Perceived Body Size in Relation to 10-Year Weight Change in the Swedish Obese Subjects Intervention Study

INTRODUCTION

Body size underestimation in patients with obesity may be associated with long-term weight increase. In the current report, we analyse changes in body size perception in patients with obesity undergoing either bariatric surgery or usual obesity care, and in subgroups of patients who gain weight or maintain their body weight over 10 years.

MATERIALS AND METHODS

A total of 2,504 patients with obesity from the prospective, controlled Swedish Obese Subjects (SOS) intervention study were included in this report, 1,370 patients underwent bariatric surgery and 1,134 patients were usual care controls. Weight was measured and body size was self-estimated using the Stunkard's figure rating scale at baseline and after 0.5, 1, 2, 3, 4, 6, 8 and 10 years of follow-up. A body perception index (BPI) was calculated as estimated/measured BMI. Weight (re)gain was defined as ≥10% increase between 1 and 10 years of follow-up.

RESULTS

Body size was underestimated by 12% in the surgery and 14% in the control group (i.e., >5 BMI units) at baseline and underestimation largely persisted over 10 years in both intervention groups. When stratified by long-term weight development, weight regainers from the surgery group underestimated their body size to a larger degree compared to weight maintainers (12 vs. 9%, p < 0.001) after 10 years. Likewise weight gainers in the control group also underestimated their body size to a larger degree (17% vs. 13%, p < 0.001). In both groups, the change in BPI was significantly different between weight regainers and maintainers during follow-up (time-BPI interactions both p < 0.001).

CONCLUSION

Patients with obesity underestimate their body size and this underestimation remains long-term even after major weight loss induced by bariatric surgery. In patients with obesity who maintain their weight, regardless of treatment, underestimation of body size persists but body size perception is slightly more accurate compared to patients who gain or regain weight long-term.

Life expectancy after bariatric surgery or usual care in patients with or without baseline type 2 diabetes in Swedish Obese Subjects

OBJECTIVES

To determine life expectancy and causes of death after bariatric surgery in relation to baseline type 2 diabetes (T2D) in the prospective, Swedish Obese Subjects study.

METHODS

The study included 2010 patients with obesity who underwent bariatric surgery and 2037 matched controls, eligible for surgery. The surgery group underwent gastric bypass (n = 265), banding (n = 376), or vertical banded gastroplasty (n = 1369). The control group (n = 2037) received usual obesity care. Causes of death were obtained from the Swedish Cause of Death Register, case sheets and autopsy reports, in patients with baseline T2D (n = 392 surgery patients/n = 305 controls) or non-T2D (n = 1609 surgery patients/n = 1726 controls) during a median follow-up 26 years.

RESULTS

In T2D and non-T2D subgroups, bariatric surgery was associated with increased life expectancy (2.1, 95% confidence interval (95% CI) 0.2-4.0; and 1.6, 0.5-2.7 years, respectively) and reduced overall mortality (adjusted hazard ratio (adjHR) = 0.77, 95% CI: 0.61-0.97; and 0.82, 0.72-0.94, respectively), and the treatment benefit was similar (interaction p = 0.615). Bariatric surgery was associated with reduced cardiovascular mortality in both subgroups (adjHR = 0.65, 95% CI: 0.46-0.91; and 0.70, 0.55-0.88, respectively (interaction p = 0.516)).

CONCLUSIONS

Bariatric surgery is associated with similar reduction of overall and cardiovascular mortality and increased life expectancy regardless of baseline diabetes status.

Long-term incidence of haematological cancer after bariatric surgery or usual care in the Swedish Obese Subjects study: a prospective cohort study

BACKGROUND

Bariatric surgery in people with obesity is associated with a reduced overall cancer risk. Retrospective studies indicate that bariatric surgery specifically might reduce the risk of haematological cancers, but there is an absence of data from long-term, prospective studies. We therefore studied the association between bariatric surgery and haematological cancer in the Swedish Obese Subjects study.

METHODS

The prospective controlled Swedish Obese Subjects study was designed to compare overall mortality in people who underwent bariatric surgery (n=2007) and usual care (n=2040). Participants were recruited through campaigns in mass media and at 480 primary health-care centres all over Sweden. The inclusion criteria were an age of 37-60 years and a BMI of 34 kg/m2 or more in men and 38 kg/m2 or more in women before or at the time of the examination. Haematological cancer events, including malignant lymphoma, myeloma, myeloproliferative neoplasms, as well as acute and chronic leukaemias, were captured from the Swedish Cancer Registry. The main outcome of this study was haematological cancer incidence and mortality. This study is registered with ClinicalTrials.gov (NCT01479452) and is ongoing.

