Thyroid Disorders in Central Ghana: The Influence of 20 Years of Iodization.

Abstract

Background: Ghana began mandatory iodization of salt in 1996. This study compares the prevalence of thyroid disorders before and after the introduction of iodization.

Methods: This is a retrospective study of thyroid cases from the middle belt of Ghana between 1982 and 2014. To demonstrate a link between iodization and hyperthyroidism and autoimmunity, we compared the prevalence of hyperthyroidism and autoimmune thyroid disorders before and after the iodization programme.

Results: A total of 10,484 (7548 females, 2936 males) cases were recorded. The rate of thyroid cases seen was 343/100,000. Nontoxic nodular goiters (25.7%) and toxic nodular goiters (22.5%) represented the second commonest thyroid disorders recorded. The prevalence of hyperthyroid disorders seen after 1996 was significantly higher than the prevalence seen before the iodization (40.0 versus 21.1%, p < 0.001). The prevalence of autoimmune disorders recorded after iodization was significantly higher than that before the iodization programme started (22.3% versus 9.6%, p < 0.001).

Conclusions: This study has revealed a significant increase in thyroid admissions in Central Ghana over the decades. A connection between iodine fortification and iodine-induced hyperthyroidism and between iodine fortification and autoimmune thyroiditis has been shown in this study.