The Use of Self-reported Symptoms as a Proxy for Acute Organophosphate Poisoning Among Nepali Farmers

The Use of Self-reported Symptoms as a Proxy for Acute Organophosphate Poisoning Among Nepali Farmers: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

The purpose of this study is to evaluate self-reported symptoms as a proxy for acute organophosphate poisoning by examining self-reported acute organophosphate poisoning symptoms and PchE activity in response to occupational acute organophosphate exposure among farmers in Nepal.

Study Overview

• Status: Completed
• Conditions: Organophosphate Poisoning
• Intervention / Treatment: Other: Organophosphate; Other: Placebo

• Study Type: Interventional
• Enrollment (Actual): 42
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• male
• minimum age 18 years
• hand pressured backpack sprayer usage
• used to spray with moderately to extremely hazardous pesticides according to the World Health Organization's (WHO) Pesticide Hazard Classification

Exclusion Criteria:

• usual personal protective equipment use (respirator/mask with particulate filter, face shield, googles, gloves, boots, plastic poncho)
• unwilling to stay pesticide-free seven days prior to each of the two spray sessions
• medical conditions interfering with PchE activity (liver disease, acute infection, chronic malnutrition, heart attack, cancer, obstructive jaundice, inflammation caused by various diseases, or use of pyridostigmine drugs)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Group A; Initial spray session: organophosphate. Crossover spray session: placebo	Other: Organophosphate; Chlorpyrifos 50% plus cypermethrin 5%, WHO Class II: Moderately hazardous; Other: Placebo; Multineem, WHO Class U: Unlikely to present acute hazard in normal use; Other Names: Biopesticide
Other: Group B; Initial spray session: placebo. Crossover spray session: organophosphate	Other: Organophosphate; Chlorpyrifos 50% plus cypermethrin 5%, WHO Class II: Moderately hazardous; Other: Placebo; Multineem, WHO Class U: Unlikely to present acute hazard in normal use; Other Names: Biopesticide

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in self-reported acute organophosphate poisoning symptoms from baseline to follow up	Obtained using a structured questionnaire interview. The definition of symptoms was based on WHO's standardized list of clinical presentations of acute organophosphate poisoning.	Obtained just before (baseline) and 30 minutes after (baseline) each spray session
Change in Plasma Cholinesterase (PchE) activity from baseline to follow up	PchE activity was measured with a blood test using a Test-mate Che Cholinesterase System (Model 400) with a PchE Plasma Cholinesterase Assay Kit (Model 470).	Obtained just before (baseline) and 30 minutes after (baseline) each spray session

Collaborators and Investigators

• Sponsor: Bispebjerg Hospital
• Collaborators: Augustinus Fonden
• Investigators: Principal Investigator: Dea H. Kofod, MB, Department of Occupational and Environmental Medicine, Bispebjerg Frederiksberg Hospital, University of Copenhagen

Publications and helpful links

General Publications

• Kofod DH, Jors E, Varma A, Bhatta S, Thomsen JF. The use of self-reported symptoms as a proxy for acute organophosphate poisoning after exposure to chlorpyrifos 50% plus cypermethrin 5% among Nepali farmers: a randomized, double-blind, placebo-controlled, crossover study. Environ Health. 2016 Dec 13;15(1):122. doi: 10.1186/s12940-016-0205-1.

Study record dates

Study Major Dates

• Study Start: September 1, 2014
• Primary Completion (Actual): November 1, 2014
• Study Completion (Actual): November 1, 2014

Study Registration Dates

• First Submitted: July 14, 2016
• First Submitted That Met QC Criteria: July 17, 2016
• First Posted (Estimated): July 20, 2016

Study Record Updates

• Last Update Posted (Actual): July 28, 2023
• Last Update Submitted That Met QC Criteria: July 27, 2023
• Last Verified: July 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Chemically-Induced Disorders; Poisoning; Organophosphate Poisoning
• Other Study ID Numbers: 12205-01-57-02