thyroid function and anti-thyroid antibodies in iranian patients with type 1 diabetes mellitus: influences of age and sex

type 1 diabetes mellitus is frequently associated with autoimmune thyroid disease (atd).genetic susceptibility for autoantibody formation in association with atd and type 1 diabetes mellitus has been described with varying frequencies, but there is still debate about its prevailing situation in iran.  we have therefore investigated the prevalence of anti-thyroid peroxidase (anti-tpo) and anti thyroglubolin (anti tg) antibodies in type 1 diabetic patients, and compared the effect of age and sex on the thyroid autoimmunity in patients with type 1 diabetes mellitus in iran. ninety one subjects with type 1 diabetes mellitus and one hundred and sixty three unrelated normal controls under the age of thirty years were recruited for the detection of anti-tpo and anti-tg. radio immuno assay and chemiluminescence methods were used for anti-tpo and anti-tg detection respectively. among 91 type 1 diabetic patients, 36 (39.6%) were positive for anti-tpo and 27(30%) were positive for antitg. anti-tpo antibodies were detected only in 6.7% of control group. comparing with those without thyroid autoimmunity, there was a female preponderance for the type 1 diabetic patients with thyroid autoimmunity (female: male, 28:14 vs. 28:20 respectively). among the type 1 diabetic patients those with thyroid autoimmunity, tended to be older (p: 0.04) and to have higher tsh concentration (p: 0.03). patients with high anti-tpo levels had longer duration of diabetes (p: 0.02). the presence of anti-tpo in 39.6% of our type 1 diabetic patients comparing with 8.5% of normal subjects confirmed the strong association of atd and type 1 diabetes mellitus.