(PhysOrg.com) -- Suicide rates increase not only as a result of mental illness, but also when there are difficulties with breathing, according to two large Asian population studies that detected the effects of air pollution and asthma, an illness that itself is exacerbated by poor air conditions.
Changsoo Kim, M.D., Ph.D., and colleagues obtained air pollution measurements for seven cities in South Korea and examined relationships between the timing of particulate matter increases and the 4,341 suicides occurring in 2004. Short-term increases in airborne particles were associated with a 9 percent increase in suicide, with a 19 percent increase in suicide for people with cardiovascular disease. Data on suicides were obtained from a national database.
National suicide records were also used in a second study by Chian-Jue Kuo, M.D., M.S., and colleagues to link suicides in Taiwan over 12 years with cases of asthma in nearly 163,000 high school students. Adolescents with asthma were twice as likely to commit suicide as were teens without asthma, and those with more severe asthma had a higher suicide rate.
Both studies showed a temporal relationship-the suicides came after the asthma or air pollution spikes. In addition, the relationships to suicide were independent of psychiatric illness.
The studies appear on July 15 at AJP in Advance , the online advance edition of The American Journal of Psychiatry (AJP), the official journal of the American Psychiatric Association. Funding for the Kim study was received from the Ministry of Environment, Republic of Korea.
Funding for the Kuo study was received from the Environmental Protective Administration, National Health Research Institutes, Kaohsiung Medical University, National Science Council, Chungshan Medical University Hospital, and Taipei City Hospital in Taiwan and from the National Institute of Mental Health in the U.S.
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More information: Journal paper: ajp.psychiatryonline.org/cgi/content/abstract/appi.ajp.2010.09101455v1