Epidemiology and Pathophysiology of Benign Thyroid Disease

Epidemiology Goiter: In iodine-deficient areas, goiter prevalence may be as high as 80%. After correction of iodine deficiency, prevalence decreases slowly over a generation’s time to but not below a few per cent. In iodine-sufficient areas, cross-sectional studies showed a decline in frequency of diffuse goiter and, in contrast, an increase of thyroid nodules and thyroid antibodies with age. For prevalence of diffuse goiter, the ratio of women to men is at least 4:1. Hyperthyroidism: In iodine-sufficient areas, Graves’ disease is the most frequent cause of hyperthyroidism and accounts for about 70% of the cases. Its prevalence may be as high as 1%. In areas with actual or recent iodine deficiency, Plummer’s disease is more frequent due to a much higher prevalence of nodular goiter. Prevalence and incidence of thyrotoxicosis is higher in females than in males by a factor of 5 to 10.