Urinary Iodine Concentration and Thyroid Volume in Schoolchildren of Sofia: Evaluation of Effectiveness of Salt Iodization

Ludmila B. Ivanova1, Ralitza B. Ivanova2, Plamen S. Dimitrov1, Rusana D. Kovatcheva2, and Boyan S. Lozanov2

1 Medical Ecology and Nutrition, National Centre of Hygiene, Sofia, Bulgaria
2 University Hospital of Endocrinology “Academic Ivan Penchev”, Sofia, Bulgaria

Corresponding author: Assoc. Prof. Ludmila Ivanova, M.D. Ph.D.
    Medical Ecology and Nutrition
    National Center of Hygiene
    15 Dimitar Nestorov St.
    1431 Sofia, Bulgaria
    Telephone: + 359 2 5812529
    Fax number: + 359 2 9581277
    E-mail address: l.ivanova@nchmen.government.bg


Key words:
Iodine deficiency, ioduria, thyroid volume, iodine supplementation, salt iodization

CEJOEM 2002, Vol.8. No.4.: 263–269


Abstract:
The study aimed to evaluate the impact of salt iodization on iodine intake and its effect on the thyroid gland volume of schoolchildren in Sofia City. An epidemiological cross-sectional cluster survey on a total number of 313 schoolchildren of either sex, aged 7–11 years, was conducted. Determination of iodine excretion and thyroid volume by ultrasonography was used to evaluate the iodine status of the study group. The amount of excreted iodine was evaluated according to the of ICCIDD/UNICEF/WHO epidemiological criteria. The thyroid volume was compared to the WHO-recommended upper normal limit for thyroid volume of children aged 6–15 years as a function of age. The median iodine excretion of all groups by age and sex was above 100 mg/L, which is the lower cut-off value for normal excretion in iodine-sufficient population. Only 23.3% of the total number of subjects did not exceed the values of 100 m g/L and 1% was below 20 m g/L. The prevalence of children with excessive iodine excretion (above 300 m g/L) was only 6.6%. Median thyroid volume above the 97 percentile was observed in 2.2% of all cases. Above P97 was the median thyroid volume of the group of 8-year old children of either sex, as well as boys aged 10 and girls aged 11. The iodine prophylaxis in Sofia City is adequate, which is supported by optimal nutritional iodine in schoolchildren.


Received:  22 January 2003
Accepted:  4 March 2003

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