Thyroid Hormone Levels in Mothers and Cord Blood at Delivery in Crude Oil Producing Community in Delta State, Nigeria

Abstract

Background and objectives: Harm caused by crude oil spillage and its associated environmental toxicants manifests slowly. This study examined the impact of crude oil environmental toxicants on neonates' thyroid and cognitive functions in crude oil-producing communities. Methods:The case-control study comprised 55 crude oil-exposed expectant mothers and 33 non-crude oil-exposed expectant mothers as controls. Serum Benzo Pyrene Dihydrodiol Epoxide (BPDE), triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH) were assayed in expectant mothers and neonates. Intelligence quotient and APGAR scores were determined in the children using Fagan's test of infant intelligence.Results: Serum TSH (p < 0.05) and BPDE (p < 0.001) were higher, while T3 and T3/T4 ratio were significantly lower (p < 0.001) in exposed pregnant women compared to the control. Cord blood TSH and T3/T4 ratio were lower (p < 0.001) while T4 and BDPE were higher (p < 0.001) in prenatally exposed neonates than prenatally non-exposed infants. Serum TSH correlated with BDPE (R 2 = 0.080, p < 0.036) and APGAR score (R 2 = 0.341, p < 0.012), while T3 and T4 were not associated with BDPE and APGAR score. TSH correlated with T3 (R 2 = 0.0.082, p < 0.05), T3 correlated with T4 (R2 = 0.111, p < 0.013) and TSH (R 2 = 0.082, p < 0.05). Exactly 54.5% (30/55) of prenatally exposed neonates had a low intelligence quotient compared to 36.4% (12/33) in prenatally non-exposed neonates. Conclusion:Crude oil and associated environmental pollutants might significantly affect the thyroid function. Environmental surveillance, biomonitoring and environmental cleanup are emphasized. Future research on the mechanisms of the observed toxicological effects on thyroid hormones and targeted protection of pregnant women and their offspring is suggested.