Changes in Body Compositions and Basal Metabolic Rates during Treatment of Graves' Disease

Exploring Post-treatment Weight Changes in Overweight and Obese Patients With Graves' Disease: A Retrospective Analysis

INTRODUCTION

Graves' disease (GD) is associated with primary hyperthyroidism, leading to weight loss before treatment. During the treatment, weight gain is frequently observed, often surpassing the initial weight loss. This study aimed to analyze weight fluctuations in GD patients, focusing on the subset of overweight and obese (OAO) individuals, considering the significant metabolic implications and heightened cardiovascular risk of these weight changes.

METHODS

A retrospective cohort study included 122 GD patients with biochemical primary hyperthyroidism and at least 12 months of clinical follow-up after treatment for analysis. The OAO cohort comprised individuals with a body mass index (BMI) ≥25 kg/m². Data on laboratory, demographic, and weight variables were collected longitudinally.

RESULTS

During the hyperthyroidism state, 34.4% (n=42) of patients presented with weight loss, a phenomenon linked to lower serum thyroid-stimulating hormone levels at diagnosis (p=0.010) and an extended need for anti-thyroid drug treatment (p<0.001). Following treatment, around 60% (n=73) of individuals encountered weight gain, exhibiting a higher prevalence among women (p<0.001) and those undergoing definitive treatment modalities (p=0.024). Notably, 26.2% (n=32) experienced excessive weight gain, which was correlated with higher premorbid BMI and diminished weight loss induced by hyperthyroidism (p<0.001). Within the OAO cohort, 66.7% (n=26) observed an increase in weight post-treatment, and in 28.2% (n=11), excessive weight gain was reported. Weight gain and excessive weight gain were noted in patients with higher initial BMIs.

CONCLUSIONS

This study highlights that post-treatment weight gain is common, emphasizing the need for careful weight management in GD. In OAO GD patients, the association between initial BMI and increased weight underscores potential cardiovascular risks, warranting vigilant monitoring and early intervention.

Effects of levothyroxine substitution therapy on hunger and food intake in individuals with hypothyroidism

Context

In individuals with hypothyroidism and overweight, levothyroxine substitution therapy is often expected to cause weight loss due to its effect on resting energy expenditure. However, despite levothyroxine-induced enhancement of resting energy expenditure, fat mass loss is rarely seen after levothyroxine substitution therapy. The mechanism behind this conundrum is unknown.

Aim

The aim of the study was to assess the effect of levothyroxine therapy on hunger sensations and ad libitum food intake in individuals with hypothyroidism.

Design and setting

Prospective cohort study of 18 newly diagnosed hypothyroid women (thyroid-stimulating hormone (TSH) >10 mU/L). Participants were investigated at diagnosis, after normalization of TSH (<4.0 mU/L), and after 6 months of successful treatment. Eighteen age and body mass index-matched healthy controls were also included.

Intervention

Hypothyroid individuals were treated with levothyroxine according to European Thyroid Association guidelines.

Main outcomes

Changes in hunger sensation were assessed using visual analog scales (cm) before and during a standardized mixed meal test, and food intake was measured during a subsequent ad libitum meal (g).

Results

After 6 months of levothyroxine therapy, mean resting energy expenditure was increased by 144 kcal/day (10%) (P < 0.001). Weight loss was comprised of 0.8 kg fat-free mass while fat mass remained unchanged. Fasting hunger sensation increased from a mean of 4.5 (s.d. 2.2) cm to 5.5 (s.d. 2.2) cm (P = 0.047). The numerical increase in ad libitum meal intake did not reach statistical significance.

Conclusion

Our data suggest that levothyroxine-induced hunger may be a culprit in the lack of fat mass loss from levothyroxine therapy.

THYROTOXICOSIS AND ITS RELATION TO SARCOPENIA, MUSCLE STRENGTH, MUSCLE MASS AND PHYSICAL PERFORMANCE

Background

Sarcopenia is a syndrome, considered one of the main risk factors for morbidity and mortality among adults. Thyrotoxicosis may contribute to its development.

Aim

To assess the physical well-being among women with thyrotoxicosis and to determine the risk of sarcopenia among them; 13 women over 40 years of age with thyrotoxicosis took part in this study.

Materials and Methods

Grip strength was used to assess muscle strength. Appendicular skeletal muscle mass, adjusted for body size was used to asses muscle quantity. Physical performance was measured by gait speed test. We divided women in groups: group A - patients with newly diagnosed thyrotoxicosis and group B - patients who had started treatment.

