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Different levels of thyroid hormones between impaired fasting glucose and impaired glucose tolerance: free T3 affects the prevalence of impaired fasting glucose and impaired glucose tolerance in opposite ways
Author(s) -
Jing Su,
Xiaoying Ding,
Ying Xu,
Rui Liu,
Mingyu Gu,
Yuting Chen,
Yanhua Yin,
Yufan Wang,
Haiyan Sun,
Yongde Peng
Publication year - 2014
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.12384
Subject(s) - medicine , impaired glucose tolerance , impaired fasting glucose , endocrinology , prediabetes , euthyroid , diabetes mellitus , glucose tolerance test , thyroid , postprandial , blood sugar regulation , type 2 diabetes , insulin resistance
Context There is an association between thyroid disorders and diabetes mellitus. Objective To investigate thyroid hormone levels in different glucose metabolic statuses, analyse relationships between thyroid hormone levels and different categories of prediabetes and metabolic parameters within a large euthyroid nondiabetic population. Methods A total of 3328 subjects without diabetes or thyroid dysfunction were included in this cross‐sectional study. Subjects were divided in to four groups [normal glucose tolerance ( NGR ), impaired fasting glucose ( IFG ), impaired glucose tolerance ( IGT ) and combined glucose intolerance ( CGI )] according to the results of oral glucose tolerance test. Participants were then divided into four groups according to the quartile of free T3 ( FT 3) in their blood. Results Subjects with IFG had higher levels of FT 3 and ratio of FT 3 to FT 4 ( FT 3/ FT 4), but lower level of free T4 ( FT 4) than subjects with IGT . FT 3/ FT 4 was negatively associated with postprandial plasma glucose ( PPG ) [standardized β (β) = −0·087; P < 0·001]. The prevalence of IFG and CGI was increased with the level of FT 3, while the prevalence of IGT was decreased with the level of FT 3 ( P for trend: <0·001, 0·003 and <0·001, respectively). FT 3 was negatively associated with the risk of IGT ( OR = 0·409, 95% CI 0·179–0·935), whereas FT 4 was positively associated with the risk of IGT ( OR = 1·296, 95% CI 1·004–1·673). Conclusions Free thyroid hormone levels were different between subjects with IFG and IGT . FT 3 affects the prevalence of IFG and IGT in opposite ways. The difference in thyroid hormone levels may play an important role in the different pathological mechanisms of IFG and IGT .