Background: There has been a strong increase in the international movement of workers during the last few decades. As Thailand's economy has rapidly developed during the past 20 years, it has attracted growing numbers of laborers from the bordering countries of Myanmar, Lao PDR, and Cambodia. Numbers of migrant workers in Thai agriculture have risen to the extent that the sector's continued growth has become increasingly dependent on migrant workers.
Objective: The purpose of this study was to explore the factors that contribute to the development of symptoms of insecticide poisoning among immigrant agricultural workers in the eastern region of Thailand.
Methods: Data were collected via interviews (N = 891), and the levels of cholinesterase activity in the workers' blood were tested using reactive test strips.
Results: Only 4.4% of the workers had normal levels of cholinesterase activity and 75.1% had levels that were abnormal. Regarding factors that affect gastrointestinal symptoms of poisoning, being aged 45 to 50 increased the risk of developing gastrointestinal symptoms (odds ratio (OR): 2.51; 95% CI: 1.41-4.46), as did using a backpack spraying technique (OR: 3.74; 95% CI: 2.16-6.49) and having only moderate levels of self-protection behavior while spraying the insecticides (OR: 2.23; 95% CI: 1.16-4.29). Having an at risk level of cholinesterase activity increased the risk of gastrointestinal symptoms (OR: 3.25; 95% CI: 1.05-10.04) and the risk of respiratory symptoms (OR: 2.75; 95% CI: 1.17-6.44).
Conclusion: It is recommended that insecticide self-protection measures should be promoted and health monitoring should be implemented for migrant workers affected by high-risk insecticide use.
Keywords: Immigrant workers; Thailand; cholinesterase; farmworkers; pesticides; poisoning symptoms.