Læknablaðið : fylgirit - 01.06.1982, Side 40

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THYROID DISORDERS IN TYPE 1 (INSULIN-DEPENDENT) DIABETICS
IN ICELAND. R. Danielsen, Diabetic Clinic, Landspítalinn,
University Hospital, Reykjavik, Iceland.
The prevalence of all clinically verified thyroid disord-
ers ^TD) in all Type 1 diabetics in Iceland was assessed and
various clinical factors, complications and HLA-types were
also studied. At the end of the year 1979 there were 266 dia-
betics in the country, all on record at the Diabetic Clinic.
Information on TD in these patients was sought in these files
and also in the hospital records of the three largest hospitals
in Iceland as patients with two endocrine disorders would prob-
ably at one time be investigated/treated at one of these. In-
formation on diabetic complications (retinopathy and protein-
uria) and on HLA-types was available from previous studies.
A total of 15 patients (5,6%) also had TD; 12 (80%) were femal-
es, indicating that every tenth Type 1 diabetic female in Ice-
land also has a TD. Four of the pts were hypothyroid (all fe-
males), 7 hyperthyroid (6 females, 1 male) and 4 pts had other
TD (Hashimoto's thyroiditis, cystic glandular thyroid, struma
adenoma folliculare, adenocarcinoma papilliferum) . Meaii (± sd)
age at diagnosis of diabetes and TD was 37.9±11.7 and 32.1±
9.9 years respectively. When TD preceéded diabetes it was usu-
ally hyperthyroidism; conversely, hypothyroidism was most fre-
quent. Of 15 pts, 6 (40%) had a relative with Type 1 diabetes
and 7 (46.7%) had a positive family history of TD. The relative
risks, calculated from 12 HLA-typed pts, were 4.2 and 2.3 for
B15 and B8 respectively. The mean daily insulin dosage was 39.1
± 17.5 units; excluding three pts using over 60 units, the re-
sults are 31.8± 9.8 units. Thus 10 of 15 pts used less than 40
IU and of these 6 used less than 35 IU/24 hours. The mean dur-
ation of diabetes was 12.1±10.4 yrs. Of 15 pts 6 (40%) had
retinopathy; 1 pt proliferative, 5 background lesions and in
4 of these diabetes had existed for 20 or more years. Blindness
or proteinuria was not found in the group. By histological and
clinical reviewing,13 (11 females, 2 males) of the 15 pts were
concluded to have "autoimmune" TD.