Session: MON 437-470-Non-neoplastic Thyroid Disorders
Poster Board MON-459
Methods. We studied N. 795 euthyroid elderly subjects, ( 345 M, 450 F) who participated in the InCHIANTI Study, a population-based study of community-dwelling individuals, aged 75 ±7.3 (M ±SD) years. Euthyroidism was defined based on normal plasma TSH levels. Also, plasma free thyroxine (FT4) and free triiodothyronine (FT3) as well as serum Vit B12 levels were measured. All hormonal evaluations were performed by immunochemiluminescence. Vit B12 levels were measured by Radioimmunoassay with normal reference range of 200 to 920 pmol/L . Logistic regression analysis was used to examine the cross-sectional association between FT3, FT4,TSH and circulating levels of Vit B12 after adjusting for age, sex and multiple potential confounders such as, selenium, interleukin-6, transaminase, BMI, smoke, chronic heart failure, calory intake.
Results. All hormonal levels were within the normal reference range. Plasma concentrations of FT3, FT4, and TSH were 4.23±0.45 pg mL, 1.45 ±0.29 ng/dL, and 1.53±0.84 mIU/L, respectively. Circulating concentrations of Vit B12 were 344.02 ±264.16 pmol/L. The regression analysis demonstrated that FT4 levels were significantly associated with Vit B12 levels both in the analysis adjusted for age and sex, ( beta coefficient, 0.0000817795; SE,0.00003852; P=0.0341) and the fully adjusted analysis (beta coefficient, 0.0001169418; SE, 0.00004251; P=0.0061). Neither FT3 nor TSH levels were associated with Vit B12 levels. Of interest, the association between FT4 and Vit B12 was significant even when subjects with Vit B12 levels below the reference range were removed from analyses.
Conclusions. In euthyroid elderly subjects, circulating Vit B12 is associated with FT4. This phenomenon might be related to a positive effect of Vit B12 on thyroid hormone synthesis.
Nothing to Disclose: GC, FL, EU, MM, MM, SB, GC, LF
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