Analysis of current recommendations and criteria of the world health organization for the assessment of iodine deficiency conditions

Abstract

The incidence of endemic goiter in the Orel district of Russia has been studied in order to assess the informative value of the new WHO classification for identification of iodine deficiencies (1994). A total of 2103 children living in three rural regions, two of which were polluted with low-dose radiation after the Chernobyl accident, have been examined in 1992-1996. The incidence of goiter and thyroid dysfunction in the newborns corresponded to grave endemia, and the median of blood thyroglobulin was moderately increased in the region with the highest pollution (5 to 15 Ci/km2 for 127Cs), characterized by a slight iodine deficiency. In a less contaminated region (1 to 5 Ci/km2) with a similar level of iodine deficiency, incidence of goiter, and median of blood thyroglobulin the incidence of thyroid dysfunction in the newborns was moderate. In a pure region, despite a more evident iodine deficit and a compatible increase of the median of blood thyroglobulin, the incidence of endemic goiter and thyroid dysfunction of the newborns was the minimal. Hence, the values of the analyzed iodine deficit indicators did not correlate with the actual iodine deficiency in all the regions examined. These differences suggest a possible contribution of strumogenic factors other than iodine deficit to the formation of goiter endemia in the examined district. The detection of these factors in the environment is needed for objective evaluation of the causes and severity of the endemic process and for the development of differentiated approaches to the prevention and treatment of thyroid abnormalities in the population exposed to radiation.