TY - JOUR
T1 - Thyroid hormones and neurobehavioral functions among adolescents chronically exposed to groundwater with geogenic arsenic in Bangladesh
AU - Khan, Khalid M.
AU - Parvez, Faruque
AU - Zoeller, R. Thomas
AU - Hocevar, Barbara A.
AU - Kamendulis, Lisa M.
AU - Rohlman, Diane
AU - Eunus, Mahbubul
AU - Graziano, Joseph
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/8/15
Y1 - 2019/8/15
N2 - Groundwater, the major source of drinking water in Bengal Delta Plain, is contaminated with geogenic arsenic (As)enrichment affecting millions of people. Children exposed to tubewell water containing As may be associated with thyroid dysfunction, which in turn may impact neurodevelopmental outcomes. However, data to support such relationship is sparse. The purpose of this study was to examine if chronic water As (WAs)from Holocene alluvial aquifers in this region was associated with serum thyroid hormone (TH)and if TH biomarkers were related to neurobehavioral (NB)performance in a group of adolescents. A sample of 32 healthy adolescents were randomly drawn from a child cohort in the Health Effects of Arsenic Longitudinal Study (HEALS)in Araihazar, Bangladesh. Half of these participants were consistently exposed to low WAs (<10 μg/L)and the remaining half had high WAs exposure (≥10 μg/L)since birth. Measurements included serum total triiodothyronine (tT 3 ), free thyroxine (fT 4 ), thyrotropin (TSH)and thyroperoxidase antibodies (TPOAb); concurrent WAs and urinary arsenic (UAs); and adolescents' NB performance. WAs and UAs were positively and significantly correlated with TPOAb but were not correlated with TSH, tT 3 and fT 4 . After accounting for covariates, both WAs and UAs demonstrated positive but non-significant relationships with TSH and TPOAb and negative but non-significant relationships with tT 3 and fT 4 . TPOAb was significantly associated with reduced NB performance indicated by positive associations with latencies in simple reaction time (b = 82.58; p < 0.001)and symbol digit (b = 276.85; p = 0.005)tests. TSH was significantly and negatively associated with match-to-sample correct count (b = −0.95; p = 0.05). Overall, we did not observe significant associations between arsenic exposure and TH biomarkers although the relationships were in the expected directions. We observed TH biomarkers to be related to reduced NB performance as hypothesized. Our study indicated a possible mechanism of As-induced neurotoxicity, which requires further investigations for confirmatory findings.
AB - Groundwater, the major source of drinking water in Bengal Delta Plain, is contaminated with geogenic arsenic (As)enrichment affecting millions of people. Children exposed to tubewell water containing As may be associated with thyroid dysfunction, which in turn may impact neurodevelopmental outcomes. However, data to support such relationship is sparse. The purpose of this study was to examine if chronic water As (WAs)from Holocene alluvial aquifers in this region was associated with serum thyroid hormone (TH)and if TH biomarkers were related to neurobehavioral (NB)performance in a group of adolescents. A sample of 32 healthy adolescents were randomly drawn from a child cohort in the Health Effects of Arsenic Longitudinal Study (HEALS)in Araihazar, Bangladesh. Half of these participants were consistently exposed to low WAs (<10 μg/L)and the remaining half had high WAs exposure (≥10 μg/L)since birth. Measurements included serum total triiodothyronine (tT 3 ), free thyroxine (fT 4 ), thyrotropin (TSH)and thyroperoxidase antibodies (TPOAb); concurrent WAs and urinary arsenic (UAs); and adolescents' NB performance. WAs and UAs were positively and significantly correlated with TPOAb but were not correlated with TSH, tT 3 and fT 4 . After accounting for covariates, both WAs and UAs demonstrated positive but non-significant relationships with TSH and TPOAb and negative but non-significant relationships with tT 3 and fT 4 . TPOAb was significantly associated with reduced NB performance indicated by positive associations with latencies in simple reaction time (b = 82.58; p < 0.001)and symbol digit (b = 276.85; p = 0.005)tests. TSH was significantly and negatively associated with match-to-sample correct count (b = −0.95; p = 0.05). Overall, we did not observe significant associations between arsenic exposure and TH biomarkers although the relationships were in the expected directions. We observed TH biomarkers to be related to reduced NB performance as hypothesized. Our study indicated a possible mechanism of As-induced neurotoxicity, which requires further investigations for confirmatory findings.
KW - Arsenic in aquifer
KW - Drinking water arsenic
KW - Mechanism of neurotoxicity
KW - Thyroid biomarkers
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U2 - 10.1016/j.scitotenv.2019.04.426
DO - 10.1016/j.scitotenv.2019.04.426
M3 - Article
C2 - 31075594
AN - SCOPUS:85065139084
SN - 0048-9697
VL - 678
SP - 278
EP - 287
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -