Spiroergometric assessment of cardiorespiratory fitness in subjects with severe obesity: A challenge of reference.

BACKGROUND AND AIMS: Severe obesity is associated with poor physical performance but objective data are scarce. METHODS AND RESULTS: Bicycle spiroergometry data with focus on peak oxygen uptake (V˙O2,peak) and workload (Wpeak) from 476 subjects with severe obesity (BMI ≥ 35.0 kg/m2; 70% women) were analysed. In a first step, V˙O2,peak values were compared with reference values calculated upon different formulas (Wassermann; Riddle). Thereafter, multivariate regression analyses were performed to identify determinants of cardiorespiratory fitness. Cardiorespiratory fitness reference classes for V˙O2,peak and Wpeak were established by stratifying the sample upon identified determinants. Absolute V˙O2,peak (1.87 ± 0.47 vs. 2.40 ± 0.59 l/min) and Wpeak (131 ± 26 vs. 168 ± 44 W) were lower in women than men (both p<0.001). Same pattern was found for relative V˙O2,peak and Wpeak, respectively (both p < 0.05). In women, measured V˙O2,peak was lower than predicted by Wasserman (p < 0.001) but not by Riddle (p = 0.961). In men, V˙O2,peak was lower than calculated by both Wasserman and Riddle formulas (both p ≤ 0.003). Multivariate analyses revealed height and age to be the main determinants of cardiorespiratory fitness in both sexes. Subsequent statistical analyses of calculated reference fitness classes revealed that V˙O2,peak and Wpeak differed between the age- and height-defined groups in both sexes (all p < 0.001). CONCLUSION: Data indicate that the evaluation of cardiorespiratory fitness in subjects with severe obesity is largely biased by selected references values for comparison. Our newly established reference fitness classes upon height and age might be helpful in the clinical context when dealing with obese patients.

Effect of morbid obesity, gastric banding and gastric bypass on esophageal symptoms, mucosa and function.

BACKGROUND: Obesity and gastroesophageal reflux disease (GERD) are commonly associated diseases. Bariatric surgery has been shown to have various impacts on esophageal function and GERD. Our aim was to evaluate changes in symptoms, endoscopic findings, bolus passage and esophageal function in patients after primary gastric bypass surgery as compared to patients converted from gastric banding to gastric bypass. METHODS: Obese patients scheduled for laparoscopic Roux-en-Y gastric bypass (naïve-to-bypass) and patients who previously underwent gastric banding and were considered for conversion from gastric banding to gastric bypass (band-to-bypass) were included. Patients rated esophageal and epigastric symptoms (100 point VAS) and underwent upper endoscopy, impedance-manometry, and modified "timed barium swallow" before/after surgery. RESULTS: Data from 66 naïve-to-bypass patients (51/66, 77 % females, mean age 41.2 ± 11.1 years) and 68 band-to-bypass patients (53/68, 78 % females, mean age 43.8 ± 10.0 years) were available for analysis. Esophageal symptoms, esophagitis, esophageal motility abnormalities and impaired esophageal bolus transit were more common in patients that underwent gastric banding compared to those that underwent gastric bypass. The majority of symptoms, lesions and abnormalities induced by gastric banding were decreased by conversion to gastric bypass. Esophagitis was present in 28/68 (41 %) and 13/47 (28 %) patients in the band-to-bypass group, pre- versus postoperatively, respectively, (p < 0.05). The percentage of swallows with normal bolus transit increased following transformation from gastric band to gastric bypass (57.9 ± 4.1 and 83.6 ± 3.4 %, respectively, p < 0.01). CONCLUSIONS: From an esophageal perspective, gastric bypass surgery induces less motility disorders and esophageal symptoms and should be therefore favored over gastric banding in difficult to treat obese patients at risk of repeated bariatric surgery.

A genetic variant in proximity to the gene LYPLAL1 is associated with lower hunger feelings and increased weight loss following Roux-en-Y gastric bypass surgery.

