Ban on paraquat, a commonly used weed-killer that is highly toxic to humans, in South Korea in 2011-2012 was followed by a reduction in suicide by pesticide poisoning, and annual number of pesticide suicide averaged 2033 over 1991-2012, but there could be an underestimation of 15-31 percent. These are the main results in two studies conducted by an international research team that includes Dr. Shu-Sen Chang at National Taiwan University (NTU) and Professor Won Jin Lee at Korea University. These findings have been published in two papers in the April issue of International Journal of Epidemiology (2016) and the June issue of Injury Prevention (2016), respectively.
[Photo: Dr. Shu-Sen Chang and Professor Won Jin Lee, who leads the Korean team based at College of Medicine, Korea University]
“Pesticide ingestion is among the most commonly used suicide methods globally, and many of these deaths occur in rural areas of South and East Asia. There is an urgent need to identify the true burden of suicide using this method and prevention strategies with evidence base. This may have important impact on the global and regional burden of suicide.” says Dr. Chang, the second author of the first paper and co-corresponding author of the second paper. Dr. Chang is an assistant professor at the Institute of Health Behaviors and Community Sciences, College of Public Health, NTU.
In the first paper, the authors estimated change in South Korea’s pesticide suicide rate in 2013, compared with those expected based on trends in 2003-11, to investigate the impact of a ban on paraquat in 2011-2012. They found a 37 percent reduction, corresponding to 847 fewer pesticide suicides in 2013. There was no increase in suicide using other methods and no change in crop yield.
In the second paper, the authors found similar sociodemographic profiles in certified deaths by pesticide ingestion and those classified as undetermined deaths/injuries by poisoning using pesticides and suicides/undetermined deaths/injuries by poisoning using unspecified chemicals. Annual number of pesticide suicide would increase 15-31 percent when assuming that 20-40 percent of deaths in these alternative cause-of-death categories are misclassified pesticide suicides.
In conclusion, Dr. Chang says, “South Korea’s data clearly show an effect of the paraquat ban to prevent suicide. Although the ban could not prevent suicidal behaviors, it could reduce mortality rate and save lives by giving those who have attempted suicide a second chance for life. Our data provide further empirical evidence for preventing strategies by restricting means or enhancing safety. They also highlight the importance of enhancing data quality and closely monitoring suicide trends.”