Ambient particulate matter as a risk factor for suicide.
OBJECTIVE
The authors assessed the relationship between exposure to ambient particulate matter and suicide in urban settings during a 1-year period.


METHODS
The association between particulate matter and suicide was determined using a time-stratified case-crossover approach in which subjects served as their own controls. All suicide cases (4,341) in 2004 that occurred in seven cities in the Republic of Korea were included. Hourly mean concentrations of particulate matter < or =10 microm in aerodynamic diameter (at 106 sites in the seven cities) and particulate matter < or =2.5 microm in aerodynamic diameter (at 13 sites in one city) were measured. The percent increase in suicide risk associated with an interquartile range increase in particulate matter was determined by conditional logistic regression analysis after adjusting for national holidays and meteorological factors. Subgroup analysis was performed after stratification by underlying disease (cardiovascular disease, diabetes mellitus, chronic obstructive pulmonary disease, cancer, and psychiatric illness).


RESULTS
The largest associations were a 9.0% increase (95% CI=2.4-16.1) and a 10.1% (95% CI=2.0-19.0) increase in suicide risk related to an interquartile range increase in particulate matter < or =10 microm (average of 0 to 2 days prior to the day of suicide) and particulate matter < or =2.5 microm (1 day prior to the day of suicide), respectively. Among individuals with cardiovascular disease, a significant association between particulate matter < or =10 microm (average of 0 to 2 days prior to the day of suicide) and suicide was observed (18.9%; 95% CI=3.2-37.0).


CONCLUSIONS
Conclusions: A transient increase in particulate matter was associated with increased suicide risk, especially for individuals with preexisting cardiovascular disease.
Kim
Changsoo
C
Department of Preventive Medicine and Institute for Environmental Research, Yonsei University College of Medicine, Seoul, Korea. preman@yuhs.ac
Jung
Sang Hyuk
SH
Kang
Dae Ryong
DR
Kim
Hyeon Chang
HC
Moon
Ki Tae
KT
Hur
Nam Wook
NW
Shin
Dong Chun
DC
Suh
Il
I
D000328:Adult; D000397:Air Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000401:mortality; D002423:Cause of Death / Q000639:trends; D002947:Cities / Q000453:epidemiology / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008685:Meteorological Concepts; D008875:Middle Aged; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012621:Seasons; D012923:Social Class; D013405:Suicide / Q000706:statistics & numerical data* / Q000639:trends
D052638:Particulate Matter