Thyroid Homeostasis After Bariatric Surgery in Obese Cases

Gökosmanoğlu, Feyzi; Aksoy, Erkan; Önmez, Attila; Ergenç, Hasan; Topkaya, Sibel

doi:10.1007/s11695-019-04151-5

Cited by 23 publications

(14 citation statements)

References 16 publications

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“…L-T4 dosage requirements decrease in parallel with weight loss to yield similar TSH levels in both types of surgery. In our previous study we observed that TSH levels decreased in correlation with insulin resistance following bariatric surgery [6]. Juiz-Valiña et al [7] also reported similar findings.…”

Section: Discussionsupporting

confidence: 59%

Changes in levothyroxine pharmacokinetics following bariatric surgery in obese hypothyroid patients

Gökosmanoğlu

Önmez

2021

j-ebr

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Levothyroxine (L-T4) requirements in obese hypothyroid patients receiving L-T4 therapy decrease following bariatric surgery. L-T4 absorption is also thought to decrease after surgery. The purpose of this study was to evaluate L-T4 requirements in hypothyroidism cases before and after weight loss through bariatric surgery. Methods: Seventy-six cases of hypothyroidism receiving L-T4 replacement therapy and with a body mass index over 40 kg/m2 were included in the study. Patients losing at least 10% of basal body weight following bariatric surgery were assessed in terms of thyroid hormone levels and L-T4 requirements over follow-up of at least one year. The L-T4 requirements of patients in whom euthyroidism was achieved were compared in terms of bariatric surgery procedures and hypothyroidism etiology. Results: Seventy-six patients (56 women, 20 men) with a mean age of 38 years (18-51) were included in the study. Mean weight before bariatric surgery was 121.6 ± 6.8 kg, and mean body mass index was 49.5 ± 1.6 kg/m 2 . Euthyroidism was confirmed at pre-and post-bariatric surgery evaluation. No statistically significant postoperative changes were determined in thyroid-stimulating hormone or free thyroxine-3 and -4 (p > 0.05). A statistically insignificant decrease was observed in L-T4 dosages after surgery in cases of Hashimoto's thyroiditis (p = 0.064). A statistically significant decrease was determined in L-T4 dosages in cases of non-Hashimoto hypothyroidism (p = 0.001). L-T4 requirements decreased in both surgical procedures (p = 0.001) Conclusion: Postoperative L-T4 requirements decrease with weight loss. In addition, no decrease appeared to occur in L-T4 absorption following the surgical procedures in this study.

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Section: Discussionsupporting

confidence: 59%

Changes in levothyroxine pharmacokinetics following bariatric surgery in obese hypothyroid patients

Gökosmanoğlu

Önmez

2021

j-ebr

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“…In accordance with these data, a recent study has found that TSH levels decreased in parallel with decreased BMI after bariatric surgery. However, no significant change was observed in FT4 or FT3 levels [30]. The differences between studies may be due to the type of bariatric surgery performed, the characteristics of the control group and the studied patients, or to the statistical power of the studies.…”

Section: Discussionmentioning

confidence: 88%

Central Resistance to Thyroid Hormones in Morbidly Obese Subjects Is Reversed after Bariatric Surgery-Induced Weight Loss

Juiz-Valiña

Cordido

Outeiriño-Blanco

et al. 2020

JCM

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Endocrine abnormalities are common in obesity, including altered thyroid function. The altered thyroid function of obesity may be due to a mild acquired resistance to the thyroid hormone. The aim of this study was to investigate the effect of weight loss after bariatric surgery (BS) on resistance to thyroid hormones in patients with extreme obesity compared with a control group. We performed an observational study evaluating patients with extreme obesity who underwent BS. We included 106 patients (83 women) and 38 controls (24 women). The primary endpoint was the thyrotroph thyroxine resistance index (TT4RI) and thyroid stimulating hormone (TSH) index (TSHRI). The parameters were studied before and after surgery. TSHRI and TT4RI were higher in the obese patients than in the control group. TT4RI and TSHI decreased significantly over time after surgery, with this decrease being associated with the excessive body mass index (BMI) loss and C-reactive protein (CRP). In extreme obesity, BS promotes a significant decrease in the increased TT4RI and TSHI. This decrease of TT4RI and TSHI is progressive over time after BS and significantly associated with excess BMI lost and CRP. Extreme obesity is characterized by a mild reversible central resistance to thyroid hormones.

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“…However, the mechanism involved in the increase in TSH and FT3 levels in obese patients is unclear. Gokosmanoglu et al postulate that the underlying mechanism in TSH elevation is the development of resistance in TH receptors in target tissues of obese patients that reduces the effectiveness of the hormone in target tissues [ 24 ]. The study of Laclaustra has demonstrated that obese individuals with a steady consumption of high-calorie foods have an elevated risk of thyroid hormone resistance [ 25 ].…”

Section: Discussionmentioning

confidence: 99%

Association between Thyroid Function and Nonalcoholic Fatty Liver Disease in Euthyroid Type 2 Diabetes Patients

Huang

Yang

2020

Journal of Diabetes Research

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Thyroid function and type 2 diabetes mellitus (T2DM) are both associated with increased risks of adverse clinical outcomes in nonalcoholic fatty liver disease (NAFLD). Our study is aimed at evaluating the association between thyroid function and NAFLD in T2DM patients with normal thyroid function (euthyroid) and analyzing the potential effects of metformin on the pathological process. Overall, 369 T2DM patients were enrolled between July 2017 and September 2018 and stratified into NAFLD and non-NAFLD groups. Data on age, gender, body mass index (BMI, kg/m2), metformin use, and basal metabolic rate (BMR) were obtained from participants’ records. All patients were tested for biochemical markers, indexes of glucose metabolism, lipid metabolism, bone metabolism, and thyroid function at baseline. Multivariate analyses detected increased odds of NAFLD among individuals with T2DM per unit increase in their BMI and free triiodothyronine (FT3) and thyroid stimulating hormone (TSH); the odds ratios (OR) were 1.25, 3.02, and 1.58, respectively (all p<0.05). Positive correlations were detected between alanine aminotransferase (ALT) and FT3 (r=0.221, p=0.010), and negative correlations were noted between TSH and BMR (r=−0.618, p<0.001) and between BMR and FT3 (r=−0.452, p<0.001) in T2DM subjects with NAFLD. A significant difference in serum FT3 (t=2.468, p=0.0167) and TSH (t=2.658, p=0.010) levels was found between obese individuals with NAFLD who used and did not use metformin. The pathological mechanism of T2DM complicated by NAFLD in euthyroid patients may be associated with insulin resistance and a thyroid hormone resistance-like manifestation, i.e., relevant hypothyroidism. Metformin can potentially decrease the double-resistance situation, especially in obese individuals.

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Thyroid Homeostasis After Bariatric Surgery in Obese Cases

Cited by 23 publications

References 16 publications

Changes in levothyroxine pharmacokinetics following bariatric surgery in obese hypothyroid patients

Changes in levothyroxine pharmacokinetics following bariatric surgery in obese hypothyroid patients

Central Resistance to Thyroid Hormones in Morbidly Obese Subjects Is Reversed after Bariatric Surgery-Induced Weight Loss

Association between Thyroid Function and Nonalcoholic Fatty Liver Disease in Euthyroid Type 2 Diabetes Patients

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