Results

The values of muscle strength, muscle mass and gait speed were lower in group A compared to group B. Three of the patients in group A were diagnosed with severe sarcopenia. Thus the frequency of sarcopenia was 50% in this group. None of the women in group B met the criteria for sarcopenia.Despite the small number of women in this study, we can conclude that untreated thyrotoxicosis is a risk factor for decreased muscle strength, quantity and physical performance and could cause secondary sarcopenia.

Levothyroxine therapy, calculated deiodinases activity and basal metabolic rate in obese or nonobese patients after total thyroidectomy for differentiated thyroid cancer, results of a retrospective observational study

INTRODUCTION

Therapy for hypothyroid obese patients is still under definition since the thyrotropin-stimulating hormone (TSH) level is a less reliable marker of euthyroidism than nonobese patients. Indeed, TSH levels positively correlate with body mass index (BMI), and this increase may be a compensatory mechanism aimed at increasing energy expenditure in obese people. In contrast, the correlation of BMI with thyroid hormone levels is not completely clear, and conflicting results have been obtained by several studies. The L-T4 replacement dose is more variable in obese hypothyroid patients than in nonobese patients, and a recent study indicated that the L-T4 replacement dose is related to lean body mass in obese thyroidectomized patients. We aimed to study the correlations of L-T4-administered dose, thyroid hormone levels and TSH secretion with basal metabolic rate (BMR) and total calculated deiodinase activity (GD) in obese and nonobese athyreotic patients. We also looked for individualized L-T4 replacement dose set points to be used in clinical practice.

METHODS

We studied retrospectively 160 athyreotic patients, 120 nonobese and 40 obese. GD was calculated by SPINA Thyr 4.2, the responsiveness of the hypothalamic/pituitary thyrotrope by Jostel's thyrotropin (TSH) index and BMR by the Mifflin-St. Jeor formula, the interplay of GD and BMR with L-T4, thyroid hormones and TSH index (TSHI) was also evaluated.

RESULTS

In our study, the L-T4 dose was an independent predictor of GD, and approximately 30% of athyreotic patients under L-T4 therapy had a reduced GD; FT4 levels were higher and negatively modulated by BMR in obese athyreotic patients respect to nonobese, in these patients a T4 to T3 shunt, in terms of TSHI suppression is observed suggesting a defective hypothalamic pituitary T4 to T3 conversion and a resistance to L-T4 replacement therapy.

CONCLUSIONS

L-t4 dose is the most important predictor of GD, BMR modulates T4 levels in obese athyreotic patients that are resistant to L-T4 replacement therapy.

Brown adipose tissues mediate the metabolism of branched chain amino acids during the transitioning from hyperthyroidism to euthyroidism (TRIBUTE)

Both hyperthyroidism and elevated plasma branched chain amino acids (BCAA) are associated with insulin resistance. BCAA utilization and clearance relative to thyroid status changes remains unclear. We investigate amino acids changes, specifically BCAA, during the transition from hyperthyroidism to euthyroidism, and the impact of active brown adipose tissue (BAT) on the metabolic effects of BCAA. Newly diagnosed Graves’ disease participants were recruited. Hyperthyroidism was treated via a titration dosing regimen of thionamide anti-thyroid drug to establish euthyroidism over 12–24 weeks. All underwent energy expenditure (EE) measurement within a chamber calorimeter, 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/magnetic resonance (PET/MR) imaging and plasma amino acids measurement during hyperthyroidism and euthyroidism. PET BAT maximum standardized uptake value (SUVmax), SUVmean and MR supraclavicular fat fraction (FF) quantified BAT activity. Twenty-two patients completed the study. Plasma BCAA level was significantly reduced in BAT-positive but not in BAT-negative patients during the transition from hyperthyroidism to euthyroidism. Plasma valine but not leucine and isoleucine correlated positively with insulin and HOMA-IR in hyperthyroidism. Plasma valine, leucine and isoleucine correlated with insulin and HOMA-IR in euthyroidism. Plasma valine correlated with insulin and HOMA-IR in BAT-negative but not in BAT-positive participants in both hyperthyroid and euthyroid state. However, the change (i.e. decrease) in plasma valine concentration from hyperthyroid to euthyroid state was affected by BAT-status. BAT utilizes and promotes BCAA plasma clearance from hyperthyroid to euthyroid state. Active BAT can potentially reduce circulating BCAA and may help to ameliorate insulin resistance and improve metabolic health.

