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Bülow Pedersen et al., Aalborg and Glostrup, Denmark, did a cross-sectional comparative
population study in 4649 subjects randomly selected from the general population of two
geographical areas with mild (median urinary iodine 61 µg/l) and moderate (45 µg/l) iodine
deficiency. They found no difference in the prevalence of TPO-Ab and Tg-Ab between the two
areas. In both populations the 2 types of antibodies were more frequently measured in females
than in males of the same age group and increased in females with increasing age. Tg-Ab was
more often measured in non-smokers than smokers, but the prevalence of TPO-Ab was independent
from smoking. The authors conclude that the distribution of thyroid autoantibodies in moderate
and mild iodine deficiency is similar, is more frequent in females than males and increases with
age in females. A negative association was found between smoking and Tg-Ab. (Comment: As in
Graves' disease smoking is related to a higher prevalence of ophthalmic disease (OD) whereas
smoking is apparently also associated with a decreased prevalence of Tg-Ab, it would be
interesting to know if the presence of Tg-Ab suppresses the development of OD. In this respect
one wonders if the prevalence and/or concentration of Tg-Ab is higher in Graves' patients
without OD than with OD?? Who takes this up??). Mazziotti et al., Naples, Italy, evaluated
thyroid- autoimmunity and function in 112 patients (84 males, mean age 50 years),7 years after
a 12 months period of treatment with recombinant IFN-a for hepatitis C. They found that
autoimmunity (presence of circulating thyroid autoantibodies) had developed in 32% of patients.
Further analysis showed that absence of antibodies at the end of therapy indicated that no
autoimmunity would develop in the years thereafter. However when present, there was an
increased risk for development of subclinical or overt thyroid hyper/hypo function. (Comment:
This study is of practical value in that it seems to tell us that when thyroid autoantibodies
are absent after treatment, frequent follow-up for thyroid function seems to be less mandatory).
Gasnier et al., Munich, Germany, argued that mild selenium deficiency may contribute to the
development and maintenance of thyroid autoimmunity and therefore performed a blinded, placebo
controlled prospective study in 72 female patients with autoimmune thyroiditis and presence of
circulating TPO-Ab and/or Tg-Ab, both >350 U/ml. The treatment group (36 patients) received 200
µg sodium selenite orally/day for 3 months and the other group of 36 patients a placebo. After
3 months of treatment 9/36 patients in the treatment group had completely normalized antibody
titers versus 2/36 in the placebo group (p = 0.02). In these 9 patients ultrasound of the
thyroid showed a normalized pattern. In the treatment group the mean TPO-Ab concentration
decreased by 49% versus 9% in the placebo group. (Comment: These are provocative results and
if confirmed, selenium treatment to prevent or suppress autoimmunity may become an option).
Gärtner et al., Munich, Germany, tested the frequency of autoimmune thyroiditis in 58 patients
with polycystic ovary (PCO) syndrome and compared results with 106 age matched female control
subjects. In the control population 10% had TPO-Ab and/or Tg-Ab, whereas in the patients group
this figure was 43.1% (p = 0.0001). In 20/58 of the PCO group, hypoechogeneity of the thyroid
ultrasound was present, 8 patients were substituted with LT4 and 2 were operated in the past
for Graves' disease. The results of this study demonstrate a 4-fold higher prevalence of
autoimmune thyroiditis in females having PCO. As a possible mechanism the authors suggest that
this increased risk might be caused by the elevated estrogen-/low progesterone levels in this
patients group.
Several reports were on the relationship between thyroid autoimmune disease and diabetes mellitus. Thus, Bjøro et al., Oslo and Verdal, Norway, analyzed 1972 persons with diabetes mellitus type I or II and found that hypothyroidism was present in females in type I DM, type II DM, and controls in, 10.3%, 8.1%, and 4.7% respectively, while these figures for males were 7.1%, 1.8%, and 0.8%. All these values are significantly higher as compared to controls for both sexes. A significantly increased prevalence of hyperthyroidism in both type I and type II diabetes was present in females: 3.7%, 3.5%, and 2.4% respectively, but for males only in type I DM: 2.9%, 0.7%, and 0.6% respectively. Belinchón et al., Canary Islands, Spain, detected thyroid autoimmunity in 14.9% of a group of 101 subjects (52 males) with type I DM, with or without clinical thyroid symptoms. The ratio female to male was 3 : 1 and thyroid autoimmunity was 4 times more frequent in subjects with islet cell antibodies versus absence of islet cell antibodies. Karlovich et al., Minsk, Belarus, measured TPO-Ab in 95 patients (46 males) with type I DM. In the total group, TPO-Ab were found in 34.7% of subjects, with a female to male ratio of 2 : 1. |
