[Analytical problems of iodine defficiency examination in Polish Nation-wide deficit control program]

The environmental iodine deficiency has been a serious problem in the Polish health care system for many years. In many European countries the prevention of iodine deficiency-related health deficits in population scale is based on edible salt supplementation with KI. In the decade of the 80-ties the iodine supplementation program in Poland was stopped, which has caused a subsequent increase in prevalence of goiter and iodine deficiency-related hypothyreosis. These diseases were observed in many regions of Poland, including the areas beyond regions of formerly known iodine deficiency endemias. In order to control the whole Polish population, iodine consumption deficit in1991 the "Polish Program of Iodine Deficiency Control and Prevention of Iodine Deficiency-related Disorders" has been established in the year 1991. In 1992--1996 a common iodine supplementation of salt used for general consumption was 20 mg KI/kg of NaCl, and in 1997 the mandatory supplementation of salt was 30 (+10) per kg of salt which has been introduced for the whole country. This paper reports the results of iodine excretion assays in school children 6-12 years old, in the years 1993--94, 1996--97 and 1999--2002 respectively. The obtained collections of iodine urine concentrations have shown distributions with a remarkable rightward skewness. Normalization of distributions required logarythmic transformation. The quartile values obtained for data collections from years 1992--94, 1996--97 and 1999--2002 have shown that in 5-7 years of iodine deficiency prevention program yielded increase in iodine excretion in morning urine samples by about 37.8 microg, while the iodine excretion median values increased from 63.5 mg/L in years 1992--1994 to 94.0 mg/L in years 1999--2001, respectively. The lower limits of iodine excretion ranges calculated as the mean value minus 2SD of transformed data for the years 1992--1994 amounted to: 7.74 mg/L and for the years 1999--2001 amounted to 14.1 microg/l, respectively. Assessing percent of children obtaining low iodine suplementation then recommended (below 50 mg/L in urine sample) amounted to 35.8% in years 1992--1994 and 15.4% in years 1999--2001 respectively.