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.