Prevalence of Subclinical Hypothyroidism in a Morbidly Obese Population and Improvement after Weight Loss Induced by Roux-en-Y Gastric Bypass

Moraes, Cristiane Martins Moulin de; Mancini, Márcio C.; Melo, Maria Edna de; Figueiredo, Daniela Andraus; Villares, S M; Rascovski, A.; Zilberstein, Bruno; Halpern, Alfredo

doi:10.1381/096089205774512537

Cited by 115 publications

(92 citation statements)

References 30 publications

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“…This observational finding is compatible with the hypothesis that reductions in BMI may enhance effects of and sensitivity to incretin hormones, such as GLP-1. An increased sensitivity after RYGB has also been described for other hormones, i.e., insulin and thyroxin, independent of weight reduction (28,29). Although it could be considered contradictory to the often observed effect that increased hormonal levels leads to desensitization of the corresponding hormonal receptor, as postprandial GLP-1 levels are increased after RYGB, we do speculate that increased sensitivity for GLP-1 may explain our findings in the fasted state.…”

Section: Discussioncontrasting

confidence: 48%

Elevated Postoperative Endogenous GLP-1 Levels Mediate Effects of Roux-en-Y Gastric Bypass on Neural Responsivity to Food Cues

et al. 2017

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OBJECTIVEIt has been suggested that weight reduction and improvements in satiety after Rouxen-Y gastric bypass (RYGB) are partly mediated via postoperative neuroendocrine changes. Glucagon-like peptide-1 (GLP-1) is a gut hormone secreted after food ingestion and is associated with appetite and weight reduction, mediated via effects on the central nervous system (CNS). Secretion of GLP-1 is greatly enhanced after RYGB. We hypothesized that postoperative elevated GLP-1 levels contribute to the improved satiety regulation after RYGB via effects on the CNS. RESEARCH DESIGN AND METHODSEffects of the GLP-1 receptor antagonist exendin 9-39 (Ex9-39) and placebo were assessed in 10 women before and after RYGB. We used functional MRI to investigate CNS activation in response to visual food cues (pictures) and gustatory food cues (consumption of chocolate milk), comparing results with Ex9-39 versus placebo before and after RYGB. RESULTSAfter RYGB, CNS activation was reduced in the rolandic operculum and caudate nucleus in response to viewing food pictures (P = 0.03) and in the insula in response to consumption of palatable food (P = 0.003). GLP-1 levels were significantly elevated postoperatively (P < 0.001). After RYGB, GLP-1 receptor blockade resulted in a larger increase in activation in the caudate nucleus in response to food pictures (P = 0.02) and in the insula in response to palatable food consumption (P = 0.002). CONCLUSIONSWe conclude that the effects of RYGB on CNS activation in response to visual and gustatory food cues may be mediated by central effects of GLP-1. Our findings provide further insights into the mechanisms underlying the weight-lowering effects of RYGB.Bariatric surgery is currently the most effective therapeutic modality for severe obesity in terms of substantial weight loss and long-term efficacy (1). The most commonly performed procedure is Roux-en-Y gastric bypass surgery (RYGB), which comprises the formation of a small gastric pouch, which is connected to the midjejunum, bypassing the duodenum and proximal jejunum. This may lead to reduced ingestive capacity and

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Section: Discussioncontrasting

confidence: 48%

Elevated Postoperative Endogenous GLP-1 Levels Mediate Effects of Roux-en-Y Gastric Bypass on Neural Responsivity to Food Cues

et al. 2017

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“…Alagna et al 19 did not find changes in TSH levels 12 months after biliopancreatic diversion, while Chikunguwo et al 55 and Moulin de Moraes et al 56 did (using gastric bypass). All these studies used basal TSH concentration, whereas we used mean 24-h TSH levels to account for pulsatility.…”

