Radioactive iodine is an effective and safe
treatment for children and adolescents with hyperthyroidism
The background of the study. Children or adolescents
with hyperthyroidism are not often treated with radioactive iodine
(I-131), because of fear of genetic damage or of thyroid or other
tumors. This study evaluated the long-term effects of I-131 therapy
in children and adolescents with hyperthyroidism.
How the study was done. Between 1953 and 1973,
116 patients <20 years old with hyperthyroidism were treated
with I-131 at a single center. In 1990–1991, 107 were located,
and, in 2001–2002, 98 were located. The patients and their
physicians provided information about the patients’ health,
including questions about thyroid dysfunction and reproductive function
The results of the study. At diagnosis, the 107
patients (80 females, 27 males) ranged in age from 3.6 to 19.8 years;
45 were ≥16 years old. From 1953 to 1965, when the mean I-131
dose was 3 to 4 mCi (111 to 148 MBq), many patients had persistent
hyperthyroidism and had to be retreated. The dose was gradually
increased to 7 mCi (259 MBq); at this dose, no patient had persistent
The 107 patients were followed for an average of 26 years (mean
age at follow-up, 40 years). One year after treatment, 32 percent
had hypothyroidism. Among the 98 patients followed for an average
of 36 years (mean age at follow-up, 48 years), 98 percent had hypothyroidism.
Six patients had recurrent hyperthyroidism 10 to 21 years after
Sixty-two women had 179 pregnancies. The outcomes were: spontaneous
abortion, 19; induced abortion, 5; ectopic pregnancy, 2; molar pregnancy,
1; stillbirth, 3; and live birth, 152. Few had congenital anomalies.
Among the women who had no pregnancies, most were single. Eighteen
of the 27 men had fathered 36 pregnancies, with 33 live births.
One patient had a carcinoma of the colon and one a carcinoma of
the breast. No patient had a thyroid carcinoma or leukemia.
The conclusions of the study. Most children and
adolescents with hyperthyroidism treated with I-131 have hypothyroidism,
their reproductive capacity and outcomes are normal, and none have
The original article. Read CH Jr, Tansey MJ, Menda
Y. A 36-year retrospective analysis of the efficacy and safety of
radioactive iodine in treating young Graves’ patients. J Clin
Endocrinol Metab 2004;89:4229-33.