A progress report of the Marshall Islands Nationwide Thyroid Study: An international cooperative scientific study

The objective of this report is to present a summary of progress of the Mar shall Islands Nationwide Thyroid Study. As well known, the US atomic weapon s testing program in the Pacific was conducted primarily between 1946 and 1 958 in the Marshall Islands. The nuclear tests resulted in radioactive cont amination of a number of atolls and resulted in exposure of Marshallese to undefined levels before our study. Little information has been paid td heal th consequences among residents of the nearly twenty inhibited atolls excep t for some information about nodular thyroid disease which was reported on by an US group. In a cooperative agreement with the Government of the Marsh all Islands, between 1993 and 1997 we studied the prevalence of both thyroi d nodules and thyroid cancer among 4766 Marshallese potentially exposed to radioiodines from bomb test fallout. That group represents more than 65% of the population at risk. We diagnosed 45 thyroid cancers and 1398 benign th yroid nodules. In addition, 23 study participants had been operated on prio r to our study for thyroid cancer. Presently, we are developing a database of information to estimate radiation doses and planning a statistical analy sis do determine if a dose-response relationship exists. These data will be important for the health promotion of exposed people all over the world in cluding Hiroshima, Nagasaki, Semipalatinsk, Chernobyl and other locations. A timely completion is important for purpose of assisting Marshallese as we ll as to add the global understanding of radiation induced thyroid cancer.