Clinical trial registration: The trial was registered at clinicaltrials.gov as NCT03064542.

Weight Gain and Body Composition Changes during the Transition of Thyroid Function in Patients with Graves' Disease Undergoing Radioiodine Treatment

OBJECTIVE

This study aimed at investigating the dynamic changes in the body weight and body composition in a group of patients with Graves' disease undergoing radioiodine therapy.

METHODS

Seventeen patients with Graves' disease undergoing ¹³¹I treatment and forty-three euthyroid controls were recruited. Body weight, BMI, and body composition via bioelectrical impedance were measured for the participants at baseline, hypothyroid stage, and euthyroid stage.

RESULTS

Body weight increased significantly during the transition from hyperthyroidism to euthyroidism. However, there were no significant changes in body fat %, lean mass %, and bone mineral %. The body weight of 9 patients at the euthyroid stage exceeded their premorbid weight, while the remaining 8 patients' weight did not exceed the premorbid weight. In the group with excessive weight gain, both body fat and lean mass increased significantly. However, in the group without excessive weight gain, only lean mass increased significantly. The patients with excessive weight gain had significantly higher body fat %, while lower lean mass % compared to patients without excessive weight gain at baseline and at the euthyroid stage. Moreover, body fat % of patients with excessive weight gain was significantly higher than that of controls, while lean mass % was significantly lower than that of controls. There was no difference of body fat % and lean mass % between patients without excessive weight gain and controls.

CONCLUSION

¹³¹I treatment caused significant weight gain in patients with Graves' disease. An undesirable body composition at presentation may be a risk factor for excessive weight gain after hyperthyroidism treatment.

An unusual finding of giant fat-rich retroperitoneal masses in a patient with Graves' disease

We report the case of a 48-year-old man who was unexpectedly found by abdominal ultrasonography to have large retroperitoneal masses accompanied by Graves' disease. Computed tomography and magnetic resonance imaging further demonstrated giant fat-rich soft masses arising within both renal sinuses. Histopathological examination of the mass was performed twice at 5-year intervals, with both examinations indicating fatty tissue cells with chronic fibrous panniculitis. Intravenous pulse therapy and successive oral glucocorticoid therapy were ineffective against Graves' ophthalmopathy or mass lesion. An antithyroid hormone regimen was followed by subtotal thyroid resection, leading to improvements in hyperthyroidism. Mass growth then attenuated slowly as the thyroid hormones returned to normal levels. The long-term follow-up of this patient should carefully monitor the appearance of warning signs such as mass effects.

Weight gain following treatment of hyperthyroidism-A forgotten tale

Hyperthyroidism causes weight loss in the majority, but its effect is variable and 10% of patients gain weight. Its treatment usually leads to weight gain and some studies have reported an excess weight regain. However, there is considerable inter-individual variability and a differential effect on body weight by different treatments, with some studies reporting more weight increase with radioiodine, and perhaps surgery, compared with anti-thyroid drugs. The excess weight regain may relate to treatment-induced hypothyroidism. Furthermore, the transition from hyperthyroidism to euthyroidism may unmask, or exacerbate, the predisposition that some patients have towards obesity. Other risk factors commonly implicated for such weight increase include the severity of thyrotoxicosis at presentation and underlying Graves' disease. Conflicting data exist whether lean body mass or fat mass or both are increased post-therapy and whether such increments occur concurrently or in a sequential manner; this merits clarification. In any case, clinicians need to counsel their patients regarding this issue at presentation. Limited data on the effect of dietary interventions on weight changes with treatment of hyperthyroidism are encouraging in that they cause significantly lesser weight gain compared to standard care. More research is indicated on the impact of the treatment of hyperthyroidism on various anthropometric indices and the predisposing factors for any excessive weight gain. Regarding the impact of dietary management or other weight loss interventions, there is a need for well-designed and, ideally, controlled intervention studies.

Serum Fibroblast Growth Factor 21 Levels in Patients with Hyperthyroidism and its Association with Body Fat Percentage

BACKGROUND

Most of the actions of thyroid hormone (TH) on body metabolisms like maintenance of basal metabolic rate (BMR) and body fat are similar to that of fibroblast growth factor 21 (FGF21). We hypothesized that in patients with hyperthyroidism, the pathological changes in the BMR, body fat are mediated by TH through FGF21.

