2678

Background: Metals may disrupt thyroid hormones (TH) like thyroid stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3). We examined whether hair (MnH) and blood manganese (MnB), and blood lead (PbB) concentrations explained serum TH concentrations in pregnant women from the ISA birth cohort in Costa Rica.Methods: Using the first sample of each women (n=384), we ran separate multivariate linear regression models and General Additive Models (GAMs) adjusting for gestational age, maternal age, cotinine, prepregnancy Body Mass Index and severe vomiting. We also ran stratified analysis by trimester of pregnancy.Results: Median (p25-75) TSH, FT3, FT4 concentrations were: 1.47 (1.06-2.08) mIU/L, 4.60 (4.29-5.06) pmol/L, and 14.09 (13.00-15.65) pmol/L, respectively. Median (p25-75) MnH, MnB and PnB were 1.62 (0.86-3.49) μg/g, 23.44 (19.36-27.43), 6.66 (5.17-9.08) μg/L, respectively. Increased MnH was associated with increased TSH (% of change = 13,24, 95%CI -1,95, 30,79 for each 1% increase in MnH) during the second trimester of pregnancy. In addition, MnH showed a non-linear association with FT4 during the third trimester of pregnancy (GAM estimated degrees of freedom >2 with p<0.05).  Overall, higher MnB concentrations were associated with increased FT4, ß=0,04 (95%CI 0, 0,07). Associations were strongest during the first trimester ß=0,13 95% CI: 0,05, 0,21). MnB also showed a non-linear association with FT3 during the first trimester.  Finally, increased PbB concentrations were associated with higher FT4 [β=0.07 (95% CI: 0.00, 0.13)], particularly during the second trimester of pregnancy [β=0.10 (95% CI: 0.02, 0.19)]Conclusion: Our findings show that both manganese and lead explain TH concentrations during pregnancy. For Mn, being an essential element, this may reflect normal physiological functioning. Nevertheless, increased MnH is likely to reflect excess Mn and associations may also reflect endocrine disrupting effects. For lead, results show even very low concentrations might affect TH and possibly cause endocrine disrupting effects. 

2551

Background: Fungicides and insecticides are extensively used in Costa Rican agriculture and evidence suggests that early-life exposure may impair children's neurodevelopment. We examined whether prenatal and current insecticide and fungicide exposure was associated with neurodevelopmental outcomes in preschoolers from the Infants′ Environmental Health Study (ISA).
Methods: We measured pesticide metabolite concentrations in maternal and children’s urine collected 1-3 times during pregnancy and 1-3 times when children aged 5-6 years. We measured hydroxy-tebuconazole (TEB-OH) and 3,5,6-trichloro-2-pyridinol (TCPy) to evaluate exposure to tebuconazole and chlorpyrifos respectively. We administered the Child Behavior Checklist (CBCL) to the mothers (mean child age=5.7 ± 0.4 years) (n=292). We assessed attention using the Conners K-CPT 2™ and executive-function using the Dimensional Change Card Sorting test (DCCS). We ran separate linear regression models for log-10 transformed prenatal and current metabolite concentrations with CBCL or Conners scores and logistic regression models for DCCS scores, adjusting for relevant covariables. We also examined effect-modification by sex.
Results: Median (p25-p25) specific gravity-adjusted urinary prenatal and current TCPy were: 1.75 (1.31-2.53) and 1.67 (1.17-2.32) µg/L. Current median concentration of TEB-OH were 0.24 (0.14-0.40) µg/L. Higher current TEB-OH concentrations were associated with worse CBCL scores (total scale, ß=3.29, 95%CI= 0.26, 6.32, per ten-fold increase in exposure) and particularly among girls (ß=6.39, 95%CI 2.17-10.6, per ten-fold increase in exposure). Higher prenatal TCPy concentrations were associated with worse CBCL scores for the internalizing scale in girls (ß=5.92, 95%CI= 0.65, 11.2, per ten-fold increase in exposure) but also with decreased hit-time (Conners test) (ß=-3.12, 95%CI= -6.07, -0.18, per ten-fold increase in exposure) and worse executive-function scores (DCCS: OR =0.02, 95%CI= 0.00, 0.28) in the entire sample.
Conclusion: Results suggest current fungicide exposure negatively affects young children’s behavior; effects may be stronger for girls. Also, prenatal exposure to chlorpyrifos may negatively affect children's behavior, attention and executive-function.