MULTIPLE PESTICIDES EXPOSURE OF GREENHOUSE WORKERS AND THYROID PARAMETERS

Abstract

Objective: The persistence of high prevalence of thyroid pathology (goiter, nodules) in Romanian population, despite the correction of iodine deficiency, determined us to evaluate the impact of factors different than iodine intake on the thyroid gland as environmental endocrine disruptors. We studied the potential correlation between pesticide exposure and parameters of the function, autoimmunity and morphology of the thyroid in a group of greenhouse workers (GHWs) exposed to multiple uncontrolled pesticides across agricultural seasons. Materials and methods: A group of 108 GHWs, 18–78 year olds, with normal iodine intake, from a plain village, exposed to multiple pesticides was enrolled voluntary in this study. Thyroid echography, thyroid parameters [thyroid stimulating hormone (TSH), free T4 (FT4), and antibody to thyroid peroxidase (ATPO)], some of the used pesticides (chlorpyrifos, trichloropyridinol (TCP), carbofurane, cypermethrin, dimethoate) and cholinesterase activity were determined in biological samples (urine, blood) collected across two agricultural seasons. Results: The median urinary iodine concentration in children from this village was 135.20 μg/L, while median TSH and median FT4 was 1.72 μUI/mL and 16.68 pmol/L, respectively. Hypothyroidism (TSH > 4.2 μUI/mL) was present in 12.4% of patients, median TSH value was 7.26 μUI/mL. In four of them post-thyroidectomy hypothyroidism was present. Elevated titres of anti-TPO antibodies were found in 22 (20.37%). Echographic pattern of thyroiditis was present in 16.49% of the patients, and thyroid nodules were detected by ultrasonography in 38.13%. There were two subjects with Graves’ disease. The detectable level of TCP was bigger in the fi rst season (range 120–190 μg/L) than in the second (range 0.7–1.7 μg/L). The range of seasonal concentration of urinary carbofurane was .004–0.25 μg/mL. Cypermethrin was detected in a small number of subjects (range: 12.5–13.3 μg/g creatinine). Dimethoate was undetectable. Conclusions: The distribution of thyroid disorders in study group living in an area with normal iodine intake did not differ from known epidemiological studies. The most frequently encountered pesticide was chlorpyrifos. Some samples presented several pesticides simultaneously.