Principles, main goals and methods of the nationwide program: "investigations on iodine deficiency and model of iodine prophylaxis in Poland".

The main reasons to start investigations on IDD in Poland as a nationwide project of the Ministry of Health and Welfare sponsored by the State Committee For Scientific Research and Foundation for Polish Science were: cessation of iodizing of kitchen salt in Poland in 1980, increase of the incidence of goitre in the population and hyperthyrotropinemia in newborns, results of the survey undertaken after Chernobyl disaster indicating an increase of goiter incidence (Nauman et al.) and results of the pilot study (Gutekunst, Gembicki, Kinalska and Rybakowa) indicating an increase of thyroid volume and diminishing of iodine excretion in urine of children in Kraków, Białystok ad Poznań regions. Therefore the main goals of the project were as follows: to evaluate IDD in Poland on the population basis, to map goiter incidence and iodine deficiency in geographic areas, to evaluate a voluntary model of iodine prophylaxis in Poland (20 mg of KI/kg of salt). The investigations were carried out in 19330 children (48.7% of boys and 51.3% for girls) in age group 6-13 years, attending 111 coeducational randomly selected schools from all the country. This number represents 0.35% of children subpopulation in the above age-groups. For practical purposes local coordinating centers at the relevant Departments of Endocrinology and Board of Coordinators were set up. The programme of survey included: filling the questionnaire by children's parents, thyroid palpation and classification according to WHO and ICCIDD criteria, thyroid volume determination by means of ultrasonograph Kontron Sigma 1 L with linear transducer 7.5 MHz, determination of iodine in casual morning urine sample using Sandell and Kalthoff method. Determination of iodine concentration in urine was performed in each case of goiter and in the same number of children without goiter. The results were segregated according to coordinating centers and according to 6 geographical areas of the country. The results were calculated according to the descriptive statistics using Student's test, Chi-square test F-test and Leven's test. The results segregated according to geographic areas were tested by means of analysis of variance using the linear model. The final results of the programme are presented in the next papers.