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Objective: The authors assessed the relationship between exposure to ambient particulate matter and suicide in urban settings during a 1-year period. Method: 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 (4341) in 2004 that occurred in seven cities in the Republic of Korea were included. Hourly mean concentrations of particulate matter ≤10 pm in aerodynamic diameter (at 106 sites in the seven cities) and particulate matter ≤2.5 μm 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=24-16.1) and a 10.1% (95% CI-2.0-19.0) increase in suicide risk related to an interquartile range increase in particulate matter ≤10 μm (average of 0 to 2 days prior to the day of suicide) and particulate matter ≤2.5 μm (1 day prior to the day of suicide), respectively. Among individuals with cardiovascular disease, a significant association between particulate matter ≤10 μm (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: A transient increase in particulate matter was associated with increased suicide risk, especially for individuals with preexisting cardiovascular disease. [ABSTRACT FROM AUTHOR]

Objective In the Republic of Korea (ROK), soldiers stationed where there is a risk of contracting malaria have received antimalarial chemoprophylaxis since 1997. However, chemoprophylaxis may facilitate the development of drug resistance, and late primary attacks in individuals who have received chemoprophylaxis are becoming more frequent. We investigated the association between chemoprophylaxis and the epidemiological characteristics and effectiveness of treatment for re-emergent Plasmodium vivax malaria, using a nationwide malaria database. Methods Among soldiers at risk of malaria between 1999 and 2001, we reviewed all P. vivax malaria cases (1158) that occurred before 31 December 2003. Early and late primary attacks were defined as cases occurring ⩽ 2 or > 2 months after the last day of exposure to risk of malaria, respectively. Findings Of these cases, 634 (72.0%) had received chemoprophylaxis, and 324 (28.0%) had not. Cases occurred mostly in summer, with a peak in July-August. Stratification by chemoprophylaxis history revealed different times to onset. Early primary attacks were more prevalent in the group not receiving chemoprophylaxis, while in the group receiving chemoprophylaxis most cases were late primary attacks. Of the latter, 312 out of 461 (67.7%) did not take primaquine regularly. After treatment of the first attack, 14 (1.2%) of 1158 were re-treated; all re-treated cases were cured using the same doses and regimen used for the first treatment. Conclusion In ROK, the increase in late primary episodes of re-emergent P. vivax malaria is associated with the use of antimalarial chemoprophylaxis. [ABSTRACT FROM AUTHOR]