FINDINGS

A total of 4047 individuals with obesity were enrolled between Sept 1, 1987, and Jan 31, 2001. Overall, 34 participants in the surgery group and 51 participants in the usual care control group were diagnosed with haematological cancer during follow-up (hazard ratio [HR] 0·60; 95% CI 0·39-0·92; p=0·020). Moreover, there were three deaths by haematological cancer in the surgery group and 13 deaths in the control group (0·22; 0·06-0·76; p=0·017). Surgery was also associated with a reduced incidence of lymphoma (0·45; 0·23-0·88; p=0·020). A significant difference in treatment effect between men and women was found; bariatric surgery was associated with reduced incidence of haematological cancer in women (0·44; 0·26-0·74; p=0·002), but not in men (1·35; 0·58-3·17; p=0·489; interaction p=0·031).

INTERPRETATION

Bariatric surgery is associated with a reduced incidence of haematological cancer, specifically in women. Health-care providers and policy makers working in the field of cancer prevention should consider bariatric surgery a primary prevention resource for people with obesity.

FUNDING

The Swedish Research Council, the Swedish State under the agreement between the Swedish Government and the county councils, the Avtal om Läkarutbildning och Forskning agreement, the Health & Medical Care Committee of the Region Västra Götaland, the Swedish Heart Lung Foundation, Gothenburg Medical Society, and the Adlerbert Research Foundation.

TRANSLATION

For the Swedish translation of the abstract see Supplementary Material section.

Development and validation of an interpretable machine learning-based calculator for predicting 5-year weight trajectories after bariatric surgery: a multinational retrospective cohort SOPHIA study

BACKGROUND

Weight loss trajectories after bariatric surgery vary widely between individuals, and predicting weight loss before the operation remains challenging. We aimed to develop a model using machine learning to provide individual preoperative prediction of 5-year weight loss trajectories after surgery.

METHODS

In this multinational retrospective observational study we enrolled adult participants (aged ≥18 years) from ten prospective cohorts (including ABOS [NCT01129297], BAREVAL [NCT02310178], the Swedish Obese Subjects study, and a large cohort from the Dutch Obesity Clinic [Nederlandse Obesitas Kliniek]) and two randomised trials (SleevePass [NCT00793143] and SM-BOSS [NCT00356213]) in Europe, the Americas, and Asia, with a 5 year follow-up after Roux-en-Y gastric bypass, sleeve gastrectomy, or gastric band. Patients with a previous history of bariatric surgery or large delays between scheduled and actual visits were excluded. The training cohort comprised patients from two centres in France (ABOS and BAREVAL). The primary outcome was BMI at 5 years. A model was developed using least absolute shrinkage and selection operator to select variables and the classification and regression trees algorithm to build interpretable regression trees. The performances of the model were assessed through the median absolute deviation (MAD) and root mean squared error (RMSE) of BMI.

FINDINGS

10 231 patients from 12 centres in ten countries were included in the analysis, corresponding to 30 602 patient-years. Among participants in all 12 cohorts, 7701 (75·3%) were female, 2530 (24·7%) were male. Among 434 baseline attributes available in the training cohort, seven variables were selected: height, weight, intervention type, age, diabetes status, diabetes duration, and smoking status. At 5 years, across external testing cohorts the overall mean MAD BMI was 2·8 kg/m2 (95% CI 2·6-3·0) and mean RMSE BMI was 4·7 kg/m2 (4·4-5·0), and the mean difference between predicted and observed BMI was -0·3 kg/m2 (SD 4·7). This model is incorporated in an easy to use and interpretable web-based prediction tool to help inform clinical decision before surgery.

INTERPRETATION

We developed a machine learning-based model, which is internationally validated, for predicting individual 5-year weight loss trajectories after three common bariatric interventions.

