Peter N Taylor1, Onyebuchi E Okosieme, Rhian Murphy, Charlotte Hales, Elisabetta Chiusano, Aldo Maina, Mohamed Joomun, Jonathan P Bestwick, Peter Smyth, Ruth Paradice, Sue Channon, Lewis E Braverman, Colin M Dayan, John H Lazarus, Elizabeth N Pearce. 1. Thyroid Research Group (P.N.T., O.E.O., C.H., C.M.D., J.H.L.), Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff, United Kingdom CF14 4XN; Department of Paediatric Psychology (R.M., R.P., S.C.), St. David's Children's Centre, Cardiff, United Kingdom CF11 9XB; Città della Salute e della Scienza - Ospedale Sant'Anna (E.C., A.M.,), Turin, Italy 10100; Wolfson Institute of Preventive Medicine (M.J., J.P.B.), Barts and the London School of Medicine and Dentistry, London, United Kingdom B15 2TT; University College Dublin School of Medicine (P.S.), University College, Dublin, Ireland, Dublin 4; and Section of Endocrinology, Diabetes, and Nutrition (L.E.B., E.N.P.), Boston University School of Medicine, Boston, Massachusetts.
Abstract
OBJECTIVE: Thyroid dysfunction is associated with impaired cognitive development. Perchlorate decreases thyroidal iodine uptake, potentially reducing thyroid hormone production. It is unclear whether perchlorate exposure in early life affects neurodevelopment. DESIGN: Historical cohort analysis. PATIENTS: From 2002 to 2006, 21,846 women at gestational age <16 weeks recruited from antenatal clinics in Cardiff, UK and Turin, Italy were enrolled in the Controlled Antenatal Thyroid Screening Study (CATS). We undertook a retrospective analysis of 487 mother-child pairs in mothers who were hypothyroid/hypothyroxinemic during pregnancy and analyzed whether first trimester maternal perchlorate levels in the highest 10% of the study population were associated with increased odds of offspring IQ being in the lowest 10% at 3 years of age. MAIN OUTCOME MEASURES: Maternal urinary perchlorate, offspring IQ. RESULTS: Urine perchlorate was detectable in all women (median 2.58 μg/L); iodine levels were low (median 72 μg/L). Maternal perchlorate levels in the highest 10% of the population increased the odds of offspring IQ being in the lowest 10% OR = 3.14 (95% CI 1.38, 7.13) P = .006 with a greater negative impact observed on verbal OR = 3.14 (95% CI 1.42, 6.90) P = .005 than performance IQ. Maternal levothyroxine therapy did not reduce the negative impact of perchlorate on offspring IQ. CONCLUSIONS: This is the first study using individual-level patient data to study maternal perchlorate exposure and offspring neurodevelopment and suggests that high-end maternal perchlorate levels in hypothyroid/hypothyroxinemic pregnant women have an adverse effect on offspring cognitive development, not affected by maternal levothyroxine therapy. These results require replication in additional studies, including in the euthyroid population.
OBJECTIVE: Thyroid dysfunction is associated with impaired cognitive development. Perchlorate decreases thyroidal iodine uptake, potentially reducing thyroid hormone production. It is unclear whether perchlorate exposure in early life affects neurodevelopment. DESIGN: Historical cohort analysis. PATIENTS: From 2002 to 2006, 21,846 women at gestational age <16 weeks recruited from antenatal clinics in Cardiff, UK and Turin, Italy were enrolled in the Controlled Antenatal Thyroid Screening Study (CATS). We undertook a retrospective analysis of 487 mother-child pairs in mothers who were hypothyroid/hypothyroxinemic during pregnancy and analyzed whether first trimester maternal perchlorate levels in the highest 10% of the study population were associated with increased odds of offspring IQ being in the lowest 10% at 3 years of age. MAIN OUTCOME MEASURES: Maternal urinary perchlorate, offspring IQ. RESULTS: Urine perchlorate was detectable in all women (median 2.58 μg/L); iodine levels were low (median 72 μg/L). Maternal perchlorate levels in the highest 10% of the population increased the odds of offspring IQ being in the lowest 10% OR = 3.14 (95% CI 1.38, 7.13) P = .006 with a greater negative impact observed on verbal OR = 3.14 (95% CI 1.42, 6.90) P = .005 than performance IQ. Maternal levothyroxine therapy did not reduce the negative impact of perchlorate on offspring IQ. CONCLUSIONS: This is the first study using individual-level patient data to study maternal perchlorate exposure and offspring neurodevelopment and suggests that high-end maternal perchlorate levels in hypothyroid/hypothyroxinemic pregnant women have an adverse effect on offspring cognitive development, not affected by maternal levothyroxine therapy. These results require replication in additional studies, including in the euthyroid population.
Authors: S Hüser; S Guth; H G Joost; S T Soukup; J Köhrle; L Kreienbrock; P Diel; D W Lachenmeier; G Eisenbrand; G Vollmer; U Nöthlings; D Marko; A Mally; T Grune; L Lehmann; P Steinberg; S E Kulling Journal: Arch Toxicol Date: 2018-08-21 Impact factor: 5.153
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