Thyroid Hormones in Conventional and Organic Farmers in Thailand

Pornpimol Kongtip, Noppanun Nankongnab, Nichcha Kallayanatham, Ritthirong Pundee, Nattagorn Choochouy, Jutharak Yimsabai and Susan Woskie
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Pornpimol Kongtip: Department of Occupational Health and Safety, Faculty of Public Health, Mahidol University, 420/1 Rajvidhi Road, Bangkok 10400, Thailand
Noppanun Nankongnab: Mahidol University, Nakhonsawan Campus, Nakhon Sawan 60000, Thailand
Nichcha Kallayanatham: Department of Occupational Health and Safety, Faculty of Public Health, Mahidol University, 420/1 Rajvidhi Road, Bangkok 10400, Thailand
Ritthirong Pundee: Mahidol University, Nakhonsawan Campus, Nakhon Sawan 60000, Thailand
Nattagorn Choochouy: Faculty of Public Health, Thammasat University Lampang Campus, Lampang 52190, Thailand
Jutharak Yimsabai: Buddhachinaraj Phitsanulok, 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

IJERPH, 2019, vol. 16, issue 15, 1-13

Abstract: Pesticides can act as endocrine disruptors by different mechanisms including inhibition of iodine absorption, increases in thyroid hormone clearance, decreased cellular uptake of thyroid hormones, or changes in expression of thyroid hormone regulated genes. This study examined how exposure to pesticides impacts thyroid hormone levels, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4) by comparing conventional ( n = 195) and organic farmers ( n = 222), and by evaluating which types of pesticides might be associated with changes in thyroid hormone levels. Questionnaires were used to collect information about farmer characteristics, self-reported stress, agricultural activities, and history of pesticide use. Conventional farmers were asked to report the type and quantity of pesticides used each day. The TSH, FT3, T3, and T4 levels of conventional farmers were 1.6, 1.2, 1.3, and 1.1 times higher than those of organic farmers, respectively, after adjusting for covariates. Several specific herbicides had a significant relationship between the amount applied and an increase in thyroid hormone levels, after covariate adjustment. They included: paraquat (TSH, FT3 and T3); acetochlor (FT4); atrazine (TSH, FT3 and T3); glyphosate (T4); diuron (TSH) and the “other” herbicides including alachlor, propanil, and butachlor (FT4 and T3). The most commonly used herbicide among conventional farmers was glyphosate, followed by paraquat, 2,4-dichlorophenoxyacetic acid (2,4-D). These findings suggest that exposure to pesticides could impact the development of metabolic diseases and other health outcomes by altering the endocrine system (the thyroid hormone levels) through the hypothalamic–pituitary–thyroid (HPT) axis. This work is a part of a longitudinal study which will evaluate the sub-chronic effects of repeated exposure to different types of pesticides on thyroid hormone levels.

Keywords: conventional farmers; organic farmers; pesticides; thyroid hormone (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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