FUNDING

SOPHIA Innovative Medicines Initiative 2 Joint Undertaking, supported by the EU's Horizon 2020 research and innovation programme, the European Federation of Pharmaceutical Industries and Associations, Type 1 Diabetes Exchange, and the Juvenile Diabetes Research Foundation and Obesity Action Coalition; Métropole Européenne de Lille; Agence Nationale de la Recherche; Institut national de recherche en sciences et technologies du numérique through the Artificial Intelligence chair Apprenf; Université de Lille Nord Europe's I-SITE EXPAND as part of the Bandits For Health project; Laboratoire d'excellence European Genomic Institute for Diabetes; Soutien aux Travaux Interdisciplinaires, Multi-établissements et Exploratoires programme by Conseil Régional Hauts-de-France (volet partenarial phase 2, project PERSO-SURG).

Non-alcohol substance use disorder after bariatric surgery in the prospective, controlled Swedish Obese Subjects study

OBJECTIVE

The goal of this study was to investigate whether bariatric surgery is associated with substance use disorder (SUD) with substances other than alcohol.

METHODS

The prospective, controlled Swedish Obese Subjects study enrolled 2010 patients with obesity who underwent bariatric surgery (gastric bypass n = 265; vertical banded gastroplasty n = 1369; gastric banding n = 376) and 2037 matched control individuals receiving usual obesity care. Participants with SUD other than alcohol use disorder were identified using International Statistical Classification of Diseases (ICD) codes from the Swedish National Patient Register (covering treatment in hospital but not primary care). Those with a history of non-alcohol SUD were excluded. Median follow-up was 23.8 years.

RESULTS

During follow-up, non-alcohol SUD incidence rates per 1000 person-years with 95% CI were 1.6 (0.8-3.1), 0.8 (0.5-1.2), 1.1 (0.5-2.2), and 0.6 (0.4-0.8) for gastric bypass, vertical banded gastroplasty, gastric banding, and control individuals, respectively. Only gastric bypass was associated with increased incidence of non-alcohol SUD (adjusted hazard ratio 2.54 [95% CI: 1.14-5.65], p = 0.022) compared with control participants.

CONCLUSIONS

Gastric bypass surgery was associated with increased risk of non-alcohol SUD, and this should be considered in long-term postoperative care.

Evolution of age-related mutation-driven clonal haematopoiesis over 20 years is associated with metabolic dysfunction in obesity

BACKGROUND

Haematopoietic clones caused by somatic mutations with ≥2% variant allele frequency (VAF) increase with age and are linked to risk of haematological malignancies and cardiovascular disease. Recent observations suggest that smaller clones (VAF<2%) are also associated with adverse outcomes. Our aims were to determine the prevalence of clonal haematopoiesis driven by clones of variable sizes in individuals with obesity treated by usual care or bariatric surgery (a treatment that improves metabolic status), and to examine the expansion of clones in relation to age and metabolic dysregulation over up to 20 years.

METHODS

Clonal haematopoiesis-driver mutations (CHDMs) were identified in blood samples from participants of the Swedish Obese Subjects intervention study. Using an ultrasensitive assay, we analysed single-timepoint samples from 1050 individuals treated by usual care and 841 individuals who had undergone bariatric surgery, and multiple-timepoint samples taken over 20 years from a subset (n = 40) of the individuals treated by usual care.

FINDINGS

In this explorative study, prevalence of CHDMs was similar in the single-timepoint usual care and bariatric surgery groups (20.6% and 22.5%, respectively, P = 0.330), with VAF ranging from 0.01% to 31.15%. Clone sizes increased with age in individuals with obesity, but not in those who underwent bariatric surgery. In the multiple-timepoint analysis, VAF increased by on average 7% (range -4% to 24%) per year and rate of clone growth was negatively associated with HDL-cholesterol (R = -0.68, 1.74 E^-04).

INTERPRETATION

Low HDL-C was associated with growth of haematopoietic clones in individuals with obesity treated by usual care.

FUNDING

The Swedish Research Council, The Swedish state under an agreement between the Swedish government and the county councils, the ALF (Avtal om Läkarutbildning och Forskning) agreement, The Swedish Heart-Lung Foundation, The Novo Nordisk Foundation, The European Research Council, The Netherlands Organisation for Scientific Research.

