Blood cholinesterase level and its association with neurobehavioral performance due to insecticide exposure among male cocoa farmers in Pahang and Perak, Malaysia

Background: Chlorpyrifos (group II) is an example of organophosphate (OP) insecticides used in cocoa farm that contains moderately hazardous substances that may be dangerous, toxic and can cause severe effects to human health. It is a concern considering cocoa plantations uses large amount of pesticides. There is a lack of study focusing on cocoa farmers’ exposure to organophosphate and data is needed to allow preventive measures to be planned and implemented in order to protect the health and safety of the workers in this specific agricultural sector.

Objective: This study aims to determine blood cholinesterase level due to exposure to organophosphate pesticides and identify its link with neurobehavioral performance of cocoa farmers in cocoa plantations across Perak and Pahang, Malaysia.

Method: This is a cross-sectional study among participants that includes cocoa farmers as the exposed group and fishermen as the comparison group. Structured questionnaire were administered to obtain background information and occupational usage of insecticides. Blood samples were collected via finger prick technique and seven tests of World Health Organization (WHO) Neurobehavioral Core Test Battery (NCTB) were used to measure the neurobehavioral performance of the respondents. Data collected were entered into statistical software and were analysed according to objectives.

Results: A total of 178 respondents were recruited in this study. This study had reversed results where the blood cholinesterase level of the comparison group was below than the normal range compared to the exposed group. The standard scores of Pursuit Aiming and Trail Making tests showed that the exposed group had significantly poorer performance than the comparison group. There was no significant correlation between the blood cholinesterase with neurobehavioral performance scores for the exposed group. Income, years of handling were significant predictor factors for Pursuit Aiming Test whereas age, use of gloves and education for Trail Making Test.

Conclusion: The findings of this study showed that neurobehavioral assessment conducted have provided insight into the early effects of OP pesticide exposures when results detected impairment of cocoa farmers’ motor steadiness and visual motor coordination. There is a need to encourage commitment of employers to protect workers through conducting medical surveillance, reviewing existing training modules, assist in the amendment of the existing guideline for use and provide adequate and suitable personal protective equipment for the use of the workers in order to fulfil the objectives of the Occupational Safety and Health Act.