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Abstract
Subclinical thyroid dysfunction is defined by serum thyroid-stimulating hormone (TSH) levels either greater or less than the reference range with normal thyroxine (T4) concentrations, and consists of subclinical hypothyroidism (SCH) and subclinical hyperthyroidism (SCHyper). For the proper diagnosis of SCH, it is most important to be able to correctly evaluate the serum TSH levels, which have numerous unique characteristics. We also need to be versed in TSH harmonization, which was recently launched world-wide. In this review, we will attempt to determine the best clinical approaches to the treatment of subclinical thyroid dysfunction based on recent guidelines published from several countries and novel findings of several recent large-scale clinical studies.
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Affiliation(s)
- Koshi Hashimoto
- Department of Diabetes, Endocrinology, and Hematology, Dokkyo Medical University Saitama Medical Center, Saitama 343-8555, Japan
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Shimizu Y, Kawashiri SY, Noguchi Y, Nakamichi S, Nagata Y, Hayashida N, Maeda T. Associations among Ratio of Free Triiodothyronine to Free Thyroxine, Chronic Kidney Disease, and Subclinical Hypothyroidism. J Clin Med 2022; 11:jcm11051269. [PMID: 35268361 PMCID: PMC8911058 DOI: 10.3390/jcm11051269] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/19/2022] [Accepted: 02/22/2022] [Indexed: 02/05/2023] Open
Abstract
The ratio of free triiodothyronine (FT3) to free thyroxine (FT4) (FT3/FT4), a maker of peripheral thyroxin deiodination, could indicate activity of thyroid hormone. Since positive association between subclinical hypothyroidism (SCH) and chronic kidney disease (CKD) was reported, clarifying the association among FT3/FT4, SCH, and CKD could be an efficient tool to make a strategy for preventing CKD. A cross-sectional study with 1724 Japanese with normal thyroid hormone was conducted. Significant positive association between SCH and CKD was observed; the adjusted odds ratio (OR) and 95% confidence interval (95% CI) was 2.23 (1.38, 3.59). Even though, FT3/FT4 was found to be inversely associated with CKD whereas positively associated with SCH; the adjusted ORs and 95% CIs for 1 standard deviation (SD) increment of FT3/FT4 were 0.51 (0.35, 0.74) for CKD and 2.40 (1.34, 4.29) for SCH, respectively. FT3/FT4 was also found to be positively associated with SCH without CKD but not those with CKD; 1 SD increment of FT3/FT4 were 3.44 (1.72, 6.91) for SCH without CKD and 1.11 (0.40, 3.06) for SCH with CKD, respectively. Although further investigation is necessary, present study indicates that higher activity of peripheral thyroxin deiodination might have beneficial association on absence of CKD even among SCH which is positively associated with CKD.
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Affiliation(s)
- Yuji Shimizu
- Department of General Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8501, Japan;
- Department of Cardiovascular Disease Prevention, Osaka Center for Cancer and Cardiovascular Diseases Prevention, Osaka 537-8511, Japan
- Correspondence: ; Tel.: +81-95-819-7578
| | - Shin-Ya Kawashiri
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan; (S.-Y.K.); (Y.N.); (Y.N.)
- Leading Medical Research Core Unit, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan;
| | - Yuko Noguchi
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan; (S.-Y.K.); (Y.N.); (Y.N.)
| | - Seiko Nakamichi
- Nagasaki University Health Center, Nagasaki 852-8523, Japan;
| | - Yasuhiro Nagata
- Department of Community Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan; (S.-Y.K.); (Y.N.); (Y.N.)
- Leading Medical Research Core Unit, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan;
| | - Naomi Hayashida
- Leading Medical Research Core Unit, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan;
- Division of Promotion of Collaborative Research on Radiation and Environmental Health Effects, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki 852-8523, Japan
| | - Takahiro Maeda
- Department of General Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8501, Japan;
- Leading Medical Research Core Unit, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan;
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