Validity and Reproducibility of the Iodine Dietary Intake Questionnaire Assessment Conducted for Young Polish Women

The aim of this study was to analyse a designed brief iodine dietary intake questionnaire based on a food frequency assessment (IOdine Dietary INtake Evaluation-Food Frequency Questionnaire—IODINE-FFQ), including the assessment of validity and reproducibility in a group of 90 Polish women aged 20–35 years. Participants collected 3-day dietary records and filled in the IODINE-FFQ twice (FFQ1—directly after the dietary record and FFQ2—6 weeks later). The analysis included an assessment of validity (comparison with the results of the 3-day dietary record) and of reproducibility (comparison of the results obtained twice—FFQ1 and FFQ2). In the analysis of validity, a Bland-Altman index of 5.5% and 4.4% was recorded, respectively for FFQ1 and FFQ2. In the analysis of reproducibility it was 6.7%, but the share of individuals correctly classified into tertiles was over 70% (weighted κ of 0.675). It was stated, that assessment of IODINE-FFQ revealed a satisfactory level of validity and reproducibility in the analysis of Bland-Alman plot. The IODINE-FFQ may be indicated as a tool for the assessment of iodine intake in the young women in Poland, however further studies should be considered in order to obtain the practical tool for public health specialists. Due to the lack of validated iodine-specific food frequency questionnaires for countries of Eastern Europe, the IODINE-FFQ may be adjusted for courtiers other than Poland including iodine-fortified products.