Iodine Deficiency Hypothyroidism Among Children in the United States - 21st Century Resurgence?

Background/Objective: Iodine deficiency hypothyroidism is an important cause of neurocognitive and motor impairment in children globally. In the United States, universal salt iodization, which began in the 1920s, led to a dramatic decline in iodine deficiency hypothyroidism. However, iodine deficiency may be reemerging due to increased consumption of noniodized salts, decreased dairy iodine concentrations, and decreased intake of iodine containing foods due to food allergies, dietary preferences such as vegan diets, or restrictive food intake disorders. Case Report: We present a case series that challenges the existing clinical paradigm for hypothyroidism and describe 3 patients without underlying thyroid dysfunction who were diagnosed with iodine deficiency hypothyroidism over an 18-month period beginning in February 2021 in Northeastern United States. Prior studies reported 2 additional cases diagnosed in that same time frame at our clinical center. Discussion: We report significant heterogeneity in clinical presentation: 3 patients had large goiters, 1 had a mild goiter, and 1 patient had no goiter. Biochemical tests were also variable and included a wide range of thyroid stimulating hormone elevations. Conclusion: We suggest that a spot urine iodine concentration, combined with an elevated serum thyroglobulin level, can be an alternative to a 24-hour urinary iodine excretion for the diagnosis of iodine deficiency hypothyroidism given the clinical challenges of obtaining the latter. Thyroid function normalized in all patients with iodine supplementation.