Decreased serum TSH levels are not associated with mortality in the adult northeast German population

Institute for Community Medicine, Ernst Moritz Arndt University, University of Greifswald, Walther Rathenau Strasse 48, D-17487 Greifswald, Germany.
European Journal of Endocrinology (Impact Factor: 3.69). 12/2009; 162(3):579-85. DOI: 10.1530/EJE-09-0566
Source: PubMed

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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Bei der Hashimoto-Thyreoiditis handelt es sich um eine häufige Autoimmunerkrankung der Schilddrüse, die das weibliche Geschlecht bevorzugt. Pathognomonisch für die chronische lymphozytäre Thyreoiditis sind Autoantikörper gegen die Schilddrüsenperoxidase sowie gegen Thyreoglobulin. Laborchemisch liegt bei Diagnosestellung häufig eine latente Hypothyreose vor, die sich infolge der lymphozytären Infiltration der Schilddrüse zu einer substitutionsbedürftigen Hypothyreose mit klassischer klinischer Symptomatik ausbilden kann. Sonographisch zeigt sich die Schilddrüse typischerweise inhomogen und echoarm. Es besteht eine hohe Koinzidenz mit anderen Autoimmunerkrankungen, z.B. Vitiligo, Morbus Addison, Diabetes mellitus Typ 1, z.T. auch als polyglanduläres Syndrom 2. Hashimoto’s thyroiditis is a common autoimmune thyroid disease with preference of female gender. The chronic thyroiditis is characterized by autoantibodies against thyroid peroxidase and thyroglobulin. With manifestation, there is often a subclinical hypothyroidism that finally progresses to a persistent hypothyroidism with typical clinical symptoms and the need of hormonal substitution in succession of the lymphocytic infiltration of the thyroid. The ultrasound of the thyroid shows a hypoechogenic and inhomogeneous parenchyma. Autoimmune thyroiditis is frequently associated with autoimmune disease of other organs, such as vitiligo, Addison’s disease, diabetes mellitus type 1, often in the sense of polyglandular syndrome 2. Schlüsselwörter: TPO-AK-Hypothyreose-Polyglanduläres Syndrom 2 Key Words: TPO-AB-Hypothyroidism-Polyglandular syndrome 2
    07/2010; 105(7):485-493. DOI:10.1007/s00063-010-1082-y
  • [Show abstract] [Hide abstract]
    ABSTRACT: The association of endogenous subclinical hyperthyroidism (SHyper) with cardiovascular mortality is controversial. This may reflect the different causes of endogenous SHyper in the population studied due to differences in iodine intake, and different selection criteria, e.g. sex, age, and race, the cutoff for serum TSH level, the duration of follow-up, and the presence of co-morbidities. A small sample size of SHyper patients could have caused a low statistical power in some of these studies. In other studies, the results were not adjusted for relevant confounders. Importantly, various meta-analyses have also given conflicting results. This issue of the European Journal of Endocrinology contains two articles that address the association between endogenous SHyper and cardiovascular and total mortality: one study was conducted in a north-eastern German population and the other in a Japanese-Brazilian population. After adjusting for relevant confounders, there was no association between decreased serum TSH levels and all-cause and cardiovascular mortality in the Pomerania study; on the contrary, all-cause mortality and cardiovascular mortality were significantly higher for individuals with SHyper in the Japanese-Brazilian population. Interestingly, both studies had similar characteristics in terms of selection criteria and duration of follow-up. It remains controversial whether or not to treat middle-aged patients with low serum TSH levels. Large prospective randomized controlled double-blind studies of young and middle-aged patients with SHyper and without underlying cardiac disease are required to assess the potential benefits of treating endogenous SHyper in these age groups.
    European Journal of Endocrinology 03/2010; 162(3):587-9. DOI:10.1530/EJE-09-1095 · 3.69 Impact Factor
  • The Journals of Gerontology Series A Biological Sciences and Medical Sciences 05/2010; 65(11):1250-1; author reply 1252-3. DOI:10.1093/gerona/glq076 · 4.98 Impact Factor
Show more