OBJECTIVE: Bariatric surgery is the most efficient treatment of severe obesity. We investigated to what extent BMI- or waist-hip ratio (WHR)-related genetic variants are associated with excess BMI loss (EBMIL) two years after Roux-en-Y gastric bypass (RYGB) surgery, and elucidated the affected biological pathways. METHODS: Two-hundred fifty-one obese patients (age: 43 ± 10.7, preoperative BMI: 45.1 ± 6.1 kg/m(2), 186 women) underwent RYGB surgery and were followed up after two years with regard to BMI. Patients were genotyped for 32 single-nucleotide polymorphisms (SNPs) that were investigated with regard to their impact on response to RYGB and preoperatively measured Three Factor Eating Questionnaire (TFEQ) scores. RESULTS: Homozygous T carriers of the SNP rs4846567 in proximity to the Lysophospholipase-like 1 (LYPLAL1) gene showed a 7% higher EBMIL compared to wild-type and heterozygous carriers (p = 0.031). TT-allele carriers showed furthermore lower scores for Hunger (74%, p < 0.001), lower Disinhibition (53%, p < 0.001), and higher Cognitive restraint (21%, p = 0.017) than GG/GT carriers in the TFEQ. Patients within the lowest quartile of Hunger scores had a 32% greater EBMIL compared to patients in the highest quartile (p < 0.001). CONCLUSION: The LYPLAL1 genotype is associated with differences in eating behavior and loss of extensive body weight following RYGB surgery. Genotyping and the use of eating behavior-related questionnaires may help to estimate the RYGB-associated therapy success.

Eating behaviour in treatment-seeking obese subjects - Influence of sex and BMI classes.

Obese subjects frequently show an adversely altered eating behaviour. However, little is known on differences in eating behaviour across different degree of obesity. We analysed data on the three factor eating questionnaire assessing cognitive restraint, disinhibition, and hunger that were filled in by 664 obese patients (469 women) who seeked treatment in our Interdisciplinary Obesity Center. Patients were divided in five BMI classes (30 - <35 kg/m(2), 35 - <40 kg/m(2), 40 - <50 kg/m(2), and >50 kg/m(2)). Multivariate regression analyses revealed that sex was significantly related to all three eating behaviour traits (all P < 0.042) but no significant relation to BMI (as a continuous variable) was observed. Women in comparison to men showed significantly higher cognitive restraint (9.7 ± 4.3 vs. 7.7 ± 4.4; P < 0.001) and disinhibition (9.0 ± 3.5 vs. 7.7 ± 3.5; P < 0.001) scores and also showed higher hunger scores (6.9 ± 3.7 vs. 6.3 ± 3.5; P = 0.042). Analyses on different BMI classes revealed that cognitive restraint decreased (P = 0.016) while disinhibition (P = 0.010) and hunger (P = 0.044) increased independently of sex with increasing BMI classes. However, above the obesity grade I class (i.e. BMI 30 - < 35 kg/m(2)) there were no differences in eating behaviour variables between the remaining BMI classes. Data indicate profound differences in eating behaviour between women and men that persist across a wide range of obesity. Furthermore, data suggest that while grade I obese patients show higher cognitive restraint and less disinhibition and hunger scores than more severe obese patients these dimensions of eating behaviour do not systematically vary across higher BMI classes.

Perioperative blood transfusions do not impact overall and disease-free survival after curative rectal cancer resection: a propensity score analysis.

OBJECTIVE: To assess the putative impact of perioperative blood transfusions on overall and disease-free survival in patients undergoing curative resection of stage I-III rectal cancer by applying propensity-scoring methods. BACKGROUND: Whether perioperative blood transfusions negatively impact survival remains a matter of great debate. METHODS: In a single-center study, 401 patients undergoing open curative resection of stage I-III rectal cancer between 1996 and 2008 were assessed. The median follow-up was 34.2 months. Patients who did and did not receive perioperative blood transfusions were compared using Cox regression and propensity score analyses. RESULTS: Overall, 217 patients (54.1%) received blood transfusions. Patients' characteristics were highly biased concerning transfusions (propensity score 0.77±0.23 vs. 0.28±0.25; P<0.001). In unadjusted analysis, blood transfusions were associated with a 119% increased risk of mortality [hazard ratio (HR): 2.19, 95% confidence interval (CI): 1.34-3.57, P=0.001]. In propensity score-adjusted Cox regression (HR: 1.02, 95% CI: 0.65-1.58, P=0.970), blood transfusions did not increase the risk of overall survival. Similarly, in propensity score-adjusted Cox regression (HR: 0.86, 95% CI: 0.60-1.23, P=0.672), blood transfusions were not associated with an increased risk of recurrence. CONCLUSIONS: This is the first propensity score-based analysis providing compelling evidence that worse oncological outcomes after curative rectal cancer resection in patients receiving perioperative blood transfusions are caused by the clinical circumstances requiring transfusions, not due to the blood transfusions themselves. Therefore, concerns about overall and disease-free survival should be no issue in the decision-making regarding perioperative blood transfusions in patients undergoing curative rectal cancer resection.