Seeking lifestyle counselling at primary health care centres: a cross-sectional study in the Swedish population

BACKGROUND

Millions of people follow an unhealthy lifestyle in terms of tobacco consumption, hazardous use of alcohol, poor eating habits, and insufficient physical activity. Healthy lifestyles can to a large extent prevent and/or delay progression of non-communicable diseases. Factors influencing persons health-seeking behaviour regarding unhealthy lifestyles are of importance for sustainable health-promotive and disease-preventive work in primary health care. Generally, lifestyle interventions within primary health care are seen as feasible, but rarely reach all members of the general population. Few studies have been conducted about the likelihood among the general population to voluntarily contact a primary health care centre for support regarding lifestyle changes. The present study therefore aimed to investigate the general population's likelihood of contacting a primary health care centre regarding their lifestyles, and factors associated with a lower such likelihood.

METHODS

A probability sample of adults living in Sweden (n = 3 750) were invited to participate in a cross-sectional survey regarding how societal developments affect attitudes and behaviours of the adult Swedish population. Data were collected between September and December 2020. Participants completed a questionnaire about lifestyle changes, and the data were analysed using descriptive statistics, Chi-square test and logistic regression analysis.

RESULTS

The response rate was 52.0% (n = 1 896). Few persons responded that they would be likely to contact a primary health care centre for support regarding their lifestyles. Factors predicting a lower likelihood of contacting primary health care included few yearly visits to a primary health care centre, male sex, and living in a rural area.

CONCLUSIONS

Primary health care centres are not the first choice for lifestyle counselling for the majority of adults living in Sweden. We have identified factors predicting low likelihood of using the support available at these centres. In order to work with sustainable and visible health-promotive and disease-preventive strategies at primary health care centres, these settings need to find valid methods to involve and collaborate with the members of the general community, to meet the needs of a population struggling with unhealthy lifestyles.

Comparison of the novel WEst coast System for Triage (WEST) with Rapid Emergency Triage and Treatment System (RETTS©): an observational pilot study

Background

Most Swedish emergency departments (ED) use the triage system Rapid Emergency Triage and Treatment System (RETTS©), which over time has proven to prioritize patients to higher triage levels. When many patients are prioritized to high triage levels, challenges with identifying true high-risk patients and increased waiting time for these patients has emerged. In order to achieve a more balanced triage in relation to actual medical risk, the triage system WEst coast System for Triage (WEST) was developed, based on the South African Triage Scale (SATS). The aim of this study was to perform an initial evaluation of the novel emergency triage system WEST compared to the existing RETTS©.

Methods

Both RETTS© and WEST are five level triage systems illustrated by colors. Nurses from each of the three adult EDs of Sahlgrenska University Hospital in Gothenburg and the ambulance service assessed and triaged 1510 patients according to RETTS© and immediately thereafter filled out the WEST triage form. Data from each triage report were analyzed and grouped according to the triage color, chief complaint, and outcome of each patient. Data on discharge categories and events within 72 h were also collected. Data were analyzed with descriptive statistical methods.

Results

In general, WEST displayed lower levels of prioritization compared to RETTS©, with no observed impact on patients’ medical outcomes. In RETTS© orange triage level, approximately 50% of the patients were down prioritized in WEST to yellow or green triage levels. Also, in the RETTS© yellow triage level, more than 55% were down prioritized to green triage level in WEST. The number of patients who experienced a serious event during the first 72 h was few. Three patients died, these were all prioritized to red triage level in RETTS©. In WEST two of these patients were prioritized to red triage level and one to orange triage level. All these patients were admitted to hospital before deterioration.

Conclusions

WEST may reduce over prioritization at the ED, especially in the orange and yellow triage levels of RETTS©, with no observed increase in medical risk. WEST can be recommended for a clinical comparative study.

Heart failure in obesity: insights from proteomics in patients treated with or without weight-loss surgery

BACKGROUND

Obesity is associated with incident heart failure (HF), but the underlying mechanisms are unclear.

METHODS

We performed a nested case-control study within the Swedish-Obese-Subjects study, by identifying 411 cases who developed HF and matched them with respect to age, sex, weight-loss-surgery and length of follow-up with 410 controls who did not develop HF. In analyses corrected for multiple testing, we studied 182 plasma proteins known to be related to cardiovascular disease to investigate whether they could add to the understanding of the processes underlying obesity-related HF.

