Increased prevalence of hyperthyroidism as an early and transient side-effect of implementing iodine prophylaxis

ObjectiveTo assess the prevalence of hyperthyroidism just after implementation of iodine prophylaxis among adults from an area with iodine deficiency.Study design and subjectsA total of 1648 adults (age 16 years and older) were sampled from an area of southern Poland during two nationwide epidemiological surveys. Of these, 1424 adults with negative medical history for thyroid disorders qualified for final analysis. The authors compared thyroid dysfunction in participants prior to (1989–1990) and after implementation of iodine prophylaxis (1997–1999).SettingThe southern part of Poland.ResultsWe found an increase in the serum concentration of anti-thyroid microsomal antibodies from 4.9% in the years 1989–1990 to 12.1% after introduction of iodised household salt (P < 0.0001). The prevalence of hyperthyroidism (defined as thyroid-stimulating hormone < 0.4 μU ml− 1) significantly increased in the equivalent period from 4.8 to 6.5% (P = 0.009).ConclusionsWe concluded that a sudden rise in iodine intake after implementation of iodine prophylaxis among adults from the area with iodine deficiency may lead to an increase in thyroid autoimmunity and prevalence of hyperthyroidism. Those possible early side-effects appear to be only temporary and are acceptable when compared with the evident benefits of adequate iodine intake.

Azathioprine in the treatment of thyroid-associated ophthalmopathy

Azathioprine is used in the treatment of thyroid-associated ophthalmopathy, but its effectiveness has not been evaluated. In the present study 20 patients with moderately severe ophthalmopathy were recruited; 10 patients received azathioprine and the other 10 matched patients served as controls. During the treatment period (lasting 1 year) and 1 year later, no changes were detected in exophthalmometer readings, visual acuity or measurement of palpebral aperture. Differential intraocular pressure fell with time in both groups. Azathioprine treatment did not significantly influence these parameters, although it did induce significant decrease in thyroid microsomal antibodies and in thyroid-stimulating hormone binding inhibiting immunoglobulin index. The study demonstrates that thyroid-associated ophthalmopathy of moderate severity, often improves with time without treatment. Azathioprine is not an effective treatment for patients with moderately severe thyroid-associated ophthalmopathy. The study emphasises the necessity for an adequately matched control population in the evaluation of therapy.

Thyroid-infiltrating lymphocytes, thyroid function, and HLA-DR in juvenile autoimmune thyroiditis

Eighteen patients with juvenile autoimmune thyroiditis were studied. At diagnosis 8 (44%) of the patients were euthyroid and 10 hypothyroid, whereas at the end of 6 to 12 months follow-up, 12 (66%) were euthyroid and 6 hypothyroid. All the patients were HLA-typed. The frequency of HLA-DR4 was increased in the patients when compared with the normal population, 63 vs 28% (p < 0.01). An analysis of thyroid-infiltrating mononuclear cells revealed that the majority of the thyroid-infiltrating lymphocytes were T cells. More T lymphocytes and fewer B lymphocytes and HLA class II positive lymphocytes were found among the thyroid-infiltrating mononuclear cells in euthyroid than hypothyroid patients. The numbers of thyroid-infiltrating B lymphocytes correlated with the levels of thyroid microsomal antibodies. No correlation was found between thyroid function and thyroid antibodies.