A Rare Case of Papillary Thyroid Carcinoma in Marine-Lehnhart Syndrome-Indication for Biopsy of Hot Thyroid Nodules?

An uncommon occurrence in which Graves disease (GD) coincides with autonomous functioning thyroid nodules (AFTNs) is termed Marine-Lehnhart syndrome (MLS). While hyperfunctioning nodules in MLS are commonly benign, there exists a rare potential for malignancy. A 41-year-old male patient was initially managed conservatively upon being diagnosed with MLS type 1. However, the emergence of obstructive symptoms prompted a thyroidectomy 4 years after initial presentation. Histological analysis revealed 2 cervical lymph node metastases and papillary thyroid cancer (PTC) within the AFTN.

Early results of the Swiss Multicentre Bypass or Sleeve Study (SM-BOSS): a prospective randomized trial comparing laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass.

OBJECTIVE: Laparoscopic sleeve gastrectomy (LSG) has been proposed as an effective alternative to the current standard procedure, laparoscopic Roux-en-Y gastric bypass (LRYGB). Prospective data comparing both procedures are rare. Therefore, we performed a randomized clinical trial assessing the effectiveness and safety of these 2 operative techniques. METHODS: Two hundred seventeen patients were randomized at 4 bariatric centers in Switzerland. One hundred seven patients underwent LSG using a 35-F bougie with suturing of the stapler line, and 110 patients underwent LRYGB with a 150-cm antecolic alimentary and a 50-cm biliopancreatic limb. The mean body mass index of all patients was 44 ± 11.1 kg/m, the mean age was 43 ± 5.3 years, and 72% were female. RESULTS: The 2 groups were similar in terms of body mass index, age, sex, comorbidities, and eating behavior. The mean operative time was less for LSG than for LRYGB (87 ± 52.3 minutes vs 108 ± 42.3 minutes; P = 0.003). The conversion rate was 0.9% in both groups. Complications (<30 days) occurred more often in LRYGB than in LSG (17.2% vs 8.4%; P = 0.067). However, the difference in severe complications did not reach statistical significance (4.5% for LRYGB vs 1% for LSG; P = 0.21). Excessive body mass index loss 1 year after the operation was similar between the 2 groups (72.3% ± 22% for LSG and 76.6% ± 21% for LRYGB; P = 0.2). Except for gastroesophageal reflux disease, which showed a higher resolution rate after LRYGB, the comorbidities and quality of life were significantly improved after both procedures. CONCLUSIONS: LSG was associated with shorter operation time and a trend toward fewer complications than with LRYGB. Both procedures were almost equally efficient regarding weight loss, improvement of comorbidities, and quality of life 1 year after surgery. Long-term follow-up data are needed to confirm these facts.

Cardiorespiratory Fitness is Associated with Glycated Hemoglobin and Triglyceride Levels in Severely Obese Men: A Retrospective Clinical Data Analysis.

BACKGROUND: Even subjects with severe obesity show a wide range of metabolic health states, with some showing marked alterations in glucose and lipid metabolism whereas others do not. In severely obese women, we could recently show that the degree of cardiorespiratory fitness is, independently of body mass and age, associated with several markers of glucose and lipid metabolism. AIMS: In our retrospective study on a clinical data set, we questioned whether such an association also exists in severely obese men. METHODS: Cardiorespiratory fitness, i. e. workload (Wpeak) and oxygen uptake (V̇O2,peak) at peak exercise, was assessed by a bicycle spiroergometry in 133 severely obese men (all BMI>35 kg m-2). The following metabolic blood markers were also measured: Fasting serum glucose, insulin, triglycerides (TG), total, low-, high-density cholesterol (Chol, LDL, HDL), uric acid, and whole blood glycated hemoglobin (HbA1c). The Chol/HDL ratio and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) were also calculated. RESULTS: Multiple stepwise linear regression models including age, body mass, and smoking status as independent variables revealed that Wpeak and V̇O2,peak, explained 4.5 to 10.7% of variance in HbA1c and TG (all beta<- 0.22; all p<0.02). Including fat free mass instead of body mass in respective models revealed that both Wpeak and V̇O2,peak were predictors of HbA1c and TG (all beta<- 0.265; all p<0.013), respectively, while Wpeak also accounted for variance in glucose and Chol (both beta<- 0.259; both p<0.023). CONCLUSIONS: Similar to previous observations in women, our data indicate that cardiorespiratory fitness assessed by bicycle ergospirometry test is associated with glucose and lipid metabolism in severely obese men. The strength of the found associations suggest a mild to moderate influence of cardiorespiratory fitness on metabolic health in severe obesity.

