One in four suicides in rural areas of Taiwan were the result of pesticide poisoning prior to 2018, with one highly toxic pesticide accounting for a significant share of deaths, according to a new study.
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The study, led by researchers at the National Taiwan University, and supported by the Centre for Pesticide Suicide Prevention, aimed to examine the burden of suicides by pesticide poisoning before the 2018-2020 paraquat ban.
The research had a particular focus on deaths from paraquat – a highly lethal pesticide, which has already been banned in over 70 countries due to its high toxicity and risk to human health.
Taiwan banned paraquat in two stages between 2018 – 2020. However, prior to the ban there had been no national studies on the epidemiology of paraquat’s use for suicide. This information is important for measuring and understanding the impact of the ban.
The study investigated the burden, trends, geographic variations, and demographic characteristics of pesticide and paraquat suicides in Taiwan prior to the ban. Evidence was obtained from Taiwan’s cause-of-death mortality data files for 1987, 1992, 1997 and 2002-2017.
The researchers found that pesticide poisoning was a leading cause of suicide in Taiwan, responsible for 13% of all suicides (2002-2017). The proportion was highest in rural areas, where more people work in farming and have greater access to pesticides, with pesticide poisoning accounting for 24% of all suicides.
In each year studied, paraquat was found to be the leading pesticide involved in suicides. Overall, at least 4% of all suicides in Taiwan were found to be a result of paraquat poisoning, rising to 8% in rural areas. When analysis was limited to cases involving a known pesticide – excluding cases where the pesticide was unspecified – paraquat accounted for approximately 60% of pesticide suicides.
These findings provide an important baseline for assessing the impact of Taiwan’s paraquat ban. Given the high number of deaths from paraquat poisoning prior to the ban, the study suggests that the ban could be effective in preventing a significant number of deaths.
Professor Shu-Sen Chang, who led the study at the National Taiwan University, said:
“One of the most striking findings was the geographical inequality in pesticide suicide across Taiwan. Before the paraquat ban, pesticides were involved in around one in four suicide deaths in rural areas, and paraquat alone in around one in twelve.
“This shows how access to highly lethal means can shape suicide patterns in a population. Limiting access to such means can therefore be an important part of suicide prevention, particularly in rural areas where the burden of pesticide suicide was greatest.”
Responding to findings, Professor Michael Eddleston, Director of the Centre for Pesticide Suicide Prevention said:
“It is important that regulatory action to limit access to pesticides is evidence-based and its impact can be measured. We already know from international evidence that a ban on paraquat – a highly lethal pesticide for which there is no known antidote – can be highly effective in saving lives.
“Thanks to the research team at the National Taiwan University, we now know the extent to which pesticides, particularly paraquat, have been responsible for suicides in Taiwan. Given the significant numbers involved, we would expect to see a noticeable reduction in deaths as the impact of the ban becomes apparent.”
The study “The burden of suicide by paraquat poisoning in Taiwan (1987–2017): trends, geographic variations, and demographic characteristics” is published in BMC Public Health.
Further reading
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Taiwan’s paraquat ban has led to a fall in pesticide suicides, early analysis shows
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