[Evaluation of influence of selenium, copper, zinc and iron concentrations on thyroid gland size in school children with normal ioduria].

UNLABELLED

Proper diet with regard to quantity and quality of meals is of vital importance for normal development and functioning of the organism. There are many proofs that environmental factors play an important role in the pathogenesis of goiter. Iodine deficit in diet is best known of all factors contributing to goiter. Deficit of other elements like, iron, selenium, copper and zinc is also essential. The purpose of this study was to evaluate the influence of chosen environmental factors, i.e., iron and trace elements of selenium, zinc and copper--essential for the thyroid functioning on the development of goiter in school children aged 6-13 years with normal ioduria in the Polish population.

MATERIAL AND METHODS

In 2002, the study was performed in 4 elementary schools chosen randomly in Białystok and in the Children's Outpatient Clinic of Endocrinology of the Specialist Regional Hospital. The study included 400 children aged 7-13 years from schools and 120 patients at the same age treated with KJ and/or tyroxine for minimum 12 months due to goiter in the Out-patient Clinic of Endocrinology. Basing on the assessment of the thyroid size as well as the criteria of WHO from 1997 year for body surface and sex, children were divided into 2 subgroups: with goiter and the thyroid gland within the norm. Children aged 9-11 years were qualified and chosen from subgroups to further examinations. In both subgroups, blood samples were taken to determine concentrations of iron, selenium, copper and zinc.

RESULTS

The mean concentration of selenium in the blood was statistically significantly lower in children with goiter in comparison with children with the thyroid gland within the norm (44.4 +/- 7.8 microg/L vs. 49.2 +/- 9.1 microg/L, p = 0.044) in the study population of school children and the Outpatient Clinic of Endocrinology. No differences of serum iron concentrations were observed in children with goiter and with the thyroid gland within the norm. However, nearly the half (45.5%) of patients with the lower serum concentration of iron (< 60 microg/dL) had goiter despite average 22-month therapy with KJ and/or tyroxine.

CONCLUSION

Observed, in spite of proper iodine prophylaxis, 7% rate of goiter occurring in school children suggests other than iodine deficiency factors that influence goiter development. The study proved that the low concentration of iron and/or selenium deficit found in the serum of children with goiter in spite of their treatment with KJ and/or tyroxine may be additional factors influencing the effectiveness of this treatment.