Basal serum prolactin levels in obesity--unrelated to parameters of the metabolic syndrome and unchanged after massive weight loss.

BACKGROUND: Prolactin (PRL) has been proposed to play an important role in the pathophysiology of obesity. To further elucidate the relationship between PRL and obesity-related metabolic disturbances, we performed a large cross-sectional study and also reassessed serum PRL levels in a subsample approximately 1 year after gastric bypass surgery. METHODS: In the cross-sectional part of the study, we assessed basal serum PRL levels in 344 obese subjects (68% women; BMI mean+/-SD, 44.3+/-6.6 kg/m2; range 27.0-67.0 kg/m2) along with measurements of glucose, insulin, C-peptide, triglycerides, total cholesterol, LDL-cholesterol, HDL-cholesterol, high sensitive (hs) C-reactive protein, and fat mass assessed by bioelectrical impedance analysis. In 38 patients, we reassessed PRL levels approximately 1 year after they have undergone a gastric bypass operation. RESULTS: Women displayed higher basal PRL levels than men (9.0+/-4.8 vs. 7.9+/-3.6 microg/l, P=0.03). Basal PRL levels were neither significantly correlated with the BMI of the subjects (r=-0.05, P=0.77) nor with any other of the assessed variables (all r<0.16, P>0.06) even after adjusting for the influence of sex. After massive surgically induced weight loss that on average almost approached 50 kg, basal serum PRL levels remained completely unchanged (before vs. after, 9.1+/-6.0 vs. 9.2+/-4.6 microg/l, P=0.86). However, preoperative PRL levels significantly correlated with that assessed after the operation (r=0.47; P=0.005). CONCLUSIONS: In contrast to our expectation, we could detect neither any significant association between basal PRL levels and the degree of obesity or related metabolic disturbances nor any systematic changes in basal concentrations of the hormone after massive weight loss. In sum, our data do not support the notion of a major role of PRL in the pathophysiology of obesity.

Differential changes in dietary habits after gastric bypass versus gastric banding operations.

BACKGROUND: Reduction of food intake is an important mechanism by which bariatric procedures reduce body weight. However, only few studies have systematically assessed what patients actually eat after different types of bariatric operations. METHODS: Dietary habits were assessed by a food frequency questionnaire in 121 bariatric patients (48 gastric bypass patients, 73 gastric banding patients) during follow-up visits in our interdisciplinary obesity center as well as in 45 severely obese (body mass index (BMI)>35 kg/m2) and 45 nonobese (BMI<27 kg/m2) control subjects. RESULTS: As compared with nonobese control subjects, obese control subjects consumed more meat, white bread, and diet soft drinks. Gastric bypass patients showed an enhanced consumption of foods rich in protein such as poultry, fish, and eggs as well as of cooked vegetables, while the consumption of fatty sweets like chocolate, cake, biscuits, and cookies was found to be distinctly reduced in this patient group. In contrast, gastric banding patients reported on a reduced intake of pasta, white bread, and fresh fruits and, just like gastric bypass patients, also on an enhanced intake of poultry and fish. Direct comparison of dietary habits between the two bariatric patient groups revealed that gastric bypass patients consumed more frequently fresh fruits, eggs, and diet soft drinks but strikingly less chocolate than gastric banding patients. CONCLUSION: Collectively, data clearly point to distinct changes in dietary habits after bariatric operations which markedly differ between gastric bypass and gastric banding patients. Overall, it is tempting to conclude that gastric bypass operations lead to a healthier and a more balanced diet than gastric band implantations.

