Determination of iodine concentration in urine by isotope dilution analysis and thyroid volume of school children in the west coast of Turkey after mandatory salt iodization.

OBJECTIVE: This study was designed to evaluate iodine deficiency status in children 6-12 years in the west coast (Aegean Region) of Turkey after 5 years of mandatory iodine prophylaxis. A total of 2300 children from 72 populations (rural and urban area) were evaluated with urinary iodine excretion and thyroid volume.
DESIGN: Cross-sectional, observational study designed and performed according to surveillance methods for iodine deficiency disease (IDD) prevalence recommended by WHO/UNICEF/ICCIDD.
SUBJECTS: The study population consisted of 2300 school children age ranging from 6 to 12 years. The children were selected by multiple stage randomization from 91 primary schools of 76 zones (91 clusters). Information about the use of iodized salt was obtained from the families. MEASUREMENTS: Data on the following were collected: birth date, sex, weight, height, thyroid size by palpation and ultrasonography; and urinary iodine by isotope dilution analysis method. Thyroid volumes above 97th percentile according to the WHO/ICCIDD by age and body surface area (BSA) were accepted as goitre.
RESULTS: Iodized salt consumption was 51.7%. The prevalence of goitre determined by palpation was 12.1% and by ultrasound based on BSA and age were 9.8% and 5.5%, respectively. Median urinary iodine was 53 (2-142) microg/l.
CONCLUSION: Mild to severe degree of iodine deficiency was detected in the west coast of Turkey.