Classification of Suicide
Suicide cases were classified as violent and nonviolent, according to the classification system used in other studies (45–47). Poisoning, gas, and drowning were classified as nonviolent, whereas all other suicide methods were classified as violent.
Statistical Analysis
Statistical analyses were performed with SPSS version 11.5 (SPSS, Chicago) and Epi-Info version 6 (Centers for Disease Control, Atlanta). Chi-square analyses, Fisher’s exact test (two-tailed), and odds ratios (with the exact limit test to evaluate the 95% confidence interval [CI]) were used to compare categorical variables, and Student’s t test was used to analyze continuous variables. The joint effect of the independent variables, including age and the interactions of age and independent variables, were then analyzed with stepwise logistic regression.