 2 years prior to the ocular examinations were collected from national monitoring stations. The associations of multiple air pollutants with cataracts were assessed by multivariate logistic regression analyses. Sociodemographic factors and previously known risk factors for cataracts were controlled as covariates (model 1 included sociodemographic factors, sun exposure, and behavioral factors, while model 2 further included clinical factors). Higher ozone concentrations were protectively associated with overall cataract which included all subtypes [single pollutant model: 0.003 ppm increase-model 1 (OR 0.89, p = 0.014), model 2 (OR 0.87, p = 0.011); multi-pollutant model: 0.003 ppm increase-model 1 (OR 0.80, p = 0.002), model 2 (OR 0.87, p = 0.002)]. Especially, higher ozone concentrations showed deeply protective association with nuclear cataract subtype [0.003 ppm increase-single pollutant model: model 2 (OR 0.84, p = 0.006), multi-pollutant model: model 2 (OR 0.73, p < 0.001)]. Higher tropospheric ozone concentrations showed protective associations with overall cataract and nuclear cataract subtype in the Korean population.

[Climate change - physical and mental consequences]

Climate change has already had a large influence on the human environmental system and directly or indirectly affects physical and mental health. Triggered by extreme meteorological conditions, for example, storms, floods, earth slides and heat periods, the direct consequences range from illnesses to serious accidents with injuries, or in extreme cases fatalities. Indirectly, a changed environment due to climate change affects, amongst other things, the cardiovascular system and respiratory tract, and can also cause allergies and infectious diseases. In addition, increasing confrontation with environmental impacts may cause negative psychological effects such as posttraumatic stress disorders and anxiety, but also aggression, distress and depressive symptoms. The extent and severity of the health consequences depend on individual pre-disposition, resilience, behaviour and adaptation.

Mortality risks from a spectrum of causes associated with wide-ranging exposure to fine particulate matter: A case-crossover study in Beijing, China

BACKGROUND

Exposure to fine particulate matter (≤2.5μm in aerodynamic diameter; PM_2.5) has been shown to be associated with an increased risk of mortality due to cardiovascular, respiratory, and other pulmonary diseases. However, fewer studies have investigated the relationship between ambient PM_2.5 and human mortality for a wider range of causes of death, or for more specific causes of death within these broader categories, especially at the high PM_2.5 concentrations currently experienced in Chinese megacities. Beijing, China, has a very large population and a wide range of PM_2.5 exposures, allowing a prime opportunity to estimate such risks across a broad spectrum of causes, including rarer causes of death.

OBJECTIVE

To estimate the relative risk of cause-specific mortality associated with PM_2.5 for a spectrum of causes of death, as well as characterize the time course of cause-specific mortality following PM_2.5 exposure, in a location where PM_2.5 concentrations are representative of common exposures in Chinese megacities.

METHODS

We collected daily data on mortality counts of Beijing residents and Beijing weather and air pollution measurements for January 1, 2009 to December 31, 2012. We used a time-stratified case-crossover study design to estimate the association between ambient PM_2.5 concentrations and risk of death from several broad causes of death and from more refined specific causes within these broader categories. Primary results were estimated for risks the day of and the day following exposure (lag 0-1), but the time pattern of associated risk was also explored up to seven days following exposure.

RESULTS

Increased concentrations of PM_2.5 were associated with increased risks at lag days 0-1 of all-cause mortality (0.26% increase per 10μg/m³; 95% confidence interval [CI]: 0.12%-0.39%), non-accidental deaths (0.25%; 95% CI: 0.11%-0.38%), circulatory deaths (0.39%; 95% CI: 0.21%-0.59%), respiratory deaths (0.43%; 95% CI: 0.05%-0.81%), intentional self-harm deaths (1.94%; 95% CI: 0.19%-3.73%) and nervous system deaths (0.9%; 95% CI: -0.2%-2%), although the observed increase was not statistical significant for the final one rarer cause of death. In addition to these five broad death outcomes, risk also increased following PM_2.5 exposure at lag days 0-1 for deaths from several specific causes, including most of the specific circulatory causes considered. The largest observed increased risk by far was for one of the rarest causes of death considered, extrapyramidal and movement disorders (2.35%; 95% CI: 0.03%-4.72%).

