The prevalence of hypothyroidism in women of childbearing age is relatively high. The incidence of hypothyroidism during pregnancy has been calculated as between 0.3% and 0.7%. Overt abnormalities in thyroid function are common endocrine disorders affecting more than 19.2% of pregnant women in certain geographic areas of Hungary. 80% of Hungarian inhabitants are living in an iodine deficient area. The aim of this study was to investigate the prevalence of thyroid dysfunction in Hungarian Vizsla, a traditional breeding dog population.
A screening study was done on 95 Hungarian Vizsla, females and males. Serum total thyroxin, free thyroxin, triiodotyronine, total cholesterol and triglyceride concentrations were measured. The owners were asked to fill in a questionnaire concerning feeding and reproductive problems. TT4, freeT4 and T3 concentrations were determined by ELISA validated for use in canine serum.
The means and standard errors of the data were calculated and subjected to ANOVA and Students t-test where appropriate. Significance was set at P≤0.05.
Total T4 concentration of 36 dogs was lower (15.72±2.62 (mean±S.D.)) than the reference range (20.045.0 nmol/l). Total T4 level of 56 dogs was in reference range 26.83±4.68 and of five was higher, 92.97±64.86, than range. Total T4, free T4 and K values were different in the three groups at level of significance. T3 concentrations of suspected hypothyroid dogs (0.66±0.24), dogs with normal thyroid function (0.77±0.45) and dogs with suspected hyperthyroidism (0.67±0.06) were not different at level of significance. TT4 concentrations of 25 (26.3%) dogs with familiar relations were out of reference range.
Our approach of a clinical investigation-based screening was rather efficient in suspicion of overt thyroid dysfunction but not for detecting many cases with subclinical dysfunction. The high incidence of TT4 values out of range indicates a suspicion that the effect of iodine deficiency on thyroid function of dogs is similar to that in human subjects.