Differences in aetiology and thyroid function in endemic goitre between rural and urban areas of the Darfur region of the Sudan.

To investigate further the possible causes of the difference in goitre frequency between the rural and urban areas of Darfur region in the Sudan, urinary iodine excretion (UIE) and thyroid hormone concentrations were measured in 97 goitrous and 31 non-goitrous subjects from rural Darfur, 62 goitrous subjects from urban Darfur and 37 non-goitrous subjects from Khartoum. The mean UIE was equally low in goitrous subjects from rural Darfur (56.2 +/- 43.1 micrograms/g creatinine) and urban Darfur (46.3 +/- 20.7 micrograms/g creatinine) and both values were lower than that in the non-goitrous subjects from Khartoum (83.6 +/- 41.9 micrograms/g creatinine). Subjects from rural Darfur also had lower mean serum thyroxine and higher triiodothyronine and thyroid stimulating hormone levels. The mean serum thiocyanate level of 3.2 mg/l in goitrous subjects from rural Darfur was significantly higher than the values of 1.8 ng/ml in goitrous subjects from urban Darfur (P less than 0.001) and 1.7 mg/l in non-goitrous subjects from Khartoum (P less than 0.001). It is concluded that the additional contribution of goitrogenic factors in rural Darfur induces thyroid anomalies to a greater degree than are most likely caused by the iodine deficiency alone in subjects from urban Darfur.