CONCLUSIONS

This study indicates that exposure to PM_2.5 in a study location more representative of exposures in developing cities is associated with an increased risk of mortality from broad range of causes of death, including some causes rarely studied previously in association with PM_2.5 exposure.

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.

Monthly variations in aneurysmal subarachnoid hemorrhage incidence and mortality: Correlation with weather and pollution

BACKGROUND AND PURPOSE

Although the effect of weather and air pollution on the occurrence of subarachnoid hemorrhage (SAH) has been investigated, results have remained inconsistent. The present study aimed to determine the seasonality of aneurysmal subarachnoid hemorrhage occurrence and mortality.

METHODS

We used the National Inpatient Sample database to evaluate the effect of meteorological factors and air pollutants on patients with subarachnoid hemorrhage in Korea between 2011 and 2014. Monthly variations in SAH occurrence and mortality were analyzed using locally weighted scatter plot smoothing curves. Multivariate Poisson generalized linear regression models were used to evaluate potential independent meteorological and pollutant variables associated with SAH occurrence and mortality.

RESULTS

In total, 21,407 patients who underwent clip or coil treatment owing to aneurysmal SAH in Korea from January 1, 2011, to December 31, 2014, were included. The crude incidence rate of SAH in Korea was 10.5 per 100,000 people per year. An approximately 0.5% lower risk of SAH was observed per 1°C increase in mean monthly temperature (relative risk, 0.995; 95% confidence interval [CI], 0.992-0.997; p < 0.001), while an approximately 2.3% higher risk of SAH was observed per 1°C increase in mean monthly diurnal temperature.

CONCLUSIONS

We showed distinct patterns of seasonal and monthly variation in the occurrence and mortality of SAH. Our findings suggest that meteorological factors may play an important role in monthly variations in the occurrence of aneurysmal SAH.

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.

Airborne pollen and suicide mortality in Tokyo, 2001-2011

Prior research has indicated that pollen might be linked to suicide mortality although the few studies that have been undertaken to date have produced conflicting findings and been limited to Western settings. This study examined the association between the level of airborne pollen and suicide mortality in Tokyo, Japan in the period from 2001 to 2011. The daily number of suicide deaths was obtained from the Japanese Ministry of Health, Labour and Welfare, with pollen data being obtained from the Tokyo Metropolitan Institute of Public Health. A time-stratified case-crossover study was performed to examine the association between different levels of pollen concentration and suicide mortality. During the study period there were 5185 male and 2332 female suicides in the pollen season (February to April). For men there was no association between airborne pollen and suicide mortality. For women, compared to when there was no airborne pollen, the same-day (lag 0) pollen level of 30 to <100 grains per cm² was associated with an approximately 50% increase in the odds for suicide (e.g. 30 to <50 grains per cm²: odds ratio 1.574, 95% confidence interval 1.076-2.303, p=0.020). The estimates remained fairly stable after adjusting for air pollutants and after varying the cut-points that defined the pollen levels. Our results indicate that pollen is associated with female suicide mortality in Tokyo.

Global trends in suicide epidemiology

PURPOSE OF REVIEW

Suicide is a major cause of mortality accounting for nearly 1 million deaths globally per year. Suicide occurs throughout the lifespan; therefore, large epidemiological samples are needed to identify patterns in suicide death. This review examines emerging evidence relating to risk and protective factors as well as preventive measures for suicide.