Section: Discussionmentioning

confidence: 95%

Daylong pituitary hormones in morbid obesity: effects of bariatric surgery

et al. 2008

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Moderate obesity is known to be associated with multiple endocrine abnormalities. Less information is available on the hormonal status of patients with morbid obesity and on the effects of major weight loss. We studied 16 severely obese (BMI 40.6-69.9 kg/m 2 ) nondiabetic patients and 7 nonobese (BMI range 24.6-27.7 kg/m 2 ), sex-and age-matched healthy volunteers. During 24 h in a metabolic ward, four meals were administered and hourly blood samples were drawn from a central venous catheter for the measurement of glucose, insulin, leptin, thyrotropic hormone (TSH), growth hormone (GH) and prolactin. Insulin sensitivity was measured by a euglycaemic hyperinsulinaemic clamp. Studies were repeated 6 months after biliopancreatic diversion, a mainly malabsorptive surgical approach, which caused an average weight loss of 35±4 kg (or 26 ± 2% of initial weight). Compared with controls, patients were hyperinsulinaemic (290 ± 31 vs 88 ± 4 pmol l À1 , P ¼ 0.0002), insulin resistant (23.5±2.8 vs 52.9±4.9 mmol min À1 kg FFM À1 , P ¼ 0.0006) and hyperleptinaemic (52.5±5.8 vs 10.9±3 ng ml À1 , P ¼ 0.0002). Plasma TSH levels were increased throughout the day-night cycle (averaging 2.02 ± 0.18 vs 1.09 ± 0.19 mU ml À1 of controls, P ¼ 0.01), whereas serum GH levels were suppressed (0.46±0.10 vs 3.01±1.15, P ¼ 0.002). Following surgery, the hyperinsulinaemia and insulin resistance were fully normalized; in concomitance with a major drop in leptin levels (to 14.4±2.7 ng ml À1 , P ¼ 0.02), TSH decreased and GH increased to near-normal levels. In the whole dataset, mean 24-h leptin levels were directly related to mean 24-h TSH levels after controlling for confounders this relationship was lost only after adjusting for fat mass. We conclude that in morbid obesity leptin is a determinant of changes in pituitary function.

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“…Isolated hyperthyrotropinemia is often observed in patients with morbid obesity, but its pathogenesis remains poorly understood (17,19). Recent evidence showing that lack of female gender prevalence, normal FT 3 /FT 4 ratios, and normalization of serum TSH following weight loss all support the concept that these patients should not be considered as having subclinical hypothyroidism (19,(24)(25)(26). In agreement with this concept, we recently demonstrated that morbidly obese patients with a raised serum TSH have a significantly lower rate of thyroid Ab positivity when compared with TSH-matched normo-weight patients (19).…”

Section: Discussionmentioning

confidence: 99%

A hypoechoic pattern of the thyroid at ultrasound does not indicate autoimmune thyroid diseases in patients with morbid obesity

Rotondi¹,

Cappelli²,

Leporati³

et al. 2010

European Journal of Endocrinology

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Objective: Thyroid ultrasound (US) scan is a valuable tool for diagnosing thyroid diseases. In autoimmune thyroid disease (AITD), an hypoechoic pattern of the thyroid at US is related to circulating thyroid antibodies (Abs). The aim of this study was to evaluate the diagnostic accuracy of thyroid US for the detection of AITD in patients with morbid obesity. Design: Thyroid US scans showing an hypoechoic pattern of the thyroid were collected from 105 morbid obese patients (body mass index (BMI) O40 kg/m 2 ) and 105 non-obese patients (BMI%30 kg/m 2 ). Results: A thyroid hypoechoic pattern at US was consistent with clinical/biochemical features of AITD in 90/105 (85.7%) non-obese patients and in 22/105 (20.9%) morbid-obese patients (P!0.0001). By performing a complete thyroid work-up, including clinical examination, thyroid morphology, serum hormones, and auto-Ab measurements, the discrepancy between the US pattern and the results of the thyroid Ab tests was justified in 6/15 non-obese patients, and only in 1/83 morbid obese patients. Thus, an unexplained hypoechoic pattern of the thyroid at US, defined as negative tests for thyroid Ab and absence of justifying thyroid disturbances, was found in 2/105 (1.9%) non-obese patients and in 68/105 (64.8%) morbid obese patients (P!0.0001). Conclusions: Our results suggest that i) morbid obesity may affect thyroid morphology, and ii) an hypoechoic pattern of the thyroid at US, a well-established parameter for diagnosing AITD, has a poor diagnostic accuracy when patients with morbid obesity are taken into account.

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Prevalence of Subclinical Hypothyroidism in a Morbidly Obese Population and Improvement after Weight Loss Induced by Roux-en-Y Gastric Bypass

Abstract: Our data confirm that severe obesity is associated with increased TSH. The decrease in TSH was independent of BMI, but occurred in all SH patients. A putative effect of weight reduction on the improvement of SH in all patients may be an additional benefit of bariatric surgery.

Cited by 115 publications

References 30 publications

Elevated Postoperative Endogenous GLP-1 Levels Mediate Effects of Roux-en-Y Gastric Bypass on Neural Responsivity to Food Cues

Elevated Postoperative Endogenous GLP-1 Levels Mediate Effects of Roux-en-Y Gastric Bypass on Neural Responsivity to Food Cues

Daylong pituitary hormones in morbid obesity: effects of bariatric surgery

A hypoechoic pattern of the thyroid at ultrasound does not indicate autoimmune thyroid diseases in patients with morbid obesity

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