Just how healthy were the subjects that any of them went on to develop metabolic syndrome?
Nonetheless, this is interesting in that it reinforces the importance of FT3 (even just as it relates to FT4 to produce the FT3:FT4 ratio) and reduces, again, the power of the TSH test.
Clin Endocrinol (Oxf). 2017 Apr 4. doi: 10.1111/cen.13345. [Epub ahead of print]
Free Triiodothyronine/Free Thyroxine Ratio rather than Thyrotropin is more associated with Metabolic Parameters in Healthy Euthyroid Adult Subjects.
Park SY1, Park SE2, Jung SW3, Jin HS4, Park IB3, Ahn SV5, Lee S3.
Author information
1 Department of Internal Medicine, Cheil General Hospital, Dankook University College of Medicine, Seoul, Korea.
2 Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
3 Department of Internal Medicine and Laboratory of Genomics and Translational Medicine, Gachon University School of Medicine, Incheon, Korea.
4 Department of Biomedical Laboratory Science, College of Life and Health Sciences, Hoseo University, Asan, Korea.
5 Department of Preventive Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
Abstract
OBJECTIVE:
The interrelation between TSH, thyroid hormones, and metabolic parameters is complex and has not been confirmed. This study aimed to determine the association of TSH and thyroid hormones in euthyroid subjects and the relationship between thyroid function and metabolic risk factors. Furthermore, this study examined whether thyroid function has predictive power for metabolic syndrome.
DESIGN:
This is a cross-sectional study that included subjects in a medical health check-up program at a single institution.
PATIENTS:
The study included 132,346 participants (66,991 men and 65,355 women) aged over 18 years who had TSH, free T4 (FT4), and free T3 (FT3) levels within the institutional reference ranges.
MEASUREMENTS:
TSH, FT4, FT3, and metabolic parameters including height, weight, waist circumference, blood pressure, serum levels of total cholesterol, triglyceride, high-density lipoprotein cholesterol, insulin, and glucose were measured.
RESULTS:
There was a positive association between FT3/FT4 ratio and TSH in both men and women after adjusting for age, body mass index, smoking status, and menopausal status (in women). The FT3/FT4 ratio and TSH were positively associated with risk of metabolic syndrome parameters including insulin resistance. The FT3/FT4 ratio had a greater predictive power than TSH for metabolic syndrome in both men and women.
CONCLUSIONS:
TSH levels were positively associated with FT3/FT4 ratio within the euthyroid range. The higher FT3/FT4 ratio is associated with increased risk of metabolic syndrome parameters and insulin resistance. FT3/FT4 ratio has a better predictive power for metabolic syndrome than TSH. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
KEYWORDS:
TSH ; FT3/FT4 Ratio; Metabolic syndrome; Thyroid hormone
PMID: 28374508
DOI: 10.1111/cen.13345
Amiodarone and Thyroid query
