Iodine status in children with intestinal failure.

Objectives: Children on long-term parenteral nutrition (PN) are at high risk of iodine deficiency (ID). However, most available information comes from cross-sectional studies. We investigated the iodine status, associated factors, and prevalence of hypothyroidism in children with intestinal failure (IF) who were followed up longitudinally.

Methods: This was a cohort study of children with IF monitored for urine iodine concentration (UIC), iodine intake, serum selenium concentration, and thyroid function in an intestinal rehabilitation program. The outcome variable ID was defined as a UIC value < 100 μg/L. Adjusted generalized estimating equations were used to assess the effects of the exposure variables on the UIC.

Results: Twenty-four patients aged 62.7 (39.1; 79.7) months who received PN for 46.5 (21.5) months were included. The average energy supply was 81.2 kcal/kg/day, 77.6% of which was provided by PN. An average of 5.2 UIC measurements per patient were performed. ID prevalence decreased from baseline (83.3%) to the last assessment (45.8%). Three patients had hypothyroidism secondary to iodine and selenium combined severe deficiency. Iodine intake from enteral or oral nutritional formulas was positively associated with UIC (β = 0.71 [0.35, 1.07]; p < 0.001). Meeting approximately 80% of the estimated average requirement for iodine from nutritional formulas resulted in a greater probability of normal UIC values.

Conclusion: ID is highly prevalent in children with IF who receive long-term PN and its frequency decreases with iodine intake from nutritional formulas. Severe combined iodine and selenium deficiencies are associated with the development of hypothyroidism in these patients.