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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