[Thyroid hormone anomalies in patients with insulin-dependent diabetes mellitus and circulating antithyroid microsomal antibodies].

In insulin-dependent diabetes mellitus (IDDM) several organ-specific autoantibodies are found in addition to pancreatic islet cell autoantibodies. In the present study we researched the presence of thyroid microsomal antibodies (anti-TMS) in 33 young patients with IDDM and evaluated contemporaneously their thyroid function. 5 patients (15.4%) are found with significant levels of circulating anti-TMS, among them 4 (12.1%) were also subclinical hypothyroid. However 6 other patients are found with mildly altered thyroid hormone pattern in absence of circulating anti-TMS. Basal and TRH-stimulated TSH were significantly higher, whereas serum FT4 was significantly lower, in patients with IDDM and circulating anti-TMS than in patients with IDDM but without anti-TMS. These observations indicate a significant incidence of mild or subclinical hypothyroidism in patients with IDDM and anti-TMS. Thus the screening for anti-TMS is recommended in all patients with IDDM, then thyroid hormone pattern of anti-TMS positive patients must be periodically followed.