Trends in the epidemiology of thyroid diseases in Bulgaria since the year 2000-a review of the literature.

Abstract

This review attempts to summarize data on the prevalence of thyroid pathology in the Bulgarian population over a period of 20years. Thyroid dysfunction was studied in two population-based studies (2006 and 2012). In the first, hypothyroidism was found in 6.3% and hyperthyroidism in 3.7% of the participants. The second study found overt and subclinical hypothyroidism in 3.2% and 4.5%, respectively, of females, and in 1.1% and 2% of males. TPOAb levels were elevated in 23% of females and in 9.6% of males. Nodules were found using ultrasound (US) in 23.4% of the participants in the 2006 study (in 30.1% of females and 15.0% of males), while the 2012 study showed 24.4% (32.1% of females and 15.7% of males). Recent data regarding prevalence of thyroid carcinoma in the Bulgarian population are lacking. Between 4 and 6% of thyroid biopsies produce results which have markers for malignancy. Four studies were carried out to address urinary iodine excretion levels in schoolchildren and three for those in pregnant women. Although median urinary iodine was in the iodine-sufficient range, a rising proportion of women had low urinary excretion. In the studies involving schoolchildren, excessive iodine excretion was also observed. The major strength of this review is the combination of data from different publications to give an overall baseline of thyroid epidemiology in Bulgaria. Further work is needed to map the recent trends regarding thyroid pathology in Bulgaria and the complete epidemiological dataset.