RECENT FINDINGS

The global financial crisis, natural disasters, air pollution and second-hand smoke have all been associated with increased suicide rates. At an individual level, past self-harm, parental loss or separation and younger age relative to classmates all confer risk. There is mixed evidence for religious affiliation and lithium levels in drinking water as protective factors. Means restriction strategies including barriers at suicide hotspots, firearms restrictions and limiting access to both pesticides and charcoal have all prevented suicide. Other interventions with recent evidence include improvements in mental health systems, selective serotonin reuptake inhibitor (SSRI) and lithium treatment in youth and mental health awareness in schools.

SUMMARY

The evidence for risk/protective factors for suicide continues to grow and, more importantly, numerous prevention efforts continue to demonstrate positive outcomes. Public policy experts should attend to the environmental and social determinants of health when devising suicide prevention programs, and the evidence-based prevention strategies identified here should be implemented more broadly.

Ambient air pollution and suicide in Tokyo, 2001-2011

BACKGROUND

Some evidence suggests an association may exist between the level of air pollution and suicide mortality. However, this relation has been little studied to date. The current study examined the association in Tokyo, Japan.

METHODS

Suicide mortality data for Tokyo for the 11-year period 2001-2011 were obtained together with data on four air pollutants: fine particulate matter (PM2.5), suspended particulate matter (SPM), sulphur dioxide (SO2) and nitrogen dioxide (NO2). A time-stratified case-crossover study design was used to examine the daily association between the level of air pollution and suicide mortality.

RESULTS

During the study period there were 29,939 suicide deaths. In stratified analyses an interquartile range (IQR) increase in the same-day concentration of NO2 was linked to increased suicide mortality among those aged under 30 (percentage change: 6.73%, 95% CI: 0.69-13.12%). An IQR increase in PM2.5 and SO2 was associated with a 10.55% (95% CI: 2.05-19.75%) and 11.47% (95% CI: 3.60-19.93%) increase, respectively, in suicide mortality among widowed individuals for mean exposure on the first four days (average lags 0-3). Positive associations were observed for the air pollutants in the summer although associations were reversed in autumn.

LIMITATIONS

We relied on monitoring data to approximate individual exposure to air pollutants.

CONCLUSIONS

Higher levels of air pollution are associated with increased suicide mortality in some population subgroups in Tokyo. Further research is needed to elucidate the mechanisms linking air pollutants and suicide in this setting.

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

BACKGROUND

Preventing suicide is a global imperative. Although the effects of social and individual risk factors of suicide have been widely investigated, evidence of environmental effects of exposure to air pollution is scarce. We investigated the effects of ambient air pollution on suicide mortality in Guangzhou, China during 2003-2012.

METHODS

A conditional logistic regression analysis with a time-stratified case-crossover design was performed to assess the effects of daily exposure to three standard air pollutants, including particulate matter less than 10 μm in aerodynamic diameter (PM10), sulphur dioxide (SO2) and nitrogen dioxide (NO2), on suicide mortality, after adjusting for the confounding effects of daily mean temperature, relative humidity, atmospheric pressure and sunshine duration. Further analyses were stratified by season, gender, age group, educational attainment and suicide type.

RESULTS

Between 2003 and 2012, there were a total of 1 550 registered suicide deaths in Guangzhou. A significant increase in suicide risk were associated with interquartile-range increases in the concentration of air pollutant, with an odds ratio of 1.13 (95 % confidence interval (CI): 1.01, 1.27) and 1.15 (95 % CI: 1.03, 1.28) for PM10 and NO2 at lag 02, and 1.12 (95 % CI: 1.02, 1.23) for SO2 at lag 01, respectively. The suicide risks related to air pollution for males and people with high education level were higher than for females and those with low education level, respectively. Significant air pollution effects were found on violent suicide mortality and in cool season but not on non-violent suicide mortality or in warm season.

CONCLUSIONS

Suicide risk was positively associated with ambient air pollution levels. This finding would provide important information for the health impact assessment of air pollution and for the development of effective strategies and interventions for the prevention of suicide.