Suicides by pesticide ingestion in Pakistan and the impact of pesticide regulation

IntroductionSuicide is a major public health problem in Pakistan, accounting to approximately 19,331 deaths every year. Many are due to consumption of acutely toxic pesticides; however, there is a lack of national suicide data, limiting knowledge and potential for intervention. In this paper, we aimed to review the literature on pesticide self-poisoning in Pakistan to identify the most problematic pesticides in relation to national pesticide regulations.MethodsInformation on the currently registered and banned pesticides was obtained from Ministry of National Food Security and Research while data on pesticide import and use was extracted from FAOSTAT. We searched the following sources for articles and research papers on poisoning in Pakistan: Cumulative Index to Nursing and Allied Health (CINAHL), Google Scholar, Applied Social Sciences Index and Abstracts (ASSIA), Excerpta Medica (EMBASE), National Library of Medicine's MEDLINE (PUBMED), PS102YCHINFO and Pakmedinet.com using the search terms 'self-poisoning', 'deliberate self-harm', 'suicide', 'methods and means of suicide', 'organophosphate', 'wheat pill', 'aluminium phosphide', 'acute poisoning', OR 'pesticides', AND 'Pakistan'.ResultsAs of May 2021, 382 pesticide active ingredients (substances) were registered in Pakistan, of which five were WHO hazard class Ia (extremely hazardous) and 17 WHO hazard class Ib (highly hazardous). Twenty-six pesticides, four formulations, and seven non-registered pesticides had been banned, of which two were WHO class Ia and five Ib. We identified 106 hospital-level studies of poisoning conducted in Pakistan, of which 23 did not mention self-poisoning cases and one reported no suicidal poisoning cases. We found no community or forensic medicine studies. Of 52,323 poisoning cases identified in these papers, 24,546 [47%] were due to pesticides. The most commonly identified pesticide classes were organophosphorus (OP) insecticides (13,816 cases, 56%) and the fumigant aluminium phosphide (3 g 56% tablets, often termed 'wheat pills'; 686 cases, 2.7%). Few studies identified the particular pesticides involved or the resulting case fatality.ConclusionWe found pesticide poisoning to be a major cause of poisoning in Pakistan, with OP insecticides and the fumigant aluminium phosphide the main pesticides identified. Withdrawal of Class I pesticides (as proposed to occur nationally in 2022) and high concentration aluminium phosphide tablets should rapidly reduce suicidal deaths by reducing the case fatality for low-intention poisoning cases. National cause of death data and forensic toxicology laboratory data identifying the pesticides responsible for deaths will be important to assess impacts of the proposed national ban.