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Introduction: Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants found in human tissues. PCBs can be transferred through the placenta and may disrupt the thyroid system. Several studies have shown that intrauterine exposure to PCBs might be associated with abnormal thyroid function.
Objective: To examine the correlation between intrauterine exposure to PCBs and thyroid hormones levels in an Israeli cohort.
Methods: The EHF-Assaf Harofeh Ichilov (EHF-AHI) includes 174 mothers-newborns dyads. PCBs levels, serum lipids and thyroid functions in mothers` serum. T4 levels were measured in blood drawn from heel prick of newborns as part of the national survey.
Results: Maternal median age was 31 (19-44) years. Median birth week was 39 (34-41). Median birth weight was 3147.5 (1442.3-4720) gr. Four PCBs types were analyzed: PCBs 118, 138, 153 and 180 median levels were 2.43 (0.73-15.7), 3.56 (1.06-29.08), 5.77 (1.65-54.5) and 4.2 (0.85-32.5) ng/g lipids, respectively. Maternal median FT4 and TSH levels were 12.4 (7.58-19.83, normal range 12-22) µg/dl and 2.66 (0.14-7.5, normal range 0.27-4.2) µIU/ml, respectively. Newborns median T4 levels was 14.7 (7.6-24.9, normal range 6.2-22.0) µg/dL.
No correlation between each of the PCB congeners or total PCBs and thyroid levels was found.
Conclusion: compared to other studies, we found low PCBs levels, which suggests low exposure of this population to PCBs. The lack of correlation between PCBs levels in the mother and thyroid function in the newborn, may be explained by the low levels of PCBs that which probably do not affect the thyroid system at these levels.
