The Onset of Iodine-induced Hyperthyroidism Among Women of Child Bearing Age in Ekiti East and Ekiti West Local Government Areas of Nigeria Following the Mandatory Salt Iodization Programme


  • D. D. Ajayi, A. O. Awoyinka and O. B. Ajayi


Iodine-induced hyperthyroidism, Table salt, Urinary iodide, Protein deficiency


One of the adverse outcomes of most iodine supplementation programs is iodine-induced hyperthyroidism. Following the baseline nationwide survey conducted in 1993 which revealed the high prevalence of iodine deficiency in Nigeria, a universal salt iodization strategy was implemented. The purpose of this study was to determine the prevalence of iodine-induced hyperthyroidism in some previously iodine-deficient villages in Ekiti. Altogether, 97 women from an Ogun State control community with no iodine deficiency as per previous studies and 592 women of childbearing age from 10 distinct Ekiti state villages took part in the study. The respondents had samples of their blood, urine, and salt obtained for routine analytical procedures. The prevalence of iodine-induced hyperthyroidism was 1.21% in Ekiti East and 0.59% in Ekiti West local government areas. Urinary iodide concentrations were 26.16 ± 8.39 μg/dl, 26.52±9.68 μg/dl, 24.34±9.53 μg/dl and were significantly higher in Iworo, Iludofin and Aramoko communities compared with 22.15±6.68 μg/dl in the control. Between 10 and 50% of the salt samples in the test and control areas had salt iodine concentrations over the WHO threshold of 20–40 ppm.  Comparing the iodine-induced hyperthyroid respondents with the controls, the TSH and albumin values were significantly lower (P<0.05), whereas the T3, T4, and urine iodide values were significantly higher (P<0.05). The study showed that iodine-induced hyperthyroidism incidence in some Ekiti communities is high. Advocacy, the implementation of a quantitative technique of salt evaluation at the community level, and proper monitoring of salt iodization at the factory level are suggested as remedies.

Author Biography

D. D. Ajayi, A. O. Awoyinka and O. B. Ajayi