Subclinical hyperthyroidism and blood pressure in a population-based prospective cohort study.
OBJECTIVE
There is current controversy on the association between subclinical hyperthyroidism and hypertension. Data from cohort studies have not been available yet. The present study was designed to longitudinally investigate possible associations of subclinical hyperthyroidism with blood pressure, pulse pressure and the risk of hypertension.


METHODS
We used data from the population-based, prospective cohort Study of Health in Pomerania and included 2910 subjects (1469 women) aged 20-79 years with completed 5-year examination follow-up. Subjects with increased serum TSH levels or overt hyperthyroidism were excluded. Serum TSH levels below 0.25 mIU/l with free triiodothyronine and free thyroxine levels within the reference range were defined as subclinical hyperthyroidism. Blood pressure was measured according to standard methods.


RESULTS
Multivariable analyses adjusted for age, sex, overweight, obesity, smoking status and time between the examinations did not reveal any statistically significant association between subclinical hyperthyroidism and any of the blood pressure-related variables in the whole study population. Although the 5-year hypertension incidence was higher in subjects with subclinical hyperthyroidism compared with those without (31.4 vs 19.2%; risk ratio 1.64; 95% confidence interval (CI) 1.17-2.28, P=0.006), both groups did not differ with respect to the risk of hypertension, after analyses were adjusted for confounders (relative risk 1.23, 95% CI 0.91-1.68, P=0.182). Analyses yielded similar results in subjects without thyroid disease and in those who took no antihypertensive medication.


CONCLUSIONS
Subclinical hyperthyroidism is not associated with changes in blood pressure, pulse pressure or incident hypertension.
Völzke
Henry
H
SHIP/Clinical-Epidemiological Research Unit, Institute of Community Medicine, Ernst Moritz Arndt University of Greifswald, Walther Rathenau Strasse 48, D-17487 Greifswald, Germany. voelzke@uni-greifswald.de
Ittermann
Till
T
Schmidt
Carsten O
CO
Dörr
Marcus
M
John
Ulrich
U
Wallaschofski
Henri
H
Stricker
Bruno H C
BH
Felix
Stephan B
SB
Rettig
Rainer
R
D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000503:physiopathology; D006980:Hyperthyroidism / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000503:physiopathology; D012959:Socioeconomic Factors; D055815:Young Adult
D000959:Antihypertensive Agents