[en] From 1949-1962, regions of Kazakstan near the Semipalatinsk Nuclear Test Site (SNTS) were contaminated with high levels of radioactive fallout from atomic bomb tests carried out at the SNTS. The effective-dose is a principal criterion for the evaluation of the effect of radioactive fallout upon population. Thyroid disease prevalence may be ascertained, as a biomarker of radiation exposure and because it is of interest in itself. Some features from three studies of thyroid gland status among population living around SNTS will be reported. The first study is a case review of pathological findings of 7,271 patients from three regions adjacent to the SNTS, who were surgically treated during 1966-96; the second is a thyroid screening study of a cohort of 3000 village residents who were <20 years of age at the time of major fallout events in the Semipalatinsk region; the third is a complex molecular, morphological investigation and some approaches to rehabilitation of patients with thyroid abnormalities. Our first study revealed that there is a significant trend for the proportion of thyroid cancer to increase over time in the Semipalatinsk region of Kazakstan 20-29 years after onset of testing in 1949, which might be related to radiation exposure. There are many ethnic groups in this region. Our research among two main ethnic groups (native Kazakh and European extraction) detected that the initial level of thyroid abnormalities and thyroid cancer was higher among residents of European extraction. The total number of surgical cases increased among both ethnic groups over the years, but the numbers of cases with Hashimoto's thyroiditis and thyroid cancer increased dramatically among ethnic Kazakhs. Overall, papillary and follicular cancers predominated, but it should be noted the relatively high percentage of follicular cancers after 1982 in the Semipalatinsk region. The primary screening outcome measure was the prevaleance of thyroid nodules as determined by ultrasound. Thyroid screening participants were invited, with informed consent, from 6 exposed and 2 non-exposed villages of the Semipalatinsk region. Of those screened, 1320 were presumably exposed and 1678 presumably were not. This collaborative research project was supported by the CRDF, USA, International award no.KN2-434. Reconstructed average gamma dose was used as a preliminary index of total thyroid dose from internal and external sources of radiation exposure. Nodular thyroid gland was identified in 920 participants, of whom 500 were recommended for fine-needle aspiration biopsy (FNA). Nodule prevalence was 18% among men and 39% among women with a 3.5% per year positive gradient in prevalence overall by age at screening, and was significantly associated with estimated gamma radiation dose. Excess prevalence rate was approximately the same among men and women, with a 3-fold higher dose-specific relative risk among men compared to women. Prevalence of papillary carcinoma increased non-significantly with dose, but prevalence of follicular neoplasm was not associated with dose. Cytopathology review identified 30 papillary carcinomas in 27 cases and 10 follicular neoplasms in 10 cases. Some patients with thyroid nodular disease and thyroid cancer were referred to surgical department. They have been treated successfully by surgery or by percutaneus injection of erythrocyte pharmacocytes in accordance with our own procedure. Intraoperative thyroid tissue sampling was done to do some molecular and genetic investigation. Several aspects related to hormone status of thyroid patients, the thyroid gland function among various group of patients, morphological findings, surgical tactics and rehabilitation of patients with thyroid abnormalities living around the SNTS, will be presented. (author)