• Changes in the thyroid gland after radiation exposure from the Chernobyl nuclear power plant accident in 1986
  
• Examination of other possible risk factors, including dietary iodine intake during and after 1986 and the ingestion of potassium iodide for thyroid protection shortly after the accident
  

OBJECTIVES:

• Carry out valid and credible assessments of the early and late morphologic and functional changes in the thyroid glands of individuals exposed to radiation from radioactive materials released as a result of the Chernobyl nuclear power plant accident in 1986.
• Examine other possible risk factors, including dietary iodine intake during and after 1986 and the ingestion of potassium iodide for thyroid protection shortly after the accident.

OUTLINE: Participants complete a questionnaire about residence (at the time of the Chernobyl nuclear power plant accident), health, diet, lifestyle, and family history of thyroid disease. Participants also undergo diagnostic thyroid examinations, including palpation, ultrasound scanning, and thyroid hormone and other laboratory testing. Fine-needle aspirations are performed, if indicated. Some participants may also undergo urine sample collection to determine urinary iodine content. Participants are reexamined every 2 years for at least 6 years for thyroid cancer morbidity and mortality.

If the participant was under 10 years of age at the time of the nuclear power plant accident (or if the mother was pregnant with the participant at the time of the accident), the questionnaire is completed by the participant's parents.