Is Iron Deficiency Responsible for Endemic Goiter in Semirom?

In spite of iodine fortification programs, goiter is still hyperendemic in Semirom, a mountainous region in the central part of Iran. This study was conducted to assess whether iron deficiency could be responsible for the high prevalence of goiter in this region. A total of 1828 schoolchildren, aged 7-13 years, were evaluated for presence of goiter, and 220 cases were randomly selected. Urine and serum samples were collected from these children and assayed for urinary iodine concentraton (UIC) and serum ferritin, iron, thyroxine (T4) and thyroid stimulating hormone (TSH) concentrations. In the 1828 children evaluated, 670 cases (36.7%) were goitrous, with goiters of grade 1 or 2. The mean UIC in children was 19.3±9.1 µg/dl. Mild (UIC <10 µg/dl) and moderate (UIC <5 µg/dl) iodine deficiency was detected in 6.4% and 3.2% of cases, respectively. Only 1.8% of children were severly iodine deficient (UIC <2 µg/dl). The median serum ferritin concentration was 26.6 ng/ml (95% CI: 24.2-28.9), and 11 cases (5%) had serum ferritin concentrations less than 20 ng/ml. Goiter rate was 48.3% and 50.3% in children with low and normal serum ferritin levels, respectively (P=NS). It seems that factors other than iodine and iron deficiency may, at least partly, be responsible for the high prevalence of goiter in the area studied. Further investigations for evaluating other micronutrient deficiencies and autoimmunity in goitrous children would contribute to the planning more effective goiter control programs.