Endemic goiter with iodine sufficiency: a possible role for the consumption of pearl millet in the etiology of endemic goiter

BACKGROUND: Deficiencies of iodine, iron, and vitamin A are the 3 most common micronutrient deficiencies in developing countries, although control programs, when properly implemented, can be effective. OBJECTIVE: We investigated these deficiencies and their possible interaction in preschool children in the southern Blue Nile area of Sudan. DESIGN: Goiter, signs of vitamin A deficiency, and biochemical markers of thyroid, vitamin A, and iron status were assessed in 984 children aged 1-6 y. RESULTS: The goiter rate was 22. 3%. The median urinary iodine concentration was 0.79 micromol/L and 19.3% of the children had a concentration >1.57 micromol/L. Although serum thyroxine and triiodothyronine concentrations were within reference ranges, the median thyrotropin concentration was 3.78 mIU/L and 44% of the children had thyrotropin concentrations above normal. The mean urinary thiocyanate concentration was high (259 +/- 121 micromol/L). The prevalences of Bitot spots and night blindness were 2.94% and 2.64%, respectively, and 32% of the subjects had serum retinol binding protein concentrations <15 mg/L. A significant positive correlation was observed between thyrotropin and retinol binding protein. Whereas 88% of the children had hemoglobin concentrations <1.86 mmol/L, only 13.5% had serum ferritin concentrations below the cutoff of 12 microg/L and 95% had serum transferrin concentrations above the cutoff of 2.50 g/L. CONCLUSIONS: Our results indicate that goiter is endemic in this region of Sudan despite iodine sufficiency and that both anemia and vitamin A deficiency are health problems in the area. Moreover, consumption of millet, vitamin A deficiency, and protein-energy malnutrition are possible etiologic factors in this endemic area.