Iodine supply in children from different european areas: the Euro-growth study. Committee for the Study of Iodine Supply in European Children

Background: In many areas of Europe iodine deficiency disorders still exist. Urinary iodine excretion is a valuable tool in characterizing the iodine supply of a population. However, there is a continuing discussion on the most appropriate parameter to measure urinary iodine excretion. Methods: In 247 children (ages 3-5 years) from six European centers, spot urine samples were analyzed for urinary iodine concentration and urinary iodine- creatinine ratio. Results: The median values of urinary iodine concentration from the six centers were very similar (90-106 μg/l) corresponding to a normal or marginal iodine supply according to the criteria of the World Health Organization. However, the median values of the urinary iodine- creatinine ratio from the six centers differed significantly (143-445 μg/g, P < 0.001). The different results of the two urinary parameters to assess urinary iodine supply were due to large significant differences in the urinary creatinine concentration reported by the various centers, which probably reflect marked differences in water intake. Conclusions: Iodine deficiency is still a significant health problem in many European countries. In comparable and homogeneous population subgroups (even from different countries), the urinary iodine-creatinine ratio appears to be a much better parameter for assessing iodine supply than urinary iodine concentration.