Department of Occupational Health and Safety, Faculty of Public Health, Mahidol University, 420/1 Rajvidhi Road, Bangkok 10400, Thailand
Sumate Pengpumkiat
Department of Occupational Health and Safety, Faculty of Public Health, Mahidol University, 420/1 Rajvidhi Road, Bangkok 10400, Thailand
Jutamanee Chungcharoen
Department of Occupational Health and Safety, Faculty of Public Health, Mahidol University, 420/1 Rajvidhi Road, Bangkok 10400, Thailand
Chavisa Phommalachai
Department of Occupational Health and Safety, Faculty of Public Health, Mahidol University, 420/1 Rajvidhi Road, Bangkok 10400, Thailand
Pajaree Konthonbut
Department of Occupational Health and Safety, Faculty of Public Health, Mahidol University, 420/1 Rajvidhi Road, Bangkok 10400, Thailand
Nattagorn Choochouy
Faculty of Public Health, Thammasat University Lampang Campus, Lampang 52190, Thailand
Preecha Sowanthip
Center of Excellence on Environmental Health and Toxicology, EHT, Bangkok 10400, Thailand
Phanthawee Khangkhun
Bureau of Elderly Health, Department of Health, Ministry of Public Health, Nonthaburi 11000, Thailand
Jutharak Yimsabai
Department of Medical Technology and Clinical Pathology, Buddhachinaraj Phitsanulok Hospital, 90 Sithamma Traipidok Road, Muang, Phitsanulok 65000, Thailand
Susan Woskie
Department of Public Health, University of Massachusetts Lowell, One University Ave, Lowell, MA 01854-2867, USA
The objective of this study was to investigate the relationship of acute pesticide exposures and acute changes in thyroid hormones among Thai farmers. We recruited 78 farmers, who were scheduled to spray insecticides (chlorpyrifos and/or cypermethrin) or herbicides (paraquat and/or glyphosate). On the day before spraying, farmers collected their first morning void urine and went for blood collection. On the spray day, urine samples were collected at end of the spraying event and they were interviewed with questionnaires. The next morning, the first morning void urine and blood samples were collected. Blood samples were analyzed for thyroid hormones. Urine samples were analyzed for the metabolites of the pesticide sprayed. The results showed that the thyroid hormones, free triiodothyronine (FT3) and total triiodothyronine (T3) were significantly reduced as urinary chlorpyrifos metabolite increased the day after spraying. Total thyroxine (T4) significantly increased as cypermethrin metabolites increased the day after spraying. T4 significantly increased as urinary glyphosate levels increased; however, FT3 and T3 decreased significantly as urinary paraquat levels increased the day after spraying. These findings suggest that acute exposures to the pesticides chlorpyrifos, cypermethrin, paraquat and glyphosate can produce acute effects on the hypothalamic–pituitary–thyroid (HPT) axis, acutely altering thyroid hormone levels.