OBJECTIVES

To study the association of serum FGF21 levels with hyperthyroidism and correlate body fat percentage with serum FGF21 levels in hyperthyroid patients.

STUDY DESIGN

Case-control prospective follow-up study.

METHODOLOGY

A total of 68 hyperthyroid patients and age, sex-matched healthy controls who fulfilled the inclusion and exclusion criteria were studied. Among them, 45 cases were followed up at 3 to 6 months after the achievement of euthyroidism. Body fat percentage was calculated from Jackson and Pollock 3 site equation and Siri equation. BMR percentage was calculated by the Gale formula.

RESULTS

The mean age in years in the cases was similar to that of controls (36.14 ± 10.01 vs. 36.57 ± 10.53, P = 0.81). The serum FGF21 levels at baseline were significantly elevated in patients with hyperthyroidism compared to controls [median 406.6 pg/ml (interquartile range, 262.9-655.6) vs. 252.3 (125.1-341) P < 0.001] and declined dramatically following treatment with anti-thyroid drugs [405 (275.5-680.4) vs. 203.6 (154.6-230.6) P < 0.001]. Serum FGF21 levels negatively correlated with body fat percentage (r = -0.268, P = 0.002). After adjusting to various confounding factors, serum FGF21 was independently associated with hyperthyroidism and was significant. (OR [95%CI] 3.78 (1.046-13.666) P = 0.043).

CONCLUSION

Serum FGF21 levels were elevated in hyperthyroid patients and decreased following treatment with anti-thyroid drugs. It was independently associated with hyperthyroidism. There may be a future therapeutic role of FGF21 inhibition in the reversal of these changes in addition to anti-thyroid drugs in patients with hyperthyroidism.

Impact of thyroid hormones on asthma in older adults

Objective

Thyroid hormones affect airway contraction, but the specific effects of thyroid hormones on airways are controversial.

Methods

We divided 78 advanced-age men with asthma into 3 groups: type I respiratory failure (RF1), type II respiratory failure (RF2), and no respiratory failure (NRF). Pulmonary function was measured after asthma stabilization.

Results

The free triiodothyronine (FT3) level was significantly higher in the RF1 than RF2 group, but the free thyroxine (FT4), total thyroxine (TT4), and thyroid-stimulating hormone (TSH) levels were not significantly different. In the RF1, RF2, and NRF groups, the correlation coefficients between FT3 and the forced expiratory volume in1 s (FEV₁) were 0.317, 0.627, and 0.213; those between FT3 and the FEV₁/forced vital capacity (FVC) ratio were 0.287, 0.412, and 0.156; those between FT4 and FEV₁ were 0.214, 0.231, and 0.167; and those between FT4 and the FEV₁/FVC ratio were 0.211, 0.215, and 0.218, respectively. In the RF1 and RF2 groups, the correlation coefficients between the sum activity of peripheral deiodinases (SPINA-GD) and the FEV₁/FVC ratio were 0.164 and 0.421, and those between SPINA-GD and FEV₁ were 0.284 and 0.491, respectively.

Conclusion

The correlation between FT3 and pulmonary function is likely caused by changes in thyroid enzymology.

Thyroid Hormone Action and Energy Expenditure

Energy metabolism is one of the most recognized targets of thyroid hormone action, which indeed plays a critical role in modulating energy expenditure in all of its components. This is because thyroid hormone receptors are ubiquitous, and thyroid hormones interact and influence most metabolic pathways in virtually all systems throughout the entire life of the organism. The pleiotropic actions of thyroid hormone are the results of interaction between the local availability of T3 and the signal transduction machinery, which confer in physiologic conditions time and tissue specificity of the hormonal signal despite negligible variations in circulating levels. Historically, the measurement of energy expenditure has been used as the gold standard for the clinical assessment of the hormonal action until the advent of the immunoassays for TSH and thyroid hormone, which have since been used as proxy for measurement of thyroid hormone action. Although the clinical correlates between thyroid hormone action and energy expenditure in cases of extreme dysfunction (florid hyperthyroidism or hypothyroidism) are well recognized, there is still controversy on the effects of moderate, subclinical thyroid dysfunction on energy expenditure and, ultimately, on body weight trajectory. Moreover, little information is available on the effects of thyroid hormone replacement therapy on energy expenditure. This mini review is aimed to define the clinical relevance of thyroid hormone action in normal physiology and functional disorders, as well the effects of thyroid hormone therapy on energy expenditure and the effects of changes in energy status on the thyroid hormone axis.