Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Differences in the characteristics of people who purchase pesticides from shops for self-harm versus those who use pesticides available in the domestic environment in Sri Lanka(Blackwell Publishing, 2023) Weerasinghe, M.; Jobe, L.; Konradsen, F.; Eddleston, M.; Pearson, M.; Jayamanne, S.; Hawton, K.; Gunnell, D.; Agampodi, S.OBJECTIVE: Data from South Asia indicate that for 15%-20% of suicide attempts, pesticides are purchased from shops; otherwise, pesticides are obtained from an individual's house or nearby environment. We aimed to investigate the difference between individuals who directly purchase pesticides from shops for suicide attempts and suicide deaths versus those related to accessing the pesticides from an individual's house or nearby environment. METHODS: We conducted two comparative studies in rural Sri Lanka: (1) non-fatal shop cases (n = 50) were survivors of self-poisoning with pesticides who ingested the pesticides after purchasing them from a shop; non-fatal domestic cases (n = 192) were survivors who accessed pesticides from their house or nearby environment. (2) fatal shop cases (n = 50) were individuals who died after ingesting pesticides they purchased for the act; fatal domestic cases (n = 102) were patients who died after ingesting pesticides they accessed at house or nearby environment. Logistic regression analysis was used to assess the characteristics which distinguished between the shop and domestic cases. RESULTS: Data indicate that 20.7% and 32.9% of individuals who used pesticides for suicide attempts and suicide deaths had purchased them from shops, respectively. Being a non-farmer was the main distinguishing characteristic of shop cases: adjusted odds ratios (AOR) 8.9, 95% confidence intervals (CI) 3.2-24.4 for non-fatal shop cases, and AOR 4.0, 95% CI 1.5-10.6 for fatal shop cases. Non-fatal shop cases also had higher suicide intent (AOR 3.0, CI 1.0-8.9), and ingesting an insecticide (AOR 4.8, CI 1.8-1.0-8.9) than non-fatal domestic cases. CONCLUSION: A high suicide intent of individuals who purchase pesticides for the event explains the high proportion of such fatal cases. Such high suicide intent makes the prevention implications difficult to spell out for those individuals who purchase pesticides for self-poisoning. However, our findings are valuable for clinicians to assess pesticide poisoning cases in hospitals.Item Factors associated with purchasing pesticide from shops for intentional self-poisoning in Sri Lanka(Blackwell Publishing Ltd, 2020) Weerasinghe, M.; Konradsen, F.; Eddleston, M.; Pearson, M.; Jayamanne, S.; Knipe, D.; Hawton, K.; Gunnell, D.; Agampodi, S.ABSTRACT: Objective: In South Asia, up to one in five individuals who ingest pesticides for self-poisoning and survive purchased them from a shop immediately prior to the event. Thus far, no research has taken place to determine whether interventions implemented through the pesticide sellers might be acceptable or effective, despite the hundreds of thousands of such risk purchases each year. We aimed to investigate factors associated with purchasing pesticides for self-poisoning in Sri Lanka. METHODS: We used a case–control study. Cases (n = 50) were individuals who ingested pesticides after purchasing them for the act, and controls (n = 200) were customers who bought pesticides but did not use them for self-harm. Logistic regression analysis was used to assess socio-demographic and purchase-specific risk factors. RESULTS: Alcohol intoxication (adjusted odds ratios [AOR] 36.5, 95% confidence intervals [CI] 1.7–783.4) and being a non-farmer AOR 13.3, 95% CI 1.8–99.6 were the main distinguishing factors when purchasing pesticides for self-poisoning. The positive predictive values were 93.3% (95% CI 68.0–99.8%) and 88.2% (95% CI 72.5–96.7%), respectively. One and/or other of these factors characterised 72.0% of cases but only 2.5% controls. CONCLUSION: While results need to be interpreted cautiously, sales restrictions to prevent alcohol-intoxicated persons and non-farmers purchasing pesticides for self-poisoning may be effective. © 2020 John Wiley & Sons Ltd AUTHOR KEYWORDS: pesticide shops; pesticides; self-poisoning; Sri Lanka; suicide. INDEX KEYWORDS: pesticide, environmental factor; pesticide; poisoning; regression analysis; risk factor, adult; alcohol consumption; alcohol intoxication; Article; automutilation; case control study; controlled study; female; human; major clinical study; male; predictive value; purchasing; self poisoning; sex difference; social status; Sri Lanka, Sri LankaItem Socioeconomic position and suicidal behaviour in rural Sri Lanka: a prospective cohort study of 168,000+ people.