Environmental contamination with metals as a risk factor causing developing autoimmune thyroiditis in children in zones influenced by emissions from metallurgic enterprises

Chemical environmental factors trophic for the endocrine system and its organs produce negative influence on it that becomes apparent through growing incidence and pathomorphism of endocrine diseases. Our test group was made up of 102 children with diagnosed autoimmune thyroiditis (AIT) who were chronically exposed to metals (lead, manganese, nickel, chromium, and zinc) being components in emissions from metallurgic enterprises in Perm region. Our reference group included 46 children with AIT who lived beyond zones influenced by the aforementioned enterprises in areas with the sanitary-hygienic situation being relatively favorable. We comparatively analyzed the results of clinical and ultrasound examinations that focused on evaluating children’s thyroidal and immune state. A growth in incidence with thyroiditis amounted to 63.6 % on the test territory over 10 years and it was 1.6 times higher than on average in the region (40.8 %); there was no growth in the indicator detected on the reference territory. Concentrations of chromium, nickel, lead, zinc, and manganese higher than regional background level were 1.7-5.5 times more frequently detected in blood of children from the test group against the reference one. A number of AIT cases was higher among exposed boys (by 2.0 times, p = 0.070); exposed children also had higher Ig A, M, and G contents in blood serum (by up to 2.9 times, p = 0.015-0.056), higher TSH levels (by 2.0 times, p = 0.096), and lower free T4 contents (by 5.4 times, p = 0.057). Diffuse damage to the thyroid gland was by 1.3 times more frequent under exposure to adverse factors created by metallurgic production; AIT combined with other diseases was also more frequent (p = 0.041). Rates and growth in incidence of thyroid gland diseases and thyroiditis are by 1.3-2.3 times higher among children and teenagers living on territories where metallurgic enterprises are located against the same indicators on territories where sanitary-hygienic situation is relatively favorable. We detected less apparent gender-related differences in AIT frequency, a greater number of improper thyroidal state, elevated risks of diffuse changes in the thyroid gland and activation of humoral immune response that was by 2.2-3.4 times more frequent together with concomitant damage to other systems under elevated contents of metals in blood.