title: Interaction between organophosphate pesticide exposure and PON1 activity on thyroid function.
abstract: Organophosphate pesticides are widely used in agricultural purposes. Recently, a few studies have demonstrated the ability of these chemicals to alter the function of the thyroid gland in human. Moreover, the paraoxonase-1 enzyme (PON1) plays an important role in the toxicity of some organophosphate pesticides, with low PON1 activity being associated with higher pesticide sensitivity. This study evaluates the interaction between exposure to organophosphate compounds and PON1 enzyme activity on serum levels of TSH and thyroid hormones in a population of workers occupationally exposed to pesticides. A longitudinal study was conducted on a population of floriculture workers from Mexico, during two periods of high and low-intensity levels of pesticide application. A structured questionnaire was completed by workers containing questions on sociodemographic characteristics and other variables of interest. Urine and blood samples were taken, and biomarkers of exposure (dialkylphosphates), susceptibility (PON1 polymorphisms and activity) and effect (thyroid hormone levels) were determined. Interaction between dialkylphosphates and PON1 polymorphisms or PON1 activity on hormone levels was evaluated by generalized estimating equation (GEE) models. A significant interaction was found between serum diazoxonase activity and total dialkylphosphates (ΣDAP) on TSH levels. Thus, when PON1 activity was increased we observed a decrease in the percentage of variation of TSH level for each increment in one logarithmic unit of the ΣDAP levels. This interaction was also observed with the PON1(192)RR genotype. These results suggest a stronger association between organophosphate pesticides and thyroid function in individuals with lower PON1 activity.
authors.affiliation: Escuela Andaluza de Salud Pública, Granada, Spain. marina.lacasana.easp@juntadeandalucia.es
authors.forename: Marina
authors.initials: M
authors.lastname: Lacasaña
authors.forename: Inmaculada
authors.initials: I
authors.lastname: López-Flores
authors.forename: Miguel
authors.initials: M
authors.lastname: Rodríguez-Barranco
authors.forename: Clemente
authors.initials: C
authors.lastname: Aguilar-Garduño
authors.forename: Julia
authors.initials: J
authors.lastname: Blanco-Muñoz
authors.forename: Oscar
authors.initials: O
authors.lastname: Pérez-Méndez
authors.forename: Ricardo
authors.initials: R
authors.lastname: Gamboa
authors.forename: Beatriz
authors.initials: B
authors.lastname: Gonzalez-Alzaga
authors.forename: Susana
authors.initials: S
authors.lastname: Bassol
authors.forename: Mariano E
authors.initials: ME
authors.lastname: Cebrian
mesh_terms: D000328:Adult; D000383:Agriculture; D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008800:Mexico / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects; D009943:Organophosphorus Compounds / Q000097:blood / Q000378:metabolism* / Q000652:urine; D010575:Pesticides / Q000097:blood / Q000378:metabolism* / Q000652:urine; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000201:enzymology / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood / Q000652:urine; D055815:Young Adult
chemical_list: D015415:Biomarkers; D009943:Organophosphorus Compounds; D010575:Pesticides; D013972:Thyrotropin; D043303:Aryldialkylphosphatase