title: Changing values for the normal thyroid radioactive iodine uptake test.
abstract: The normal range for thyroid radioactive iodine (RAI) uptake values in the Minneapolis area has shifted twice in the past 20 years. The mean 24-hour thyroid RAI uptake value in 29 normal subjects was 20.5% +/- 6.1% (SD) in 1975, whereas only four years previously it was found to be 11.5% +/- 4.4% (SD) in 51 normal subjects. In a previously published study, the mean thyroid RAI uptake value in normal subjects in this area was 25% +/- 8% (SD) in 1957. The iodine content of commercially baked white bread currently available in this area was found to average only 26 microgram per single slice of bread; the change in the mean 24-hour thyroid RAI uptake value that we observed between 1971 and 1975 is most likely due to a marked reduction in this source of dietary iodine.
mesh_terms: D001939:Bread / Q000032:analysis; D005503:Food Additives / Q000008:administration & dosage; D006801:Humans; D007455:Iodine / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism; D007457:Iodine Radioisotopes; D008910:Minnesota; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000378:metabolism*
chemical_list: D005503:Food Additives; D007457:Iodine Radioisotopes; D007455:Iodine