title: Serum homocysteine levels are decreased in levothyroxine-treated women with autoimmune thyroiditis.
abstract: BACKGROUND
  Hyperhomocysteinemia is a well-known cardiovascular risk factor and its elevation is established in overt hypothyroidism. Since some authors suggest that chronic autoimmune thyroiditis per se may be considered as a novel risk factor of atherosclerosis independent of thyroid function, the analysis of classical cardiovascular risk factors might be helpful in evaluation the causative relationship. Data concerning the impact of thyroid autoimmunity in euthyroid state on homocysteine (Hcy) level is lacking. The aim of this study was to evaluate Hcy level in context of anti-thyroperoxidase antibodies (TPOAbs) in euthyroidism.
  
  
  METHODS
  It is a case-control study. 31 euthyroid women treated with levothyroxine (L-T4) due to Hashimoto thyroiditis (HT) and 26 females in euthyroidism without L-T4 replacement therapy were enrolled in the study. All women with HT had positive TPOAbs. Forty healthy females negative for TPOAbs comparable for age and body mass index (BMI) participated in the study as controls. Exclusion criteria were a history of any acute or chronic disease, use of any medications (including oral contraceptives and vitamin supplements), smoking, alcoholism.
  
  
  RESULTS
  TPOAbs titers were higher in both groups of HT patients versus the healthy controls. Hcy levels were found to be significantly lower in treated HT patients (Me 11 μmol; IQR 4.2 μmol) as compared with healthy controls (Me 13.35 μmol; IQR 6.34 μmol; p = 0.0179). In contrast, no significant difference was found between non treated HT and control group in Hcy level. The study groups and the controls did not differ in age and BMI. Furthermore, levels of TSH, FT4, TC, LDL, HDL and TAG did not differ between the study group and the control group.
  
  
  CONCLUSIONS
  The main finding of the study is a decrease in Hcy level in treated HT as compared with healthy controls. Based on our observations one can also assume that correct L-T4 replacement was associated here with a decrease of Hcy. Furthermore, it seems that non treated HT in euthyroidism is not associated with Hcy increase, in contrast to overt hypothyroidism. This may be just another argument against the concepts about the role of "euthyroid HT" in the development of atherosclerosis.
authors.affiliation: Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Przybyszewskiego St, 49, 60-355 Poznań, Poland. mowecki@ump.edu.pl.
authors.forename: Maciej
authors.initials: M
authors.lastname: Owecki
authors.forename: Jolanta
authors.initials: J
authors.lastname: Dorszewska
authors.forename: Nadia
authors.initials: N
authors.lastname: Sawicka-Gutaj
authors.forename: Anna
authors.initials: A
authors.lastname: Oczkowska
authors.forename: Michał K
authors.initials: MK
authors.lastname: Owecki
authors.forename: Michał
authors.initials: M
authors.lastname: Michalak
authors.forename: Jakub
authors.initials: J
authors.lastname: Fischbach
authors.forename: Wojciech
authors.initials: W
authors.lastname: Kozubski
authors.forename: Marek
authors.initials: M
authors.lastname: Ruchała