The role of iron deficiency in persistent goiter

Iodine deficiency has been identified as a significant public health problem in Iran. The main strategy for controlling iodine deficiency was nationwide salt iodination. Over 10 years after starting this program, goiter is still endemic in school children. Iron deficiency may have interfered with the iodine intervention program. The objective of the present study was to evaluate the relationships between iron status, thyroid hormone profile, and the prevalence of goiter 11 years after implementation of the salt iodination program.

In this study which was conducted in Marvdasht, Shiraz, 1188 students aged eight to 13 years were enrolled. Goiter was graded according to the classification by the World Health Organization (WHO). Serum concentrations of thyroid hormones and thyroid stimulating hormone were determined using commercial kits. The urinary iodine level was measured using the digestion method.

Goiter was endemic (39.6%); the majority of participants had grade 1 thyromegally. Despite the endemic status of goiter in southern Iran, the urine content of iodine reflected a normal iodine intake. The prevalence of iron deficiency was 16.4%. The iron-deficient patients had a significantly higher thyroid stimulating hormone level and lower free T4 concentrations than those with a normal serum ferritin level (P<0.001).

Iron supplementation may improve thyroid metabolism in children but we still have to investigate the role of other goitrogens in this area.