A cross-ethnic comparison on incidence of suicide

Suicide rates vary widely across nations and ethnic groups. This study aims to explore potential factors contributing to inter-ethnic differences in suicide rates.

Study subjects came from a case-control psychological autopsy study conducted in Taiwan, including 116 consecutive suicides from two aboriginal groups and Taiwanese Han; 113 of them each matched with two living controls. Gender-, age- and method-specific suicide rates, population attributable fraction (PAF) of suicide for five major risk factors, help-seeking before suicide and emergency medical aid after suicide were compared between the three ethnic groups.

One aboriginal group (the Atayal) had significantly higher adjusted rate ratios (RR) of suicide than the other aboriginal group (the Ami) [RR 0.20, 95% confidence intervals (CI) 0.12-0.34] and the Han (RR 0.26, 95% CI 0.16-0.40). Such differences can be explained by higher PAFs of suicide for three major risk factors (substance dependence, PAF 47.6%, 95% CI 25.5-64.2; emotionally unstable personality disorder, PAF 52.7%, 95% CI 32.8-69.0; family history of suicidal behaviour, PAF 43.5%, 95% CI 23.2-60.2) in this group than in the other two groups. This higher suicide rate was substantially reduced from 68.2/100 000 per year to 9.1/100 000 per year, comparable with the other two groups, after stepwise removal of the effects of these three risk factors. Suicide rates by self-poisoning were also significantly higher in this group than in the other two groups.

Higher rates of specific risk factors and use of highly lethal pesticides for suicide contributed to the higher suicide rate in one ethnic group in Taiwan. These findings have implications for developing ethnicity-relevant suicide prevention strategies.