INTRODUCTION: Pesticide ingestion is among the leading methods for suicide in Taiwan and worldwide. Paraquat, a commonly used herbicide, is highly lethal when ingested and the leading pesticide involved in suicide in Taiwan. The sale of paraquat dropped markedly in 2019 after Taiwan banned its import and processing in February 2018. A recent study showed a 37% reduction in Taiwan's pesticide suicide rate in 2019. We investigated the impact on suicide of Taiwan's complete ban on the sale and use of paraquat from February 2020.
METHODS: Suicide data among people aged 15 years or above were extracted from Taiwan's national cause-of-death data files (2011-2020). Negative binomial regression was used to estimate the rate ratios for suicide in 2020 between the observed rates and the expected rates according to pre-ban linear trends (2011-2017).
RESULTS: The was an estimated 44% (95% confidence interval 33-53%) reduction in the pesticide suicide rate in 2020, mainly attributable to a 74% (66-81%) reduction in the paraquat suicide rate. The overall suicide rates decreased 7% (1-13%) in 2020. No evidence was found for a shift from pesticide suicides to suicides using other methods. Larger reductions in the number of pesticide suicides were found in rural areas, males, and middle-aged and older people than their counterparts. No obvious change in the yields of major crops was found after the paraquat ban.
CONCLUSION: Suicide rates of paraquat and pesticide poisoning continued to decrease in 2020 after the complete ban of paraquat was implemented. The ban on highly hazardous pesticides can prevent impulsive pesticide suicides and is an effective suicide prevention strategy.
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背景：農藥中毒在臺灣與全球是導致自殺身亡的主要方法之一，常用除草劑巴拉刈攝入人體會導致高致死率，在臺灣曾是造成死亡的主要農藥。臺灣於2018年2月禁止巴拉刈的加工及輸入，近期研究指出次年（2019）的農藥自殺率下降37%。本研究評估2020年2月全面禁用巴拉刈之銷售與使用對該年臺灣自殺率的影響。方法：15歲以上的自殺數據來自臺灣死因統計檔（2011-2020）。使用負二項迴歸模型以巴拉刈禁用前（2011-2017）的自殺率趨勢，估算2020年實際自殺率相對於預期自殺率的比值（rate ratio [RR]）。結果：2020年農藥中毒自殺率較預期減少44%（95%信賴區間33-53%），主因為巴拉刈自殺率減少74%（66-81%），同年整體自殺率也下降7%（1-13%），農藥中毒自殺的減少並無轉移到其它自殺方法的傾向。農藥中毒自殺人數下降較明顯的包括非都會地區、男性，及中高齡者族群。主要農作物生產量於巴拉刈禁用後無明顯變化。結論：臺灣於2020年全面禁用巴拉刈後，巴拉刈與整體農藥自殺率持續較預期下降。禁用高毒性農藥可以減少衝動下的農藥中毒自殺，是預防自殺死亡的有效策略。