[Status of iodine nutrition of children until 1 year: consequences on the thyroid function]

Iodine deficiency remains a major public health problem mainly in least-developed countries but also in many industrialized countries.

The present study aimed at: (1) evaluating the status of iodine nutrition of children until 1 year in the North region of France; (2) studying risk factors for iodine deficiency; (3) evaluating relationship between iodine deficiency and thyroid disorders.

This prospective study was conducted between 1st january and 31st May 2005 in the children's hospital of Lille (North of France) and all hospitalized children until the age of 1 year were enrolled. Urinary iodine assessment was obtained for 95 (83%) of the 114 infants hospitalized during the study period and TSH value was also determined in 57 (60%) of these 114 infants.

Median urinary iodine concentration was 328 microg/L (range: 12-1580). Twenty-four (25%) of 95 infants had a high urinary iodine excretion (urinary iodine greater than 400 microg/L). Nineteen (20%) of the 95 infants were iodine deficient (urinary iodine less than 100 microg/L): severe iodine deficiency (less than 20 microg/L; n=5; 5%), moderate iodine deficiency (20-49 microg/L; n=6; 6%), mild iodine deficiency (50-99 microg/L; n=8; 8%). No relationship was found between iodine status and the following data: age, sex, familial thyroid disease history, term and type of delivery, nutritional status, type of feeding at inclusion, chronic disease, familial socioeconomic status. TSH value was high (greater than 5 microU/mL) in 7 (12%) of the 57 infants. Only 1 of these 7 infants was iodine deficient. Only 1 of the 19 infants with iodine deficiency had a high TSH value.

Iodine status is not optimal in our population of hospitalized children until the age of 1 year. There is no clear relationship between iodine status and thyroid function.