Five-year change in morphological and functional alterations of the thyroid gland: the Study of Health in Pomerania.
BACKGROUND
While cross-sectional data on thyroid epidemiology are common, few longitudinal data on the incidence and progression of thyroid disorders exist. The aim of this study was to analyze the 5-year change and the incidence of morphological and functional alterations of the thyroid gland in a previously iodine-deficient area.


METHODS
We used 5-year follow-up data based on 2941 participants (20-79 years) of the population-based Study of Health in Pomerania. The thyroid structure and size were measured by ultrasonography. Thyroid function and serum autoantibodies to thyroperoxidase (anti-TPO-Ab) were evaluated.


RESULTS
During follow-up, the median iodine/creatinine ratio decreased slightly from 134.2 to 130.4 μg/g. The mean thyroid volume was nonsignificantly increased by 0.73 mL [confidence interval (CI) -1.68-3.41 mL]. The incidence rate of goiter was 34.0 [CI 30.7-37.7] per 1000 person-years (py), the incident rate of nodules was 16.6 [CI 14.5-19.1] per 1000 py. Median serum thyrotropin levels increased slightly (0.10 [CI -0.10-0.34 mIU/L]). The incidence of positive anti-TPO-Ab was 3.4 [CI 2.6-4.7] per 1000 py. For all thyroid parameters, the regression rates were higher than the incidence rates.


CONCLUSIONS
After iodine fortification became effective in this previously iodine-deficient region, there is a negative net balance between occurring and reverting goiter and nodules. Along with balanced incidences of hyper- and hypothyroid dysfunction and the low incidence of autoimmune-related findings, these findings indicate that the current iodine status is sufficient to prevent iodine deficiency-related disorders in the adult population of the study region.
Institute for Community Medicine, Ernst Moritz Arndt University Greifswald, Greifswald, Germany. voelzke@uni-greifswald.de
Henry
H
Völzke
Till
T
Ittermann
Martin
M
Albers
Nele
N
Friedrich
Matthias
M
Nauck
Harald
H
Below
Axel
A
Kramer
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D015331:Cohort Studies; D003677:Deficiency Diseases / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006042:Goiter / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007453:Iodide Peroxidase / Q000276:immunology*; D007455:Iodine / Q000172:deficiency* / Q000652:urine; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D013959:Thyroid Diseases / Q000097:blood / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000473:pathology*; D016606:Thyroid Nodule / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014463:Ultrasonography
D001323:Autoantibodies; D013972:Thyrotropin; D007455:Iodine; D007453:Iodide Peroxidase; D013974:Thyroxine