[Iodine status and its influence on thyroid structure and function in children and teenagers after the introduction of an iodine prophylaxis programme in the city of Szczecin].
OBJECTIVE
Studies conducted in the early 1990s revealed the spread of iodine deficiency and endemic goitre throughout Poland and contributed to the adoption of statutory table salt iodization in 1997. The present work was undertaken to assess the efficacy of the current model of iodine prophylaxis on the basis of goitre incidence, ioduria, thyreoglobulin serum concentration, and thyroid gland function in a randomly selected group of children residing in the city of Szczecin between 2002 and 2003.


METHODS
Subjects taking vitamin or mineral preparations enriched with iodine were excluded from the study. The study group included 273 children aged 9 to 16 years (140 boys (52%) and 133 girls (48%). Iodine excretion in urine was determined with the catalytic Sandell-Kolthoff reaction. Radioimmunometric and radioimmunological methods were used for the determination of thyreoglobulin (Tg), thyrotropin (TSH), and free thyroxine (FT4) concentrations. Goitre was confirmed in 12 children (4.3%).


RESULTS
In this subgroup, iodine excretion in urine was significantly lower (75.4 +/-35.66 microg/L vs. 86.1 +/- 44.2 microg/L in children without goitre) and thyreoglobulin serum concentration was higher (14.36 +/- 8.9 microg/L and 11.92 +/- 7.49 microg/L, respectively). The differences in TSH and FT4 concentrations were statistically insignificant. Mean iodine concentration in urine was 86.22 +/- 44.97 microg/L in the whole study group. Abnormal ioduria occurred in more than 65% of children. Mean FT4 concentration was 14.58 +/- 4.49 pmol/L and TSH was 2.16 +/- 1.08 microU/mL in the whole group. Mean thyreoglobulin concentration was 11.94 +/- 7.57 microg/L and was increased in 55% of children. There was a significant correlation of thyreoglobulin with FT4 (rs = -0.24) and thyrotropin (rs = 0.21) concentrations. No correlation was found between the concentration of these hormones and ioduria. Similarly, there was no correlation between thyreoglobulin concentration and iodine urinary excretion. This study revealed a partial efficacy of current model of iodine prophylaxis. One important result of the prophylaxis programme is a decrease in the incidence of goitre below endemic level.


CONCLUSIONS
Mean iodine concentrations in urine and thyreoglobulin serum concentrations demonstrate a state of iodine deficiency in Szczecin region. Correlations between thyreoglobulin concentrations, free thyroxine and thyrotropin suggest that Tg is a more useful indicator of iodine balance than ioduria.
Brodowski
Jacek
J
Katedra i Zakład Medycyny Rodzinnej Pomorskiej Akademii Medycznej ul Podgórna 22/23, Szczecin.
D000293:Adolescent; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002648:Child; D005260:Female; D006043:Goiter, Endemic / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D007455:Iodine / Q000627:therapeutic use* / Q000652:urine; D008297:Male; D008403:Mass Screening / Q000379:methods; D011044:Poland / Q000453:epidemiology; D011159:Population Surveillance; D015397:Program Evaluation; D017673:Sodium Chloride, Dietary; D013954:Thyroglobulin / Q000097:blood; D013960:Thyroid Function Tests
D015415:Biomarkers; D017673:Sodium Chloride, Dietary; C034024:iodized salt; D013954:Thyroglobulin; D007455:Iodine