title: Organochlorine compounds, iodine intake, and thyroid hormone levels during pregnancy.
abstract: The effect of organochlorine compounds (OCs) on thyroid function, as well as the potential confounding effect of iodine intake, was studied in a large sample of pregnant women from two population-based cohort studies in Sabadell (n = 520) and Gipuzkoa (n = 570), Spain. Thyroid hormones (free T4 and total T3), thyrotropin, and polychlorinated biphenyls (PCB congeners 118, 138, 153, and 180), hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), dichlorodiphenyl dichloroethylene (p'p'-DDE) and dichlorodiphenyl richloroethane (p'p-DDT) were measured in serum samples collected at first trimester of pregnancy. Urinary iodine concentration (UIC) was measured and iodine intake from diet, iodized salt, and supplements were estimated from a food frequency questionnaire. Levels of HCB and PCBs congeners 180, 153, and 138 were related to lowe rtotal T3 levels (adjusted coefficient (SE): -4.0(1.1), -6.1(1.6), -5.5(1.6), and 3.8(1.4), respectively) and higher free T4 levels (adjusted coefficient (SE): 0.013(0.05), 0.017(0.007), 0.016(0.007), and 0.007(0.006), respectively). These associations were homogeneous in both cohorts, especially for PCBs and total T3 (p-value forthe interaction between cohorts >0.8). Iodine intake and UIC did not affect the association between OCs and thyroid hormones. Our results indicate that exposure to OCs during pregnancy can alter TH levels.
authors.affiliation: Centre for Research in Environmental Epidemiology, Barcelona, Spain. malvarez@creal.cat
authors.forename: Mar
authors.initials: M
authors.lastname: Alvarez-Pedrerol
authors.forename: Monica
authors.initials: M
authors.lastname: Guxens
authors.forename: Jesús
authors.initials: J
authors.lastname: Ibarluzea
authors.forename: Marisa
authors.initials: M
authors.lastname: Rebagliato
authors.forename: Agueda
authors.initials: A
authors.lastname: Rodriguez
authors.forename: Mercedes
authors.initials: M
authors.lastname: Espada
authors.forename: Fernando
authors.initials: F
authors.lastname: Goñi
authors.forename: Mikel
authors.initials: M
authors.lastname: Basterrechea
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
mesh_terms: D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000009:adverse effects*; D007455:Iodine / Q000008:administration & dosage*; D011247:Pregnancy / Q000097:blood*; D013972:Thyrotropin / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D006843:Hydrocarbons, Chlorinated; D014284:Triiodothyronine; D013972:Thyrotropin; D007455:Iodine