(Springer International, 2019) Knipe, D. W.; Gunnell, D.; Pieris, R.; Priyadarshana, C.; Weerasinghe, M.; Pearson, M.; Jayamanne, S.; Hawton, K.; Konradsen, F.; Eddleston, M.; Metcalfe, C.PURPOSE:Lower socioeconomic position (SEP) is associated with an increased risk of suicidal behaviour in high income countries, but this association is not established in low- and middle-income countries (LMIC). METHODS: We investigated the association of SEP with suicidal behaviour in a prospective cohort study of 168,771 Sri Lankans followed up for episodes of attempted suicide and suicide. SEP data were collected at baseline at the household and individual level at the start of the follow-up period. We used multilevel Poisson regression models to investigate the association of SEP at community, household and individual levels with attempted suicide/suicide. RESULTS: Lower levels of asset ownership [IRR (95% CI) suicide 1.74 (0.92, 3.28); attempted suicide 1.67 (1.40, 2.00)] and education [suicide 3.16 (1.06, 9.45); attempted suicide 2.51 (1.70, 3.72)] were associated with an increased risk of suicidal behaviour. The association of these measures of SEP and attempted suicide was stronger in men than women. Individuals living in deprived areas [1.42 (1.16, 1.73)] and in households with a young female head of household [1.41 (1.04, 1.93)] or a temporary foreign migrant [1.47 (1.28, 1.68)] had an elevated risk of attempted suicide. Farmers and daily wage labourers had nearly a doubling in risk of attempted suicide compared to other occupations. CONCLUSIONS: Improved employment opportunities, welfare and mental health support services, as well as problem-solving skills development, may help support individuals with poorer education, farmers, daily wage labourers, individuals in young female-headed households and temporary foreign migrant households.Item Potential interventions for preventing pesticide self-poisoning by restricting access through vendors in Sri Lanka(Hogrefe Publishing, 2018) Weerasinghe, M.; Konradsen, F.; Eddleston, M.; Pearson, M.; Jayamanne, S.; Gunnell, D.; Hawton, K.; Agampodi, S.BACKGROUND: In South Asia, up to one in five individuals who use pesticides for self-harm purchase them immediately prior to the event. AIMS: From reviewing the literature we proposed four interventions: (a) farmer identification cards (ID); (b) prescriptions; (c) cooling-off periods; and (d) training pesticide vendors. We aimed to identify the most promising intervention. Method: The study was conducted in Sri Lanka. We mapped stakeholders' interest and power in relation to each intervention, and followed this by a ranking exercise. Seven focus group discussions (FGDs) were conducted to assess facilitators and barriers to implementation. RESULTS:Vendor training was the most supported intervention, being ranked first by the stakeholders. The participants in the FGDs strongly supported training of vendors as it was seen to be easy to implement and was considered more convenient. Farmer IDs, prescriptions, and cooling-off periods were thought to have more barriers than facilitators and they were strongly opposed by end users (farmers and vendors), who would potentially block their implementation. LIMITATIONS: Cost considerations for implementing the proposed intervention were not considered. CONCLUSION: Training vendors might be the most appropriate intervention to restrict sales of pesticides to people at risk of suicidal behavior. This requires field testingItem Community-based cluster randomised trial of safe storage to reduce pesticide self-poisoning in rural Sri Lanka: study protocol(BioMed Central, 2011) Pearson, M.; Konradsen, F.; Gunnell, D.; Dawson, A.H.; Pieris, R.; Weerasinghe, M.; Knipe, D.W.; Jayamanne, S.; Metcalfe, C.; Hawton, K.; Wickremasinghe, A.R.; Atapattu, W.; Bandara, P.; de Silva, D.; Ranasinghe, A.; Mohamed, F.; Buckley, N.A.; Gawarammana, I.; Eddleston, M.A.BACKGROUND: The WHO recognises pesticide poisoning to be the single most important means of suicide globally. Pesticide self-poisoning is a major public health and clinical problem in rural Asia, where it has led to case fatality ratios 20-30 times higher than self-poisoning in the developed world. One approach to reducing access to pesticides is for households to store pesticides in lockable "safe-storage" containers. However, before this approach can be promoted, evidence is required on its effectiveness and safety. METHODS/DESIGN: A community-based cluster randomised controlled trial has been set up in 44,000 households in the North Central Province, Sri Lanka. A census is being performed, collecting baseline demographic data, socio-economic status, pesticide usage, self-harm and alcohol. Participating villages are then randomised and eligible households in the intervention arm given a lockable safe storage container for agrochemicals. The primary outcome will be incidence of pesticide