title: Higher serum free triiodothyronine levels within the normal range are associated with metabolic syndrome components in type 2 diabetic subjects with euthyroidism.
abstract: Associations of thyroid hormones with visceral obesity and insulin resistance in obese subjects with euthyroidism have been reported. However, there are no such reports in subjects with type 2 diabetes. The purpose of our study is to observe a relationship between thyroid hormones and components of metabolic syndrome (MetS) in type 2 diabetic subjects with euthyroidism defined by normal thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels. Subjects were 301 Japanese patients with type 2 diabetes. Serum TSH, FT4, free triiodothyronine (FT3), and variables related to MetS were measured. MetS was defined by the Japanese criteria and the criteria of the National Cholesterol Education Program modified for Asians. We found that serum FT3 levels were significantly and positively associated with BMI, visceral fat area, systolic and diastolic blood pressure, estimated glomerular filtration rate, serum triglyceride, and urine C peptide as a marker of insulin production, whereas negatively with age and HbA1c. In contrast, fewer numbers of variables were associated with serum TSH and FT4 levels. By a multiple regression analysis, FT3 level was independently associated with components of MetS such as visceral fat area, systolic blood pressure, and fasting blood glucose levels. On the other hand, the presence of these MetS components was independently associated with FT3 levels and urine C peptide. In conclusion, these results suggest a significant relationship between serum FT3 levels and components of MetS in type 2 diabetic subjects with euthyroidism, and imply a role of FT3 in MetS in type 2 diabetes.
authors.affiliation: Division of Diabetes and Metabolism, Department of Internal Medicine, Iwate Medical University School of Medicine.
authors.forename: Haruhito
authors.initials: H
authors.lastname: Taneichi
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Sasai
authors.forename: Mio
authors.initials: M
authors.lastname: Ohara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Honma
authors.forename: Kan
authors.initials: K
authors.lastname: Nagasawa
authors.forename: Toru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Ishii
authors.forename: Fumikado
authors.initials: F
authors.lastname: Fujiwara
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yamashina
authors.forename: Takashi
authors.initials: T
authors.lastname: Kajiwara
authors.forename: Noriko
authors.initials: N
authors.lastname: Takabe
authors.forename: Kazuma
authors.initials: K
authors.lastname: Takahashi
authors.forename: Jo
authors.initials: J
authors.lastname: Satoh
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications*; D005260:Female; D006801:Humans; D000960:Hypolipidemic Agents / Q000627:therapeutic use; D016015:Logistic Models; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000150:complications*; D008875:Middle Aged; D012016:Reference Values; D013959:Thyroid Diseases / Q000097:blood* / Q000150:complications*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D000959:Antihypertensive Agents; D000960:Hypolipidemic Agents; D014284:Triiodothyronine