thyroid, which leads to a higher concentration in the gland. Because intake of radioactive iodine is relatively constant with age, radiation doses are usually greater in smaller children. Both factors are considered in determining the multipliers given in the age panel of Table 2. A proportion of exposure came from sources other than milk (often as much as one-third of the total) so a different multiplier should be assigned to the non-milk drinker. Persons who consumed more milk than the average are allocated a multiplier of __. Finally, a gender-specific factor is included because females are more sensitive to cancer induction by a factor of about __.

Procedure: Multiply the 4 factors obtained from Steps 2 and 3 to determine your relative risk value.

Explanation: The product of the 4 factors is a number that indicates the risk of developing thyroid abnormalities (cancer in particular) as a result of exposure to I-131 from the nuclear weapons testing. This value is risk relative to the group to males aged 5-14 and above at the time of the testing. Men in that age group are the ''reference category" because, of all the age and gender combinations, they represent the group with the lowest risk of exposure-induced disease (older men were of minimal, if not zero, risk). The risk of those in the reference category is about ___ on the scale developed here. The risk anyone else might calculate could be as high as ___. Example calculations are provided to assist the reader.