title: Neurotoxicant exposure during pregnancy is a confounder for assessment of iodine supplementation on neurodevelopment outcome.
abstract: BACKGROUND
  The developing brain is vulnerable to iodine deficiency (ID) and environmental neuro-toxicants.
  
  
  OBJECTIVE
  To assess neurocognitive development of children whose mothers have received (or not) iodine supplementation during pregnancy, in an area of borderline ID, while assessing in utero exposure to environmental neuro-toxicants.
  
  
  METHODS
  Among 86 children born from normal euthyroid women who participated in our prospective interventional study on iodine supplementation (150 μg/day) started early in pregnancy, 44 (19 with iodine supplementation, 25 controls) were assessed at two years using the Bayley test. Information on parents' education and habits (smoking), and on child development was recorded. Thyroid tests at each trimester of pregnancy and on cord blood (CB) were available, as well as milk concentrations of selected environmental compounds known for their neurotoxicity, including heavy metals and PCBs.
  
  
  RESULTS
  There was no difference in Bayley tests for children born to mothers with and without iodine supplementation, but sample size was small. Language and Social-Emotional Scales were negatively correlated with TBG at all times tested, while PCB 118 correlated negatively with all Language scales. Among maternal and CB thyroid tests, only CB thyroglobulin, the best marker of iodine status, correlated (negatively) with neurodevelopment scales (Motor and Expressive Language).
  
  
  CONCLUSIONS
  This pilot study suggests that PCB118 has a negative impact on neurocognitive development, possibly mitigating the benefit of iodine supplementation in an area of borderline ID. We propose that exposure to environmental neurotoxicants should be taken into account when designing studies on the benefit of iodine supplementation in pregnancy. The potential interactions between TBG, environmental neurotoxicants and brain development warrant further studies.
authors.affiliation: Department of Endocrinology, Diabetology and Reproductive Medicine, CHU de Nice, Nice, France; Institut National de la Recherche Médicale, UMR U895, Université Nice-Sophia Antipolis, Nice, France. Electronic address: brucker-davis.f@chu-nice.fr.
authors.forename: Françoise
authors.initials: F
authors.lastname: Brucker-Davis
authors.affiliation: Department of Neurology, Centre d'Action Médico-Sociale Précoce (CAMPS), CHU-Lenval, Nice, France.
authors.forename: Fleur
authors.initials: F
authors.lastname: Ganier-Chauliac
authors.affiliation: Departments of Clinical Research and Innovation and Statistics, Epidemiology and Biostatistics Unit, Centre Antoine Lacassagne, Nice, France.
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Gal
authors.affiliation: Department of Biochemistry, CHU de Nice, Nice, France.
authors.forename: Patricia
authors.initials: P
authors.lastname: Panaïa-Ferrari
authors.affiliation: Observatoire du Développement Durable, Métropole Nice-Côte d'Azur, Nice, France.
authors.forename: Patricia
authors.initials: P
authors.lastname: Pacini
authors.affiliation: Department of Endocrinology, Diabetology and Reproductive Medicine, CHU de Nice, Nice, France; Institut National de la Recherche Médicale, UMR U895, Université Nice-Sophia Antipolis, Nice, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Fénichel
authors.affiliation: Department of Endocrinology, Diabetology and Reproductive Medicine, CHU de Nice, Nice, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Hiéronimus
mesh_terms: D000328:Adult; D000891:Anti-Infective Agents, Local / Q000097:blood / Q000633:toxicity*; D015331:Cohort Studies; D002658:Developmental Disabilities / Q000175:diagnosis / Q000209:etiology*; D019587:Dietary Supplements / Q000633:toxicity*; D005260:Female; D006801:Humans; D007455:Iodine / Q000097:blood / Q000633:toxicity*; D008297:Male; D009483:Neuropsychological Tests; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000209:etiology / Q000503:physiopathology*; D013223:Statistics as Topic; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D055815:Young Adult
chemical_list: D000891:Anti-Infective Agents, Local; D014284:Triiodothyronine; D013972:Thyrotropin; D007455:Iodine; D013974:Thyroxine
keywords: Heavy metals; Iodine; Neuro-cognitive development; PCB 118; Pregnancy; Thyroid tests; Thyroxine-Binding-Globulin