Hyperthyroid Follow-Up Study

Background: Hyperthyroidism is a common disease. It is very common for women. It is usually treated with Radioiodine (I-131). Some people think that this might cause cancer, even many years later. Past studies of people with hyperthyroidism have not been clear about cancer risks after I-131. Researchers want to look at a group of people with the disease who got I-131 many years ago. They want to look at how their health was months and years later. Objective: To learn more about disease risks in relation to radiation from I-131 treatment for hyperthyroidism. Eligibility: People who were part of the previous study. These are people who were diagnosed with hyperthyroidism at U.S. and U.K. hospitals from 1946 to 1964. About 95% of the participants have already died. Design: Researchers will examine data already collected by the past study. This includes data on participants later cancers and other health outcomes after they had I-131 treatment. Researchers will compare that data to a National Death Index search. This was already done for data up through 2003. This study will cover 2004 2014. Researchers will not be in touch with study participants or their next of kin....