TY - JOUR

T1 - Air Pollution and Suicide in 10 Cities in Northeast Asia

T2 - A Time-Stratified Case-Crossover Analysis

AU - Kim, Yoonhee

AU - Ng, Chris Fook Sheng

AU - Chung, Yeonseung

AU - Kim, Ho

AU - Honda, Yasushi

AU - Guo, Yue Leon

AU - Lim, Youn-Hee

AU - Chen, Bing-Yu

AU - Page, Lisa A

AU - Hashizume, Masahiro

PY - 2018

Y1 - 2018

N2 - BACKGROUND: There is growing evidence suggesting an association between air pollution and suicide. However, previous findings varied depending on the type of air pollutant and study location.OBJECTIVES: We examined the association between air pollutants and suicide in 10 large cities in South Korea, Japan, and Taiwan.METHODS: We used a two-stage meta-analysis. First, we conducted a time-stratified case-crossover analysis to estimate the short-term association between nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter [aerodynamic diameter ≤10μm (PM10), aerodynamic diameter ≤2.5μm (PM2.5), and PM10–2.5] and suicide, adjusted for weather factors, day-of-week, long-term time trends, and season. Then, we conducted a meta-analysis to combine the city-specific effect estimates for NO2, SO2, and PM10 across 10 cities and for PM2.5 and PM10–2.5 across 3 cities. We first fitted single-pollutant models, followed by two-pollutant models to examine the robustness of the associations.RESULTS: Higher risk of suicide was associated with higher levels of NO2, SO2, PM10, and PM10–2.5 over multiple days. The combined relative risks (RRs) were 1.019 for NO2 (95% confidence interval [CI]: 0.999, 1.039), 1.020 for SO2 (95% CI: 1.005, 1.036), 1.016 for PM10 (95% CI: 1.004, 1.029), and 1.019 for PM10–2.5 (95% CI: 1.005, 1.033) per interquartile range (IQR) increase in the 0-1 d average level of each pollutant. We found no evidence of an association for PM2.5. Some of the associations, particularly for SO2 and NO2, were attenuated after adjusting for a second pollutant.CONCLUSIONS: Our findings suggest that higher levels of air pollution may be associated with suicide, and further research is merited to understand the underlying mechanisms. https://doi.org/10.1289/EHP2223.

AB - BACKGROUND: There is growing evidence suggesting an association between air pollution and suicide. However, previous findings varied depending on the type of air pollutant and study location.OBJECTIVES: We examined the association between air pollutants and suicide in 10 large cities in South Korea, Japan, and Taiwan.METHODS: We used a two-stage meta-analysis. First, we conducted a time-stratified case-crossover analysis to estimate the short-term association between nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter [aerodynamic diameter ≤10μm (PM10), aerodynamic diameter ≤2.5μm (PM2.5), and PM10–2.5] and suicide, adjusted for weather factors, day-of-week, long-term time trends, and season. Then, we conducted a meta-analysis to combine the city-specific effect estimates for NO2, SO2, and PM10 across 10 cities and for PM2.5 and PM10–2.5 across 3 cities. We first fitted single-pollutant models, followed by two-pollutant models to examine the robustness of the associations.RESULTS: Higher risk of suicide was associated with higher levels of NO2, SO2, PM10, and PM10–2.5 over multiple days. The combined relative risks (RRs) were 1.019 for NO2 (95% confidence interval [CI]: 0.999, 1.039), 1.020 for SO2 (95% CI: 1.005, 1.036), 1.016 for PM10 (95% CI: 1.004, 1.029), and 1.019 for PM10–2.5 (95% CI: 1.005, 1.033) per interquartile range (IQR) increase in the 0-1 d average level of each pollutant. We found no evidence of an association for PM2.5. Some of the associations, particularly for SO2 and NO2, were attenuated after adjusting for a second pollutant.CONCLUSIONS: Our findings suggest that higher levels of air pollution may be associated with suicide, and further research is merited to understand the underlying mechanisms. https://doi.org/10.1289/EHP2223.

KW - Air Pollutants/toxicity

KW - Air Pollution/adverse effects

KW - Environmental Exposure

KW - Humans

KW - Nitrogen Dioxide/toxicity

KW - Particulate Matter/toxicity

KW - Republic of Korea

KW - Suicide/statistics & numerical data

KW - Sulfur Dioxide/toxicity

U2 - 10.1289/EHP2223

DO - 10.1289/EHP2223

M3 - Journal article

C2 - 29529596

VL - 126

JO - Environmental Health Perspectives

JF - Environmental Health Perspectives

SN - 0091-6765

IS - 3

M1 - 037002

ER -