Effectiveness of household lockable pesticide storage to reduce pesticide self-poisoning in rural Asia: a community-based, cluster-randomised controlled trial

Background: Agricultural pesticide self-poisoning is a major public health problem in rural Asia. The use of ‘safer’ household pesticide storage has been promoted to prevent deaths but there is no evidence of effectiveness. We aimed to test the effectiveness of lockable household containers on preventing pesticide self-poisoning.

Methods: We performed a community-based cluster randomised controlled trial in Sri Lanka with 180 rural villages allocated to intervention (n=90) or usual practice control (n=90). Intervention arm households using pesticides were given a lockable storage container. Further interaction was restricted to community posters and six-monthly reminders during routine community meetings. Primary outcome was the incidence of pesticide self-poisoning in people aged 14-years and over during a three-year follow-up. Secondary outcomes included the incidence of pesticide poisoning, all self-harm (fatal and non-fatal), all self-poisoning, and paediatric pesticide poisoning.

Findings: We enrolled 223,861 people in 53,382 households; 20,200 household pesticide storage containers were distributed. After three-years, surveys of 13,999 (26.2%) households indicated that 53.3% and 5.0% of intervention and control households, respectively, were locking pesticides away at least some of the time. The intervention had no significant effect on pesticide self-poisoning: intervention 293.3 vs. control 318.0 per 100,000 years of follow-up (RR 0.93 [95%CI 0.80-1.08], p=0.33). There was no evidence that the intervention was more effective during the first year, when appropriate usage was maximal. We found no evidence of switching from pesticide self-poisoning to other forms of self-harm, with no significant difference in fatal (intervention 82 vs control 67, RR 1.22 [0.88-1.68]) or non-fatal (1135 vs 1153, RR 0.97 [0.86-1.08]) self-harm events involving all methods.

Interpretation: We found no evidence that means reduction through improved household pesticide storage reduces pesticide-self-poisoning. Other approaches, particularly removal of highly hazardous pesticides from agricultural practice, are likely to be more effective for suicide prevention in rural Asia.