Mosquito control workers in Malaysia : is lifetime pesticide exposure associated with health impacts?

Use of pesticides has been linked to health effects among exposed workers. Organophosphate and pyrethroid pesticides are commonly used to control mosquito-borne diseases in Malaysia. This project aimed to estimate workers' lifetime exposure to pesticides and to examine the relationship between that exposure and health-related quality of life and neurobehavioural performances. A total of 158 workers who had regular contact with pesticides and 176 officebased workers were recruited to the study. Information on past exposure was collected through questionnaire and occupational history interview to help reconstruct workers' historical exposures. Personal inhalation and dermal exposure measurement were carried out to evaluate current pesticide exposure. Subjective inhalation and dermal models were used to allow the estimation of combined pesticide intake for each worker. Neurobehavioural performance was assessed using CANTAB® computerized tests. Total lifetime pesticides intake for exposed workers ranged from 0.006 g to 12,800 g (median (IQR) = 379 g (131, 794)). Estimated dermal exposure accounted for the majority of total lifetime intake of pesticides (median (IQR) = 369 g (128, 772)). After adjusting for age, education, smoking and BMI, exposure to pesticides was associated with lower physical health scores. All of the neurobehavioural performance test scores, with the exception of Reaction Time (RT) and Pattern Recognition Memory (PRM) tests, showed significant differences in relation to total lifetime pesticides intake after adjusting for age, education and smoking. The majority of pesticide-exposed workers indicated a positive awareness about pesticide risk. However, this awareness was not reflected to their selfprotective behaviours such as wearing PPE. Findings from this study suggest that lifetime pesticide intake is associated with physical health and cognitive impairment. It is not clear if this association is causal. Occupational hygiene control measures should focus on reducing the amount of pesticides workers get on their skin due to the high percentage of total intake arising from dermal exposure.