Decreased serum TSH levels are not associated with mortality in the adult northeast German population
ABSTRACT Results of cohort studies on the association between decreased serum TSH levels and mortality are conflicting. Some studies demonstrated an increased mortality risk in subjects with decreased serum TSH levels, others did not. Even meta-analyses revealed contradictory results. We undertook the present study to investigate the association between decreased serum TSH levels and mortality in the large population-based Study of Health in Pomerania (SHIP).
Data from 3651 individuals from SHIP without known thyroid disorders or thyroid treatment were analyzed. Serum TSH, free triiodothyronine, and free thyroxine levels were determined by immunochemiluminescent procedures. Decreased TSH was defined as serum TSH levels below 0.25 mIU/l. Cox regression was used to associate decreased TSH levels with mortality.
The median duration of follow-up was 8.5 years (30 126 person years). During follow-up, 299 individuals (6.9%) died corresponding to a death rate of 9.92 deaths per 1000 person years. Survival time was shorter in subjects with decreased serum TSH levels compared to euthyroid individuals. After adjustment for age and sex, however, there was no association between decreased serum TSH levels and all-cause mortality (hazard ratio: 0.95; 95% confidence interval: 0.67; 1.36). Likewise, decreased serum TSH levels were neither associated with cardiovascular nor with cancer mortality.
There is no independent association of decreased serum TSH levels with all-cause, cardiovascular, and cancer mortality in the adult northeast German population. Although our study has some strengths, we cannot finally conclude on therapeutical implications in individuals with subclinical thyroid diseases.
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ABSTRACT: OBJECTIVE THE AIM OF THIS STUDY WAS TO INVESTIGATE THE INFLUENCE OF AGE ON THE ASSOCIATION BETWEEN THYROID FUNCTION AND MORTALITY.DESIGN THE NIJMEGEN BIOMEDICAL STUDY IS A POPULATION-BASED STUDY COMPRISING 5.816 RANDOMLY SELECTED ADULTS OF ALL AGE GROUPS WITHOUT PREVIOUSLY KNOWN THYROID DISEASE.METHODS THYROID STIMULATING HORMONE (TSH), FREE THYROXINE (FT4) AND PEROXIDASE ANTIBODIES WERE MEASURED IN 2002-2003. THE NUMBER OF DEATHS WERE ESTABLISHED IN 2012 (MEDIAN FOLLOW UP TIME 9.4 YEARS).RESULTS SUBCLINICAL THYROTOXICOSIS WAS ASSOCIATED WITH MORTALITY IN SUBJECTS 65 YEARS OLD (HR 2.5, 95% CI 1.1-5.7), BUT NOT IN SUBJECTS 65 YEARS OLD. in the 493 participants aged 80 years or older, a FT4 level in the high-normal range (18.5-22 pmol/l) was associated with a higher mortality in comparison to FT4 levels in the middle range (11.5-15.0 pmol/L): HR 1.7 (95% CI 1.0-2.9). In these elderly, also TSH levels within the high-normal range (3.0-4.0 mIU/L) were associated with a higher mortality in comparison to TSH levels within the middle range (1.0-2.0 mIU/L): HR 1.8 (95% CI 1.0-3.1).Conclusions The relationship between thyroid function and mortality differs according to age. This finding might (partially) explain the discrepant results of previous studies examining the relationship between thyroid function and mortality in different age groups.European Journal of Endocrinology 05/2014; DOI:10.1530/EJE-13-1070 · 3.69 Impact Factor
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ABSTRACT: Background Subclinical thyroid dysfunction may be a risk factor for mortality in patients with heart failure, and it may be associated with dilated cardiomyopathy (DCM). The present study is the cohort study to examine the possible association between subclinical thyroid dysfunction and all-cause mortality in DCM patients as the current evidence on this association remains elusive. Methods and Results A total of 963 DCM patients were evaluated for thyroid function. Of these patients, 7.1% (n=68) had subclinical hyperthyroidism (defined as serum TSH <0.35 μIU/mL), 84.7% (n=816) had euthyroidism (TSH 0.35-5.5 μIU/mL), and 8.2% (n=79) had subclinical hypothyroidism (TSH >5.5 μIU/mL). There was a significant difference in the all-cause mortality rate between patients with euthyroidism and patients with subclinical hyper- and hypothyroidism (21%, 38.2%, and 26.6%, respectively, log-rank χ2=13.104, P=0.001) with mean follow-up 3.5 years. After adjustment for other confounding factors at baseline, QRS duration, N-terminal fragment pro-brain natriuretic peptide, NYHA functional class, left atrium diameter and subclinical hyperthyroidism (HR 1.793, 95% CI 1.010-3.183, P=0.046) emerged as significant predictors of all-cause mortality. Conclusion Subclinical hyper- and hypothyroidism in DCM patients had higher all-cause mortality rate. However, only subclinical hyperthyroidism, not subclinical hypothyroidism, was an independent predictor for increased risk of all-cause mortality.Journal of Cardiac Failure 07/2014; 20(7). DOI:10.1016/j.cardfail.2014.05.002 · 3.07 Impact Factor
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ABSTRACT: Context: Subclinical hypothyroidism has been associated with increased risk of coronary heart disease (CHD), particularly with thyrotropin levels of 10.0 mIU/L or greater. The measurement of thyroid antibodies helps predict the progression to overt hypothyroidism, but it is unclear whether thyroid autoimmunity independently affects CHD risk. Objective: The objective of the study was to compare the CHD risk of subclinical hypothyroidism with and without thyroid peroxidase antibodies (TPOAbs). Data Sources and Study Selection: A MEDLINE and EMBASE search from 1950 to 2011 was conducted for prospective cohorts, reporting baseline thyroid function, antibodies, and CHD outcomes. Data Extraction: Individual data of 38 274 participants from six cohorts for CHD mortality, followed up for 460 333 person-years and 33 394 participants from four cohorts for CHD events. Data Synthesis: Among 38 274 adults (median age 55 y, 63% women), 1691 (4.4%) had subclinical hypothyroidism, of whom 775 (45.8%) had positive TPOAbs. During follow-up, 1436 participants died of CHD and 3285 had CHD events. Compared with euthyroid individuals, age- and gender-adjusted risks of CHD mortality in subclinical hypothyroidism were similar among individuals with and without TPOAbs [hazard ratio (HR) 1.15, 95% confidence interval (CI) 0.87-1.53 vs HR 1.26, CI 1.01-1.58, P for interaction 0.62], as were risks of CHD events (HR 1.16, CI 0.87-1.56 vs HR 1.26, CI 1.02-1.56, P for interaction = .65). Risks of CHD mortality and events increased with higher thyrotropin, but within each stratum, risks did not differ by TPOAb status. Conclusions: CHD risk associated with subclinical hypothyroidism did not differ by TPOAb status, suggesting that biomarkers of thyroid autoimmunity do not add independent prognostic information for CHD outcomes.Journal of Clinical Endocrinology & Metabolism 06/2014; 99(9):jc20141250. DOI:10.1210/jc.2014-1250 · 6.31 Impact Factor