Secular Change in Mortality from Suicide in Australia during the 20th Century

Abstract

To identify secular change in Australian suicide mortality over the period 1907-1998 and to seek possible explanations, a descriptive epidemiological study was conducted. Deaths due to suicide from 1907 to 1998 were identified according to the ICD-9. Trends in overall annual suicide mortality rates for all causes and individual causes were examined using the three-year moving average method, standardised by age and sex. Secular trends for mortality over the study period were examined in various age groups, using linear regression to test the slope. The results indicated that there has been a decline in overall age and sex standardised mortality from suicide over the study period. The death rate dropped from 15.2 per 100,000 in the early century to 13.9 per 100,000 in late century. Despite the overall decline, the female suicide mortality rates increased over the study period. Male suicide mortality rates were significantly higher than female rates over the study period (P<0.0001). Increased suicide rates were observed in the 15-24 and 25-44 year old age groups for both males and females. The group of 65+ year old females also had increased rates. Decreased rates were observed in both the male and female 45-64 year old age group and in the 65+ year old male age group. The three most common suicide methods used by males in 1907 were guns, poisoning and hanging, while for females they were drowning, hanging and poisoning. In 1998 they were changed to hanging, gas and guns for males and hanging, gas and drowning and poisoning (equally third) for females. These trends can be attributed to numerous factors such as economic crisis, world wars, the availability of suicide methods, a person's gender.