Evidence for the necessity to systematically assess micronutrient status prior to bariatric surgery.

BACKGROUND: Bariatric surgery has been proven the most effective treatment of morbid obesity, but micronutrient deficiency following bariatric surgery is a major concern. Increasing evidence points to a generally poor micronutrient status in obese subjects. METHODS: We assessed micronutrient status in 232 morbidly obese subjects (BMI > or = 35 kg/m(2)) prior to bariatric surgery. Serum albumin, calcium, phosphate, magnesium, ferritin, hemoglobin, zinc, folate, vitamin B(12), 25-OH vitamin D(3), and intact parathormone (iPTH) were determined. In a sub-sample of 89 subjects, we additionally assessed copper, selenium, vitamin B(1), B(3), B(6), A, and E levels. RESULTS: Deficiencies were found in 12.5% of the subjects for albumin, 8.0% for phosphate, 4.7% for magnesium, 6.9% for ferritin, 6.9% for hemoglobin, 24.6% for zinc, 3.4% for folate, and 18.1% for vitamin B(12). In addition, 25.4% showed a severe 25-OH vitamin D(3) deficiency, which was accompanied by a secondary hyperparathyroidism in 36.6% cases. Prevalence of albumin deficiency (p < 0.007) and of anemia (p < 0.003; in women only) significantly increased with BMI. Of note, 48.7% of the subjects showed at least one of the most prevalent deficiencies, i.e., vitamin B(12), zinc and severe 25-OH vitamin D(3) deficiency. In the sub-sample, 32.6% showed a selenium, 5.6% a vitamin B(3), 2.2% a vitamin B(6), and 2.2% a vitamin E deficiency. Copper, vitamin B(1), and vitamin A deficiency was found in none of the subjects. CONCLUSION: Data indicate a high prevalence of micronutrient deficiencies in morbidly obese subjects. Based on these results, we strongly recommend a systematic assessment of the micronutrient status in all candidates for bariatric surgery.

Seasonal variation in the deficiency of 25-hydroxyvitamin D(3) in mildly to extremely obese subjects.

BACKGROUND: Vitamin D deficiency is a common finding in obese subjects even before any bariatric operation. However, most previous studies reporting on high rates of vitamin D deficiency in obese subjects have not systematically controlled for seasonal variations. Furthermore, the existence of seasonal variation in serum 25-hydroxyvitamin D(3) levels has not been well documented in obese subjects so far. METHODS: Serum 25-hydroxyvitamin D(3) levels were measured in 248 obese subjects (body mass index: range, 30.1-68.9 kg/m(2)). Fat mass was determined using standard bioelectrical impedance analysis. RESULTS: Serum 25-hydroxyvitamin D(3) levels decreased with the increasing body mass index and fat mass (both P < 0.001) and showed a marked variation across the seasons of the year (P < 0.001), which was not affected by the degree of obesity. According to the variation in absolute levels, the prevalence of vitamin D deficiency (<50 nmol/l) was 3.8-fold higher during winter than during summer (91.2% vs. 24.3%; P < 0.001). CONCLUSION: Data show a marked seasonal variation in absolute serum 25-hydroxyvitamin D(3) concentrations and prevalence of vitamin D deficiency in subjects with mild to extreme obesity. Considering the increasing number of studies reporting on vitamin D deficiency in obesity, the present finding points to season as a crucial factor that should not be neglected when assessing serum levels of this vitamin in obese subjects.

Sagittal Abdominal Diameter does not Predict Metabolic Traits Better than Waist Circumference-Related Measures of Abdominal Obesity in Obese Subjects.

