The authors decided to assess the incidence of impaired thyroid function in a group of 252 children and adolescents followed up in the diabetological centre of the Slovak Republic at the First Paediatric Clinic of the Comenius Medical Faculty and Paediatric Faculty Hospital in Bratislava. They examined prospectively 252 children with IDDM, 140 girls and 112 boys. Four children were treated on account of primary hypothyroidism before the beginning of the investigation, three children suffered in addition to type 1 diabetes also from Down’s syndrome. Various forms of thyropathy were diagnosed in 18 (7.1%), in 14 instances a newly detected disorder was involved. Severe hypothyroidism was detected also in two of three patients who suffered in addition to diabetes also from Down’s syndrome. The authors recommend screening of thyroid functions after manifestation of diabetes mellitus type 1 and after compensation of the metabolism. Even in case of normal values of thyroid functions during the initial examination they consider it necessary to check it regularly after two-year intervals, in particular in patients with a high risk of development of thyropathy such as e.g. in children with Down’s syndrome.

        Key words: diabetes mellitus type 1, hypothyroidism, hyperthyroidism