Sri Lanka's pesticide regulations have contributed to one of the greatest falls in suicide rates ever seen in the world. Sri Lanka has reduced its suicide rate by 70% (or 93,000 lives) through a series of regulation of pesticides since 1995 (Knipe et al. The Lancet Global Health). Having peaked at 57 per 100 000 population in the early 1990s, its incidence is now 17 per 100 000 each year and continuing to fall. However, removal of problematic pesticides from agriculture by regulation then results in other pesticides becoming popular in agriculture and for self-harm. Therefore, there is a need to continue to monitor pesticide suicides to identify problematic replacements in a timely manner.
CPSP is analyzing recent secondary data on suicides collected as part of a cluster randomized controlled trial in the south-west of North Central Province (NCP) of Sri Lanka to identify key pesticide(s) responsible for suicides following the 2008-2014 regulation with the aim of reducing deaths through future regulations.
Pesticide regulations need to be carefully planned due to potential adverse effects on agricultural output and costs. However, previous studies in Sri Lanka (Manuweera et al, Environmental Health Perspectives), Bangladesh (Chowdhury et al, International Journal of Epidemiology) and South Korea (Cha et al, International Journal of Epidemiology) have shown no evidence of pesticide bans resulting in reduced agricultural yield and/or increased input costs to the farmer. CPSP is now investigating the impact on agricultural yield and input costs of the 2008-11 pesticide bans in Sri Lanka.
At the same time, CPSP is also in discussion with the Sri Lankan Pesticide Technical Advisory Committee about the possibility of setting up a cluster randomised controlled trial across the country to accurately identify the effects of pesticide bans on both agriculture and health. In such a study, the pesticides would be withdrawn from shops in half (12.5) of Sri Lanka's 25 districts over around 6 months in collaboration with the pesticide companies. The health and agriculture effects of this regulation would be carefully followed up, identifying whether the regulation prevents deaths from pesticide poisoning and whether it affects agricultural yield. Such a trial offers the first opportunity worldwide to prospectively and rigorously study the holistic effects of pesticide regulation on both health and agriculture in a middle-income country. Its results should be of value to the WHO, FAO, and governments across agricultural lands in setting policy for pesticide regulation.
Knipe DW, Gunnell D, Eddleston M. Preventing deaths from pesticide self-poisoning-learning from Sri Lanka's success. The Lancet Global health 2017; 5: e651-2.
Manuweera G, Eddleston M, Egodage S, Buckley NA. Do targeted bans of insecticides to prevent deaths from self-poisoning result in reduced agricultural output? Environmental Health Perspectives 2008; 116: 492-5.
Chowdhury FR, Dewan G, Verma VR, et al. Bans of WHO Class I Pesticides in Bangladesh-Suicide Prevention without Hampering Agricultural Output. International Journal of Epidemiology 2017; published online Aug 18. DOI:10.1093/ije/dyx157.
Cha ES, Chang S-S, Gunnell D, Eddleston M, Khang Y-H, Lee WJ. Impact of paraquat regulation on suicide in South Korea. International Journal of Epidemiology 2016; 45: 470-9.