BACKGROUND: Recently, we showed that in subjects with a body mass index (BMI) >35 kg/m2 waist circumference (WC) is associated with metabolic traits but associations were weaker in men than in women. AIMS: To confirm our previous observation that anthropometric measures of abdominal obesity are closer linked to metabolic traits in obese women than obese men. To test whether sagittal abdominal diameter (SAD) provides a better prediction of metabolic traits in obese subjects than WC related measures. METHODS: SAD and WC along with metabolic traits were assessed in 204 women and 69 men (BMI 30.1-64.0 kg/m2). RESULTS: In women, abdominal obesity measures were associated with glycated hemoglobin levels (HbA1c), fasting serum glucose, insulin, triglycerides (TG), total cholesterol (Chol), high-density lipoprotein (HDL), and uric acid levels as well as Chol/HDL ratio and homeostatic model assessment of insulin resistance (HOMA-IR) independently of age and BMI. SAD predicted serum insulin and Chol better than WC, whereas WC was superior to SAD in predicting HbA1c, glucose, HOMA-IR, TG, HDL, Chol/HDL, and uric acid. Of note, the combination of SAD and WC provided a better prediction of insulin, HOMA-IR, TG, and uric acid than each of these anthropometric alone. In men, only fasting glucose, Chol, and uric acid levels were associated with abdominal obesity markers. CONCLUSION: Data show various associations between anthropometric measures of abdominal obesity and metabolic traits in obese women but overall much less in obese men. Most metabolic traits are better predicted by WC than by SAD.

Resting energy expenditure after Roux-en Y gastric bypass surgery.

BACKGROUND: The mechanisms by which Roux-en Y gastric bypass surgery (RYGB) provokes weight loss are incompletely understood. Enhanced energy expenditure may be one contributing mechanism. Previous results on changes in resting energy expenditure (REE) after RYGB are inconsistent. OBJECTIVES: The aim of the present study was to assess changes in REE after RYGB and whether REE predicts weight loss (percentage weight loss). SETTING: Obesity Clinic. METHODS: REE was measured by indirect calorimetry (mREE) before and 1 year after RYGB in 233 patients with severe obesity (175 women; all body mass index ≥35.0 kg·m-2) and mREE was compared with predicted REE (pREE) and expressed as percentage of pREE (%pREE). For calculation of pREE, 2 new equations were developed from an independent reference group of overweight and obese patients (852 patients; body mass index range: 27.4-73.0 kg·m-2) that were examined in exactly the same setting as the bariatric patients that were followed-up after RYGB. The new equations were based on either anthropometric (pREE-BM, %pREE-BM) or body composition (pREE-BC; %pREE-BC) parameters. RESULTS: After RYGB, absolute mREE was reduced by 20.4 ± 11.0% (-458 ± 277 kcal·d-1; P<.001). Compared with pREE-BM (post-%REE-BM) and pREE-BC (post-%REE-BC), mREE was 2.3 ± 9.4% and 1.6 ± 9.5%, respectively, higher (both P ≤ .03). Post-%pREE-BM and post- %pREE-BC after RYGB were positively correlated with percentage weight loss (r = .206 and r = .231; both P ≤ .003). CONCLUSIONS: Data indicate a slightly higher mREE than pREE after RYGB. Although the underlying mechanisms of this observation remain to be elucidated our finding may play a role for weight loss outcomes after the surgery.

QT Interval Shortening After Bariatric Surgery Depends on the Applied Heart Rate Correction Equation.

BACKGROUND: A shortening of electrocardiographic QT interval has been observed in obese subjects after weight loss, but previous results may have been biased by inappropriate heart rate (HR) correction. METHODS: Electrocardiography (ECG) recordings of 49 (35 females) severely obese patients before and 12 months after Roux-en-Y gastric bypass (RYGB) surgery were analysed. QT interval (QTc) was calculated by using four different equations, i.e. Bazett, Fridericia, Framingham and Hodges. RESULTS: Irrespectively of the used correction formula, QTc interval length was reduced after the surgery (QTcBazett -31 ± 18 ms; QTcFridericia -12 ± 15 ms; QTcFramingham -14 ± 15 ms; QTcHodges -9 ± 15 ms; all Ps < 0.001), but QTcBazett reduction was significantly greater than the reduction in QTc calculated upon the other three equations (all Ps < 0.001). Moreover, changes in QTcBazett (P < 0.001) but not in QTcFridericia, QTcFramingham and QTcHodges (all Ps > 0.05) were significantly correlated with concurrent changes in HR. Multivariate regression analyses revealed a significant independent association of serum insulin levels with QTcFridericia, QTcFramingham and QTcHodges values (all Ps < 0.05) preoperatively, whilst changes in QTc interval length after the surgery were not consistently associated to concurrent changes in metabolic traits. CONCLUSIONS: Our data show that the extent of weight loss-associated QTc interval shortening largely depends on the applied HR correction equation and appears to be overestimated when the most popular Bazett's equation is used.

