Influence of Bisphenol A on Thyroid Volume and Structure Independent of Iodine in School Children

BACKGROUND: Although several studies have evaluated the relationship between bisphenol A (BPA) and thyroid functions, their results are not entirely consistent. Little is known about BPA in relation to thyroid volume and structure. METHODS: We examined the association of BPA with thyroid volume and thyroid nodules using data from 718 Chinese children living in the East Coast of China in 2012. First morning urine samples were collected for the determination of urinary BPA, creatinine, and urinary iodine concentrations (UIC). Thyroid volume (TV) and nodules were assessed by thyroid ultrasonography. RESULTS: The median of TV was 3.14ml. 459(63.9%) children took iodized salt at home and the median of UIC was 159μg/l. BPA was detected in 99.9% of the urine samples and the medians for boys and girls were 2.64 and 2.35μg/g creatinine, respectively. Of all participants 14.0% had thyroid nodules. Urinary BPA concentration was inversely associated with thyroid volume (β = -0.033, 95% CI: -0.053, -0.013) and the risk for multiple nodules (OR = 0.78; 95% CI: 0.63, 0.97). The associations above were similar for children who consumed iodized salt and those consumed non-iodized salt. CONCLUSIONS: The data suggest that BPA may be one of the influencing factors for TV and thyroid nodules and its effects are independent of iodine nutrition status in children.