Thyroid consequences of the Chernobyl nuclear power station accident on the Turkish population.

Abstract

The Chernobyl accident caused widespread effects across Europe and huge areas were radiocontaminated. The major impact of the accident on human health was a sharp increase in childhood thyroid carcinoma and autoimmune thyroid diseases in exposed populations. The thyroidal effects of the Chernobyl accident have been investigated in most European countries, except Turkey. The aim of the current study was therefore to determine the thyroidal consequences of the Chernobyl nuclear power station accident in a selected Turkish population. This study was designed as a sectional, area study, between October 2000 and March 2001, in two different regions of Turkey. According to the data of the Turkish Atomic Energy Authority, the eastern part of the Black Sea region was the most radiocontaminated area in Turkey at the time of Chernobyl accident, while Middle Anatolia was not seriously affected. Thus, Rize city, which is located in the eastern Black Sea region, served as a study area, and 970 adolescents, living in this region, comprised our study group (group R). On the other hand, Beypazari, which is located in Middle Anatolia, was chosen as the control region, and 710 adolescents living in this location were enrolled into the study as controls (group B). During the study, thyroid ultrasounds were performed in all subjects and thyroid volumes were calculated. World Health Organization and International Council for Control of Iodine Deficiency Disorders criteria were used for the determination of goiter. Thyroid fine-needle aspiration biopsy with ultrasound guidance was performed when a nodule was detected. Blood samples for thyroid function tests and thyroid autoantibodies, and urine samples for urinary iodine excretion were collected from all subjects. Thyroid function tests were similar in both groups, but thyroid volumes were found to be higher in group B (13.93+/-5.04 vs 17.66+/-5.58 ml; P<0.001). The prevalence of goiter was found to be 28.25% in group R and 61.95% in group B (P<0.001). Thyroid nodules were determined in 6.28% of subjects in group R and 4.22% of subjects in group B (P=0.065). No malignant lesions were found in either of the regions. Although the percentage of autoantibody-positive subjects did not differ between groups (21.25% in group R vs 18.72% in group B), the mean anti-thyroglobulin level was found to be higher in group R (63.25+/-378.60 vs 51.97+/-333.32 IU/ml; P<0.001) and the mean anti-thyroid peroxidase level was higher in group B (24.14+/-219.09 vs 48.82+/-568.50 IU/ml; P<0.001). The iodine status of the selected regions was found to be significantly different (median urinary iodine excretion was 131 microg/l in Rize and 54 microg/l in Beypazari). Although there was a slight increase in nodule prevalence and thyroid antibody-positive subjects in the study group, it is hard to conclude that Turkey was affected by the Chernobyl accident. These results, at least the significant differences with regard to the prevalence of goiters between groups, may reflect the different iodine status of the selected regions.