학술논문
Resting Energy Expenditure and Cold-induced Thermogenesis in Patients With Overt Hyperthyroidism
Clinical Research Article
Clinical Research Article
Document Type
Clinical report
Author
Source
Journal of Clinical Endocrinology & Metabolism. February 2022, Vol. 107 Issue 2, p450, 12 p.
Subject
Language
English
ISSN
0021-972X
Abstract
Hyperthyroidism is a common endocrine disease which, among other symptoms, often leads to weight loss and heat intolerance (1). Thyroid hormones (THs) are pivotal regulators of human energy expenditure (EE) [...]
Context: Thyroid hormone (TH) is crucial for the adaptation to cold. Objective: To evaluate the effect of hyperthyroidism on resting energy expenditure (REE), cold-induced thermogenesis (CIT) and changes in body composition and weight. Methods: This was a prospective cohort study at the endocrine outpatient clinic of a tertiary referral center. Eighteen patients with overt hyperthyroidism were included. We measured REE during hyperthyroidism, after restoring euthyroid TH levels and after 3 months of normal thyroid function. In 14 of the 18 patients, energy expenditure (EE) was measured before and after a mild cold exposure of 2 hours and CIT was the difference between EEcold and EEwarm. Skin temperatures at 8 positions were recorded during the study visits. Body composition was assessed by dual X-ray absorption. Results. Free thyroxine (fT4) and free triiodothyronine (fT3) decreased significantly over time (fT4, P = .0003; fT3, P = .0001). REE corrected for lean body mass (LBM) decreased from 42 [+ or -] 6.7 kcal/24 hour/kg LBM in the hyperthyroid to 33 [+ or -] 4.4 kcal/24 hour/kg LBM (-21%, P < .0001 vs hyperthyroid) in the euthyroid state and 3 months later to 33 [+ or -] 5.2 kcal/24 hour/kg LBM (-21%, P = .0022 vs hyperthyroid, overall P < .0001). fT4 (P = .0001) and fT3 (P < 0.0001) were predictors of REE. CIT did not change from the hyperthyroid to the euthyroid state (P = .96). Hyperthyroidism led to increased skin temperature at warm ambient conditions but did not alter core body temperature, nor skin temperature after cold exposure. Weight regain and body composition were not influenced by REE and CIT during the hyperthyroid state. Conclusion. CIT is not increased in patients with overt hyperthyroidism. Key Words. brown adipose tissue, hyperthyroidism, energy expenditure, cold induced thermogenesis, thyroid hormone
Context: Thyroid hormone (TH) is crucial for the adaptation to cold. Objective: To evaluate the effect of hyperthyroidism on resting energy expenditure (REE), cold-induced thermogenesis (CIT) and changes in body composition and weight. Methods: This was a prospective cohort study at the endocrine outpatient clinic of a tertiary referral center. Eighteen patients with overt hyperthyroidism were included. We measured REE during hyperthyroidism, after restoring euthyroid TH levels and after 3 months of normal thyroid function. In 14 of the 18 patients, energy expenditure (EE) was measured before and after a mild cold exposure of 2 hours and CIT was the difference between EEcold and EEwarm. Skin temperatures at 8 positions were recorded during the study visits. Body composition was assessed by dual X-ray absorption. Results. Free thyroxine (fT4) and free triiodothyronine (fT3) decreased significantly over time (fT4, P = .0003; fT3, P = .0001). REE corrected for lean body mass (LBM) decreased from 42 [+ or -] 6.7 kcal/24 hour/kg LBM in the hyperthyroid to 33 [+ or -] 4.4 kcal/24 hour/kg LBM (-21%, P < .0001 vs hyperthyroid) in the euthyroid state and 3 months later to 33 [+ or -] 5.2 kcal/24 hour/kg LBM (-21%, P = .0022 vs hyperthyroid, overall P < .0001). fT4 (P = .0001) and fT3 (P < 0.0001) were predictors of REE. CIT did not change from the hyperthyroid to the euthyroid state (P = .96). Hyperthyroidism led to increased skin temperature at warm ambient conditions but did not alter core body temperature, nor skin temperature after cold exposure. Weight regain and body composition were not influenced by REE and CIT during the hyperthyroid state. Conclusion. CIT is not increased in patients with overt hyperthyroidism. Key Words. brown adipose tissue, hyperthyroidism, energy expenditure, cold induced thermogenesis, thyroid hormone