Type 2 Diabetes is Associated with Lower Cardiorespiratory Fitness Independent of Pulmonary Function in Severe Obesity.

Both severe obesity and type 2 diabetes (T2DM) are associated with reduced pulmonary function and reduced cardiorespiratory fitness. We investigated whether T2DM further aggravates the impaired pulmonary function and cardiorespiratory fitness in subjects with severe obesity. In this cross-sectional study pulmonary function (forced expiratory volume within 1 s, FEV1; vital capacity, VC) was assessed in 65 severely obese subjects with T2DM (T2DM group) and 65 severely obese subjects without T2DM (non-T2DM group), pairwise matched for sex, age, weight, and height. In 30 of the matched pairs, cardiorespiratory fitness was assessed by an incremental bicycle test (peak workload, Wpeak, oxygen uptake, V̇O2,peak). FEV1 and VC did not differ between the T2DM and non-T2DM group (all p≥0.110), whereas Wpeak and V̇O2,peak - absolute values as well as relative to body mass - were significantly lower in subjects with T2DM compared to those without T2DM (all p≤0.030). Objective markers of maximal exertion, i. e., maximal heart rate and respiratory exchange ratio, did not differ between the 2 groups (both p≥0.245). The presence of T2DM in subjects with severe obesity is associated with lower cardiorespiratory fitness but with no further reduction in pulmonary function compared to subjects with severe obesity but without T2DM. While the cause-effect relationship of this association is not yet clear, these findings highlight the interplay between cardiorespiratory fitness and metabolic health, even in subjects with severe obesity.

Subjective and objective physical activity patterns after Roux-en Y gastric bypass surgery compared with non-operated obese and non-obese control women.

INTRODUCTION: Previous studies on physical activity after bariatric surgery provided inconsistent results. The aim of our study was to comprehensively assess physical activity by subjective (questionnaires) and objective (accelerometry) measures in women who had undergone Roux-en Y gastric bypass (RYGB) surgery and to compare results with those of women displaying grade II or higher obesity and of non-obese control women. METHODS: Our cross-sectional case-control study included 12 women in each group (RYGB, obese, non-obese). Wrist accelerometry was performed over 5 days. Two questionnaires were used to assess women's self-reported leisure- and work-time and sport-related physical activity. RESULTS: Accelerometry indicated a lower physical activity in RYGB women than in non-obese women in particular during the weekend (p=0.010), while there was no difference between RYGB and obese women (p=0.57). Questionnaires revealed that RYGB women self-report a greater leisure- and work-time physical activity than obese women and also greater work-related physical activity than non-obese women (all p≤0.032). In contrast, sport-related activities were reduced in RYGB as compared with non-obese women (p=0.011), while there was no difference between RYGB and obese women (p=0.51). Comparison of the obese and non-obese group revealed less leisure-time and sport-related activities in the obese women (both p≤0.002). DISCUSSION: Despite the preliminary character of our rather small study, data suggest a differential physical activity pattern in women who have previously undergone RYGB surgery that is characterized by rare sport activities, an increased subjective work-related physical activity and objectively reduced physical activity during the weekend as compared with non-obese control women.

Comprehensive assessment of physical functioning in bariatric surgery candidates compared with subjects without obesity.

BACKGROUND: Obesity appears to be associated with reduced physical performance, but comprehensive assessments of physical functioning are lacking in subjects with severe obesity, in particular in comparison with subjects without obesity. This precludes an objective assessment of the degree of impairment. OBJECTIVE: To compare motor skills and cardiopulmonary fitness between subjects with severe obesity (OB) (i.e., candidates for bariatric surgery) and control subjects without obesity (non-OB). SETTING: Cantonal Hospital, Switzerland. METHODS: Flexibility, movement speed, balance, maximal isometric strength, and cardiopulmonary fitness were tested in 45 OB (body mass index: 42.6±.9 kg/m(2); age: 35±1.7 years; 33 women) and 32 non-OB (body mass index: 23±.4 kg/m(2); age: 38.5±2.1 years; 25 women) subjects. RESULTS: In comparison with the non-OB group, the OB group showed reduced shoulder flexibility (P<.001) but comparable hamstrings flexibility (P = .3). Speed-related tasks (i.e., timed up-and-go test and timed lying-to-standing test) indicated that the OB group was slower than the non-OB group (all P<.007). Strength-related tasks indicated a greater absolute back muscle and knee-extensor strength (all P<.002) in the OB group with no difference in knee-flexor strength (both P>.8). However, when related to weight, the OB group showed reduced maximal strength (all P<.002). Bicycle spiroergometry indicated that absolute oxygen consumption at peak exercise and at the anaerobic threshold did not differ between groups (both P>.06). Related to weight, however, values were lower in the OB than in the non-OB group (both P< .001). CONCLUSION: Data indicate a differential pattern of functional impairment in bariatric surgery candidates compared with subjects without obesity. These findings might help to establish tailored intervention protocols to improve physical performance in such subjects.