self-poisoning over three years amongst individuals aged 14 years and over. 217,944 person years of follow-up are required in each arm to detect a 33% reduction in pesticide self-poisoning with 80% power at the 5% significance level. Secondary outcomes will include the incidence of all pesticide poisoning and total self-harm. DISCUSSION: This paper describes a large effectiveness study of a community intervention to reduce the burden of intentional poisoning in rural Sri Lanka. The study builds on a strong partnership between provincial health services, local and international researchers, and local communities. We discuss issues in relation to randomisation and contamination, engaging control villages, the intervention, and strategies to improve adherence.Item The Prevalence of previous self-harm amongst self-poisoning patients in Sri Lanka(Springer International, 2011) Mohamed, F.; Perera, A.; Wijayaweera, K.; Kularatne, K.; Jayamanne, S.; Eddleston, M.; Dawson, A.; Konradsen, F.; Gunnell, D.BACKGROUND: One of the most important components of suicide prevention strategies is to target people who repeat self-harm as they are a high risk group. However, there is some evidence that the incidence of repeat self-harm is lower in Asia than in the West. The objective of this study was to investigate the prevalence of previous self-harm among a consecutive series of self-harm patients presenting to hospitals in rural Sri Lanka. METHOD: Six hundred and ninety-eight self-poisoning patients presenting to medical wards at two hospitals in Sri Lanka were interviewed about their previous episodes of self-harm. RESULTS: Sixty-one (8.7%, 95% CI 6.7-11%) patients reported at least one previous episode of self-harm [37 (10.7%) male, 24 (6.8%) female]; only 19 (2.7%, 95% CI 1.6-4.2%) patients had made more than one previous attempt. CONCLUSION: The low prevalence of previous self-harm is consistent with previous Asian research and is considerably lower than that seen in the West. Explanations for these low levels of repeat self-harm require investigation. Our data indicate that a focus on the aftercare of those who attempt suicide in Sri Lanka may have a smaller impact on suicide incidence than may be possible in the West.Item Island-wide diversity in single nucleotide polymorphisms of the Plasmodium vivax dihydrofolate reductase and dihydropteroate synthetase genes in Sri Lanka(BioMed Central, 2007) Schousboe, M.L.; Rajakaruna, R.S.; Salanti, A.; Hapuarachchi, H.A.C.; Galappaththi, G.N.; Bygbjerg, I.C.; Amerasinghe, P.H.; Konradsen, F.; Alifrangis, M.BACKGROUND: Single nucleotide polymorphisms (SNPs) in the Plasmodium vivax dihydrofolate reductase (Pfdhfr) and dihydropteroate synthetase(Pvdhps) genes cause parasite resistance to the antifolate drug combination, sulphadoxine/pyrimethamine (SP). Monitoring these SNPs provide insights into the level of drug pressure caused by SP use and presumably other antifolate drugs. In Sri Lanka, chloroquine (CQ) with primaquine (PQ) and SP with PQ is used as first and second line treatment, respectively, against uncomplicated Plasmodium falciparum and/or P. vivax infections. CQ/PQ is still efficacious against P. vivax infections, thus SP is rarely used and it is assumed that the prevalence of SNPs related to P. vivax SP resistance is low. However, this has not been assessed in Sri Lanka as in most other parts of Asia. This study describes the prevalence and distribution of SNPs related to P. vivax SP resistance across Sri Lanka. SUBJECTS AND METHODS: P. vivax-positive samples were collected from subjects presenting at government health facilities across nine of the major malaria endemic districts on the island. The samples were analysed for SNPs/haplotypes at codon 57, 58, 61 and 117 of the Pvdhfr gene and 383, 553 and 585 of the Pvdhps gene by applying PCR followed by a hybridization step using sequence specific oligonucleotide probes (SSOPs) in an ELISA format. RESULTS: In the study period, the government of Sri Lanka recorded 2,149 P. vivax cases from the nine districts out of which, 454 (21.1%) blood samples were obtained. Pvdhfr haplotypes could be constructed for 373 of these. The FSTS wild-haplotype was represented in 257 samples (68.9%), the double mutant LRTS haplotype was the most frequently observed mutant (24.4%) while the triple mutation (LRTN) was only identified once. Except for two samples of the single mutated Pvdhps GAV haplotype, the remaining samples were wildtype. Geographical differences were apparent, notably a significantly higher frequency of mutant Pvdhfr haplotypes was observed in the Northern districts. CONCLUSION: Since SP is rarely used in Sri Lanka, the high frequency and diversity of Pvdhfr mutations was unexpected indicating the emergence of drug resistant parasites despite a low level of SP drug pressure.