Effects of exposure to polychlorinated biphenyls and organochlorine pesticides on thyroid function during pregnancy.
In this study, the authors' objective was to determine whether serum concentrations of polychlorinated biphenyls (PCBs), hexachlorobenzene, p,p'-dichlorodiphenyl trichloroethane (DDT), o,p'-DDT, and p,p'-dichlorodiphenyl dichloroethylene (DDE) are associated with thyroid function during pregnancy. These compounds, as well as thyroid-stimulating hormone, total thyroxine, and free thyroxine, were measured in serum samples collected between October 1999 and October 2000 from 334 pregnant women living in the Salinas Valley, California. Data were analyzed by multivariate linear regression. After adjustment for covariates, seven of the 19 PCB congeners detected in more than 75% of participants and the sum of those congeners were negatively associated with free thyroxine concentrations. PCBs 44, 52, and 183 remained significant after the exclusion of two outliers. Hexachlorobenzene concentrations were negatively associated with both free thyroxine and total thyroxine. PCB and hexachlorobenzene concentrations were strongly correlated, which hampered the authors' ability to identify their independent associations with thyroid function. None of the exposures under study were associated with thyroid-stimulating hormone. Results suggest that exposure to PCBs and/or hexachlorobenzene at background levels may affect thyroid function during pregnancy. These findings are of particular significance, since thyroid hormones of maternal origin may play an essential role in fetal neurodevelopment.
Center for Children's Environmental Health Research, School of Public Health, University of California, Berkeley, Berkeley, CA 94704-7380, USA.
Jonathan
J
Chevrier
Brenda
B
Eskenazi
Nina
N
Holland
Asa
A
Bradman
Dana B
DB
Barr
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D003633:Dichlorodiphenyl Dichloroethylene / Q000009:adverse effects / Q000097:blood; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D006581:Hexachlorobenzene / Q000009:adverse effects / Q000097:blood; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000009:adverse effects* / Q000097:blood; D007306:Insecticides / Q000009:adverse effects / Q000097:blood; D018811:Maternal Exposure / Q000009:adverse effects*; D017058:Mexican Americans; D010575:Pesticides / Q000009:adverse effects / Q000097:blood; D011078:Polychlorinated Biphenyls / Q000009:adverse effects* / Q000097:blood; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood / Q000453:epidemiology; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000187:drug effects* / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood* / Q000187:drug effects; D013974:Thyroxine / Q000097:blood* / Q000187:drug effects
D015415:Biomarkers; D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D010575:Pesticides; D003633:Dichlorodiphenyl Dichloroethylene; D006581:Hexachlorobenzene; D013972:Thyrotropin; D011078:Polychlorinated Biphenyls; D013974:Thyroxine