A Genetic Risk Score Is Associated with Weight Loss Following Roux-en Y Gastric Bypass Surgery.

BACKGROUND: Currently, Roux-en Y gastric bypass (RYGB) is the most efficient therapy for severe obesity. Weight loss after surgery is, however, highly variable and genetically influenced. Genome-wide association studies have identified several single nucleotide polymorphisms (SNP) associated with body mass index (BMI) and waist-hip ratio (WHR). We aimed to identify two genetic risk scores (GRS) composed of weighted BMI and WHR-associated SNPs to estimate their impact on excess BMI loss (EBMIL) after RYGB surgery. METHODS: Two hundred and thirty-eight obese patients (BMI 45.1 ± 6.2 kg/m(2), 74 % women), who underwent RYGB, were genotyped for 35 BMI and WHR-associated SNPs and were followed up after 2 years. SNPs with high impact on post-surgical weight loss were filtered out using a random forest model. The filtered SNPs were combined into a GRS and analyzed in a linear regression model. RESULTS: An up to 11 % lower EBMIL with higher risk score was estimated for two GRS models (P = 0.026 resp. P = 0.021) composed of seven BMI-associated SNPs (closest genes: MC4R, TMEM160, PTBP2, NUDT3, TFAP2B, ZNF608, MAP2K5, GNPDA2, and MTCH2) and of three WHR-associated SNPs (closest genes: HOXC13, LYPLAL1, and DNM3-PIGC). Patients within the lowest GRS quartile had higher EBMIL compared to patients within the other three quartiles in both models. CONCLUSIONS: We identified two GRSs composed of BMI and WHR-associated SNPs with significant impact on weight loss after RYGB surgery using random forest analysis as a SNP selection tool. The GRS may be useful to pre-surgically evaluate the risks for patients undergoing RYGB surgery.

The Role of FTO and Vitamin D for the Weight Loss Effect of Roux-en-Y Gastric Bypass Surgery in Obese Patients.

BACKGROUND: A recent study in children demonstrated that the rs9939609 single-nucleotide polymorphism in the fat mass and obesity (FTO) gene influences prospective weight gain, however, only in those who were vitamin D-deficient. If this might also be the case for Roux-en-Y gastric bypass (RYGB), surgery-induced weight loss is however unknown. The objective of this study is to examine if the magnitude of RYGB surgery-induced weight loss after 2 years depends on patients' FTO rs9939609 genotype (i.e., TT, AT, and AA) and presurgery vitamin D status (<50 nmol/L equals deficiency). METHODS: Before and at 24 months after RYGB surgery, BMI was measured in 210 obese patients (mean BMI 45 kg/m(2), 72 % females). Serum 25-hydroxyvitamin D3 levels were also repeatedly measured. Following surgery, vitamin D was supplemented. Possible weight loss differences between genotypes were tested with multiple linear regressions. RESULTS: The per-allele effect of each FTO A-allele on excessive BMI loss (EBMIL) was 3 % (P = 0.02). When split by baseline status, the EBMIL of vitamin D-deficient patients carrying AA exceeded that of vitamin D-deficient patients carrying TT by ~14 % (P = 0.03). No such genotypic differences were found in patients without presurgery vitamin D deficiency. Post-surgery serum levels of vitamin D did not differ between groups. CONCLUSIONS: Our data suggest that presurgery vitamin D levels influence the size of genotype effects of FTO rs9939609 on RYGB surgery-induced weight loss in obese patients.