A community-based cluster randomised trial of safe storage to reduce pesticide self-poisoning in rural Sri Lanka: study protocol

Melissa Pearson, Flemming Konradsen, David Gunnell, Andrew H Dawson, Ravi Pieris, Manjula Weerasinghe, Duleeka W Knipe, Shaluka Jayamanne, Chris Metcalfe, Keith Hawton, A Rajitha Wickramasinghe, W Atapattu, Palitha Bandara, Dhammika de Silva, Asanga Ranasinghe, Fahim Mohamed, Nicholas A Buckley, Indika Gawarammana, Michael Eddleston, Melissa Pearson, Flemming Konradsen, David Gunnell, Andrew H Dawson, Ravi Pieris, Manjula Weerasinghe, Duleeka W Knipe, Shaluka Jayamanne, Chris Metcalfe, Keith Hawton, A Rajitha Wickramasinghe, W Atapattu, Palitha Bandara, Dhammika de Silva, Asanga Ranasinghe, Fahim Mohamed, Nicholas A Buckley, Indika Gawarammana, Michael Eddleston

Abstract

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.

Trial registration: ClinicalTrials.gov NCT01146496.

Figures

Figure 1
Figure 1
Household storage of pesticides in pilot studies in Sri Lanka. Left - % of households storing pesticides safely in or around their house in the five studies. Right - Comparison of the % of households in Study A storing pesticides in their household (top line) and the % storing pesticides safely locked up (bottom line) after provision of a safe storage container. The hatched area represents households storing unlocked pesticides. Note, there was no change in the number of households that stored pesticides in the house without locking them away. Instead, the intervention markedly increased the absolute number of households storing pesticides in the house, potentially increasing the risk of poisoning if the compliance with locking them away fell away over time.
Figure 2
Figure 2
Distribution of study areas and hospitals in the Anuradhapura District of Sri Lanka. Five study areas divisional secretariats (Thambuthegama, Talawa, Galnewa, Rajanganaya and Nochchiyagama) and additional neighbouring division of Ipalogama where additional households may be recruited. The map also shows the fifteen peripheral hospitals (Rural, District, Primary and Base hospitals) within, or neighbouring, the study area that are used to identify cases of poisoning and self-harm.
Figure 3
Figure 3
Safe storage device for agrochemicals in Sri Lanka. The UV-resistant plastic pesticide storage container to be used in this study. A) Device before installation: the metal bar at the base secures the device from theft. B) Device buried with two lids to protect the padlock from weather damage. C) Device can store several large and small bottles of pesticides. Copyright Ravi Peiris.

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Source: PubMed

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