[Hypothyroidism and type 1 diabetes mellitus]

ABSTRACT

Type 1 diabetes mellitus is frequently associated with autoimmune thyroid disease. Genetic susceptibility to autoantibody formation in association with autoimmune thyroid disease and type 1 diabetes mellitus has been described with varying frequencies. To investigate the prevalence of anti-thyroid peroxidase [anti-TPO] and also the overt and subclinical hypothyroidism in type 1 diabetic patients. In this case-control study, 65 subjects with type 1 diabetes mellitus and 65 unrelated normal controls were recruited for detection of anti-TPO and thyroid-stimulating hormone [TSH]. Radioimmunoassay [RIA] was used for anti-TPO and TSH detection. Out of 65 type 1 diabetic patients, 18 [27.7%] were positive for anti-TPO and 18 [27.7%] with abnormal serum TSH level. Among the patient group, 11 [16%] were found to have overt hypothyroidism and 7 [10.8%] with subclinical hypothyroidism. The mean anti-TPO levels were higher in patients with overt hypothyroidism [238.18 +/- 223.69 U/ml] than in patients with subclinical hypothyroidism [36.38 +/- 22.46 U/ml]. Of a total of 11 patients with overt hypothyroidism, 9 [81.1%] showed abnormal anti-TPO levels, whereas positive anti-TPO was detected in 57% [4 out of 7] of patients with subclinical hypothyroidism. The presence of anti-TPO in 27.7% of type 1 diabetic patients confirmed a strong association between autoimmune thyroid disease and type 1 diabetes mellitus, Thus, for early detection of autoimmune thyroid disease in patients with type 1 diabetes mellitus, the measurement of anti-TPO and TSH, preferably at the onset of disease, is recommended