WASHINGTON — Potassium iodide pills should be available to everyone age 40 or younger — especially children and pregnant and lactating women — living near a nuclear power plant, says a new report from the National Academies' National Research Council. Potassium iodide can prevent thyroid cancer caused by exposure to radioactive iodine, a compound that could be released during a severe accident at a nuclear power plant. Potassium iodide will not protect the body against other types of radioactive isotopes released during nuclear-reactor incidents or those likely to be used in a so-called dirty bomb, added the committee that wrote the report.
For potassium iodide to be most effective, it must be taken within a few hours before or after exposure to radioactive iodine, the report says. Further protection from risk should be accomplished by evacuation and by control of contaminated milk and food. The report calls on states and municipalities to decide how to stockpile, distribute, and administer potassium iodide tablets. Federal agencies, however, should keep a backup supply and be prepared to distribute it to affected areas in the event of a nuclear incident. The U.S. government also should provide financial support to help states implement plans for distributing potassium iodide. And because potassium iodide pills keep for a long time if stored properly, the Food and Drug Administration should consider extending the allowable shelf life of tablets being amassed for an emergency.
"Because conditions at nuclear power plants vary so much, it must be up to local planning agencies to determine the appropriate distribution strategy and areas in which to dispense potassium iodide," said committee chair David J. Tollerud, a professor at the University of Louisville, Louisville, Ky. Plans for pill distribution have mainly focused on a 10-mile-wide "emergency planning zone," but the report says a specific incident might call for a smaller or larger zone of distribution.
Potassium iodide pills work by quickly "filling" the thyroid with nonradioactive iodine, thereby blocking absorption of radioactive iodine. When absorption of radioactive iodine does occur, it can be passed from mother to fetus via the placenta, or to a nursing baby through breast milk. And fetuses, infants, and children are more biologically sensitive than adults to radioactive iodine. For these reasons, infants, children, and pregnant and lactating women are considered to have the most need for potassium iodide pills if exposure to radioactive iodine is likely. The pills are not recommended for people over 40 because epidemiological studies have not demonstrated a risk of radiation-induced thyroid cancer in this age group, while their risk of side effects from potassium iodide is higher.
Public education should be a key part of any potassium-iodide distribution plan, the committee added. It also recommended that a national program be developed to monitor the health of individuals who take potassium iodide if a nuclear incident occurs. The report calls for additional research on the effects of exposure to radioactive iodine and ways to minimize them. Data from the Chernobyl accident are available, although the report notes that a similar accident is highly unlikely in the United States given the design and safety features of reactors here.
Information for the general public about the report's findings and recommendations can be found online at http://dels.nas.edu/potassium_iodide. The study was mandated by Congress and sponsored by the U.S. Centers for Disease Control and Prevention. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provides science and technology advice under a congressional charter.
Call Bill Kearney, director of media relations, or Heather McDonald, media relations assistant, for more information from the National Academies Office of News and Public Information.
