Melbourne School of Population Health, The University of Melbourne, Melbourne, Australia.
PLoS One. 2012;7(9):e44565. doi: 10.1371/journal.pone.0044565. Epub 2012 Sep 5.
To investigate the epidemiology of a steep decrease in the incidence of suicide deaths in Australia.
National data on suicide deaths and deliberate self-harm for the period 1994-2007 were obtained from the Australian Institute of Health and Welfare. We calculated attempt and death rates for five major methods and the lethality of these methods. Negative binomial regression was used to estimate the size and significance of method-specific time-trends in attempts and lethality.
Hanging, motor vehicle exhaust and firearms were the most lethal methods, and together accounted for 72% of all deaths. The lethality of motor vehicle exhaust attempts decreased sharply (RR = 0.94 per year, 95% CI 0.93-0.95) while the motor vehicle exhaust attempt rate changed little; this combination of motor vehicle exhaust trends explained nearly half of the overall decline in suicide deaths. Hanging lethality also decreased sharply (RR = 0.96 per year, 95% CI 0.956-0.965) but large increases in hanging attempts negated the effect on death rates. Firearm lethality changed little while attempts decreased.
Declines in the lethality of suicide attempts-especially attempts by motor vehicle exhaust and hanging-explain the remarkable decline in deaths by suicide in Australia since 1997.
调查澳大利亚自杀死亡人数急剧下降的流行病学情况。
从澳大利亚卫生福利研究所获得了 1994-2007 年期间自杀死亡和故意自残的国家数据。我们计算了五种主要方法的尝试率和死亡率，以及这些方法的致命性。使用负二项式回归来估计特定方法的尝试和致命性随时间的变化幅度和显著性。
上吊、汽车尾气和枪支是最致命的方法，共占所有死亡人数的 72%。汽车尾气尝试的致命性急剧下降（RR = 0.94/年，95%CI 0.93-0.95），而汽车尾气尝试率变化不大；这种汽车尾气趋势的结合解释了自杀死亡人数总体下降的近一半。上吊的致命性也急剧下降（RR = 0.96/年，95%CI 0.956-0.965），但上吊尝试的大量增加抵消了对死亡率的影响。枪支的致命性变化不大，而尝试次数减少。
自杀尝试致命性的下降——尤其是汽车尾气和上吊自杀的尝试——解释了自 1997 年以来澳大利亚自杀死亡人数的显著下降。
