Increases in Thyrotropin Within the Near-Normal Range Are Associated With Increased Triiodothyronine But Not Increased Thyroxine in the Pediatric Age Group

Karavani, Gilad; Strich, David; Edri, Shalom; Gillis, David

doi:10.1210/jc.2014-1441

Cited by 30 publications

(43 citation statements)

References 17 publications

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“…A retrospective analysis of a large community-based pediatric clinic population in Jerusalem, which included some subjects with subclinical hypothyroidism, found positive correlations between BMI and TSH, fT3, and fT3:fT4 ratios. Conversely, fT4 demonstrated a negative relation with BMI (27). Although the relations between thyroid hormones and BMI were significant only in children with obesity, higher TSH correlated with higher fT3 (but not fT4) levels, even in healthy-weight children (27).…”

Section: Discussionmentioning

confidence: 82%

“…Conversely, fT4 demonstrated a negative relation with BMI (27). Although the relations between thyroid hormones and BMI were significant only in children with obesity, higher TSH correlated with higher fT3 (but not fT4) levels, even in healthy-weight children (27). A retrospective review of U.S. children and adolescents confirmed an association with higher TSH values at or slightly above the normal reference range with obesity; the free thyroid hormone data were not sufficient for analysis (34).…”

Section: Discussionmentioning

confidence: 87%

“…In most of the retrospective series that have examined the relations between TSH, thyroid hormones, and body composition, the sampling of thyroid tests was performed for clinical reasons. Hence, a confounder effect cannot be ruled out (25,27,29). The present assessment of an unselected U.S. population (by default devoid of specific clinical indications for testing) minimizes the risk of selection bias.…”

Section: Discussionmentioning

confidence: 99%

“…In a retrospective chart review of children aged 2-18 years, TSH was positively correlated with BMI, triglyceride levels, fasting insulin, and insulin resistance, as estimated by the homeostatic model assessment for insulin resistance (HOMA-IR), while fT4 was negatively correlated with triglycerides (25). In addition to a positive linear association between serum TSH levels and BMI (26), TSH and fT3 have been found to be significantly higher in children and adolescents with obesity compared with healthy weight youth, without an increase in fT4 (27). TSH has been found to be positively associated not only with blood pressure (28), but also with total cholesterol (TC), lowdensity lipoprotein cholesterol (LDL-C), and triglycerides in a population-based study of German children and adolescents, with the strongest relationship between a higher-risk lipid profile and TSH found in children who were overweight and obese (29).…”

Section: Introductionmentioning

confidence: 90%

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Thyrotropin Levels Are Associated with Cardiometabolic Risk Factors in Euthyroid Adolescents

2016

Thyroid

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Background: Increased thyrotropin (TSH) levels and free triiodothyronine to free thyroxine (fT3:fT4) ratios, even within the euthyroid range, have been associated with cardiometabolic risk factors in adults but are less characterized in youth. This study sought to determine relations between TSH, thyroid hormones, and cardiometabolic risk factors in euthyroid adolescents. Methods: Data were extracted from the United States National Health and Nutrition Examination Survey, 2007-2010, for univariate and multivariate analyses of TSH, thyroid hormones, body mass index (BMI), blood pressure, lipids, and glucose metabolism. Subjects aged 12-18 years, with normal TSH and antithyroid peroxidase antibody levels, and without a history of thyroid disease, diabetes, or treatment of hypertension/dyslipidemia (n = 1167) were included. TSH and thyroid hormones were assessed for impact on BMI Z-score, systolic blood pressure (SBP) diastolic blood pressure, total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, triglycerides, and glucose metabolism. Results: Univariate analyses revealed positive linear relations between TSH and SBP, TC, fasting and two-hour glucose, and homeostasis model assessment of insulin resistance (HOMA-IR). The fT3:fT4 ratio negatively correlated with high-density lipoprotein cholesterol but positively with BMI Z-score, SBP, triglycerides, fasting and two-hour glucose, fasting insulin, and HOMA-IR. In multivariate analyses controlling for age, sex, race/ ethnicity, and BMI Z-score, relations between TSH and both TC and fasting glucose remained significant, and the fT3:fT4 ratio was positively associated with fasting glucose and HOMA-IR. Conclusions:In an unselected population of euthyroid U.S. adolescents, TSH and thyroid hormones correlate with multiple cardiometabolic risk factors, with age-and sex-independent effects on cholesterol and glucose metabolism.

