Suicide by charcoal burning in Taiwan: implications for means substitution by a case-linkage study

Objective This study estimated the incidence of suicide mortality among suicide attempters in Taiwan and assessed the extent of means substitution among subjects with a non-fatal attempt and a subsequent fatal attempt during the study period. Methods A total of 5,261 suicide attempters registered in a surveillance system of a metropolitan catchment area from 2004 to 2005 were followed through 2005. Linkage to the death certification system revealed that 72 died by suicide. The association of completed suicide with the suicide method used at index attempt was examined using Cox proportional hazards regression. Incidence rate for the subsequent lethal suicide was estimated based on life tables. Results The 1-year incidence rate of suicide mortality was 0.017: 0.026 in males and 0.013 in females. There was a strong association between burning charcoal as the method used at the index attempt (relative hazard = 4.1, P < 0.001) and completed suicides. Those who used the method of burning charcoal at the index attempt frequently used the same means in a subsequent attempt leading to suicide mortality. However, a majority of suicide completers (59.1%) who died by burning charcoal had used a different method at their index attempt. Conclusions Persons who attempt suicide by charcoal burning are a high-risk group for completed suicide. Those who burned charcoal in a suicide attempt were likely to use the same method in a later lethal attempt, and charcoal burning was a frequent cause of death among those who used different methods in earlier attempts. Charcoal burning should be a target for suicide prevention efforts.