Iodinated Contrast Agents and Risk of Hypothyroidism in Young Children in the United States. Issue 5 (May 2019) - Jick, Susan S.
Abstract : Background: Although it is generally acknowledged that exposure to iodine contrast agents can interfere with thyroid function, little is known about the incidence of iodine-induced hypothyroidism in young children (younger than the age of 4 years). Study Objectives: This was a retrospective cohort study to estimate the incidence rate of detected hypothyroidism in a US-based general population of pediatric patients exposed to an iodinated contrast agent. Setting: The study was conducted in Kaiser Permanente Northern California, an integrated health care delivery system. Study Population: This study included 2320 pediatric patients younger than 4 years of age who had a diagnostic procedure with an iodinated contrast agent during years 2008 to 2016. Results: Among 2320 young children who met our study criteria, we identified 34 who met the initial criteria to be a case of hypothyroidism. The incidence density ratio for all hypothyroidism in iodine contrast agent–exposed patients was 1.33 per 1000 person months (95% confidence interval, 0.9–1.8). Most cases appeared to have subclinical hypothyroidism. The rate was higher for the probably iodine-induced cases (0.90 per 1000 person months) compared with cases with a possible alternate etiology (0.43 per 1000 person months), for males compared with females, and among children who had a heart catheterization compared with those with a computed tomography scan. It was also highest among the youngest children (younger than 3 months old), and decreased with increasing age. Discussion: Our finding of hypothyroidism in young children exposed to iodine contrast agents (1.33 per 1000 person months [95% confidence interval, 0.9–1.8]) is broadly consistent with the sparse literature on this outcome. Abstract : Supplemental digital content is available in the text.