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 90%

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Thyrotropin Levels Are Associated with Cardiometabolic Risk Factors in Euthyroid Adolescents

2016

Thyroid

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“…In children, we recently reported that within the normal range, the free triiodothyronine (FT3)/free thyroxine (FT4) ratio increases as thyroid-stimulating hormone (TSH) levels increase (1). This effect may be caused by increased deiodination of thyroxine (T4) to triiodothyronine (T3) that has been shown to occur in the cells of the thyroid gland in vitro in response to TSH (2,3).…”

Section: Introductionmentioning

confidence: 99%

TSH enhancement of FT4 to FT3 conversion is age dependent

Strich

Karavani

Edri

et al. 2016

European Journal of Endocrinology

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Objective: We previously reported increasing free T3 (FT3) to free T4 (FT4) ratios as thyroid-stimulating hormone (TSH) increases within the normal range in children. It is not known if this phenomenon is age-related among humans, as previously reported in rats. This study examines the relationships between TSH and FT3/FT4 ratios in different ages. Design: Retrospective examination of thyroid tests from patients without thyroid disease from community clinics. Methods: Free T3, free T4, and TSH levels from 527 564 sera collected from patients aged 1 year or greater were studied. Exclusion criteria were the following: missing data, TSH greater than 7.5 mIU/L, and medications that may interfere with thyroid hormone activity. A total of 27 940 samples remaining after exclusion were stratified by age. Samples with available anthropometric data were additionally stratified for body mass index (BMI). Correlations of TSH to FT4, FT3, and FT3/FT4 ratios by age group were examined. Results: Up to age 40, for each increasing TSH quartile, FT3 and the FT3/FT4 ratio increased and FT4 decreased significantly (for both FT3, FT4 and FT3/FT4 ratio, P < 0.05 for every TSH quartile when compared with the 1st quartile, except FT3 in the 30-40 age group). In older age groups, increasing TSH was not associated with increased FT3/FT4 ratio. Conclusion: As TSH levels increase, FT3/FT4 ratios increase until age 40, but this differential increase does not occur in older age groups. This may reflect a decrease in thyroxine (T4) to triiodothyronine (T3) conversion with age, which may be part of the aging process.

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The effects of obesity on the human body part III: Cardiovascular, digestive, excretory, endocrine, and reproductive

et al. 2020

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This third installment of The Effects of Obesity on the Human Body discusses the endocrine, digestive, reproductive, cardiovascular, and excretory systems. Obesity is known to upset hormonal balance, leading to widespread metabolic disorders involving organs such as the liver and pancreas. Furthermore, the hypersecretion of leptin from adipose tissue triggers various responses from the cardiovascular and gastrointestinal systems, with implications for energy and nutrient balance and uptake.

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Increases in Thyrotropin Within the Near-Normal Range Are Associated With Increased Triiodothyronine But Not Increased Thyroxine in the Pediatric Age Group

Abstract: Within the near-euthyroid range, increasing TSH levels are associated with increasing FT3 levels, without an increase in FT4. This provides in vivo support for TSH enhancing preferentially T3 production and/or secretion.

Cited by 30 publications

References 17 publications

Thyrotropin Levels Are Associated with Cardiometabolic Risk Factors in Euthyroid Adolescents

Thyrotropin Levels Are Associated with Cardiometabolic Risk Factors in Euthyroid Adolescents

TSH enhancement of FT4 to FT3 conversion is age dependent

The effects of obesity on the human body part III: Cardiovascular, digestive, excretory, endocrine, and reproductive

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