RESULTS

A total of 821 subjects were followed for 16 ± 6 years. Multivariable analysis adjusted for matching variables revealed that 32 proteins were significantly associated with HF. Twelve proteins were related to HF ≥ 80% of the time using a bootstrap resampling approach (false-discovery-rate [FDR] < 0.05): 11 were associated with increased HF-risk: TNFRSF10A*, ST6GAL1, PRCP, MMP12, TIMP1, CCL3, QPCT, ANG, C1QTNF1, SERPINA5 and GAL-9; and one was related to reduced HF-risk: LPL. An further 20 proteins were associated with onset of HF 50-80% of the time using bootstrap resampling (FDR < 0.05). A pathway analysis including all significant 32 proteins suggested that these biomarkers were related to inflammation, matrix remodeling, cardiometabolic hormones and hemostasis. Three proteins, C1QTNF1, FGF-21 and CST3, reflecting dyslipidemia and kidney disease, displayed a higher association with HF in patients who did not undergo weight-loss-surgery and maintained with obesity.

CONCLUSION

Pathways associated with HF in obesity include inflammation, matrix remodeling, cardiometabolic hormones and hemostasis; three protein biomarkers predicting HF appeared to be obesity-specific.

Association of Bariatric Surgery With Cancer Incidence in Patients With Obesity and Diabetes: Long-term Results From the Swedish Obese Subjects Study

OBJECTIVE

Obesity and type 2 diabetes are associated with serious adverse health effects, including cancer. Although bariatric surgery has been shown to reduce cancer risk in patients with obesity, the effect of bariatric surgery on cancer risk in patients with obesity and diabetes is less studied. We therefore examined the long-term incidence of cancer after bariatric surgery and usual care in patients with obesity and diabetes in the matched prospective Swedish Obese Subjects (SOS) study.

RESEARCH DESIGN AND METHODS

The SOS study examines long-term outcomes following bariatric surgery or usual care. The current analysis includes 701 patients with obesity and type 2 diabetes at baseline, 393 of whom underwent bariatric surgery and 308 who received conventional obesity treatment. Information on cancer events was obtained from the Swedish National Cancer Register. Median follow-up time was 21.3 years (interquartile range 17.6-24.8 years, maximum 30.7 years).

RESULTS

During follow-up, the incidence rate for first-time cancer was 9.1 per 1,000 person-years (95% CI 7.2-11.5) in patients with obesity and diabetes treated with bariatric surgery and 14.1 per 1,000 person-years (95% CI 11.2-17.7) in patients treated with usual obesity care (adjusted hazard ratio 0.63 [95% CI 0.44-0.89], P = 0.008). Moreover, surgery was associated with reduced cancer incidence in women (0.58 [0.38-0.90], P = 0.016), although the sex-treatment interaction was nonsignificant (P = 0.630). In addition, diabetes remission at the 10-year follow-up was associated with reduced cancer incidence (0.40 [0.22-0.74], P = 0.003).

CONCLUSIONS

These results suggest that bariatric surgery prevents cancer in patients with obesity and diabetes and that durable diabetes remission is associated with reduced cancer risk.

Long-term risk of anaemia after bariatric surgery: results from the Swedish Obese Subjects study

BACKGROUND

Nutritional deficiencies, such as iron and vitamin B12 deficiencies, are potential adverse consequences of bariatric surgery. Long-term data on anaemia after bariatric surgery are largely lacking. We aimed to investigate the risk of anaemia, iron and vitamin B12 deficiency anaemia, and vitamin B12 deficiency over 20 years in individuals who had bariatric surgery or received usual obesity care.

METHODS

The prospective, controlled Swedish Obese Subjects study recruited people with obesity via recruitment campaigns in the mass media and at primary health-care centres, and was done at 480 primary health-care centres and in 25 surgical departments in Sweden. Eligible participants were aged 37-60 years and had a BMI of either 34 kg/m² or more (for men) or 38 kg/m² or more (for women). Participants were excluded if they had undergone previous bariatric surgery or had contraindicating conditions. Two main groups were formed: those who chose bariatric surgery, the type of which was determined by the operating surgeon, and a contemporaneously matched control group, created by use of 18 matching variables, who received usual non-surgical obesity care that ranged from lifestyle advice to no treatment. Haemoglobin concentration was measured during examination visits at baseline and at 1 year, 2 years, 3 years, 4 years, 6 years, 8 years, 10 years, 15 years, and 20 years of follow-up. Anaemia was defined as a haemoglobin concentration of less than 120 g/L for women and 130 g/L for men. The primary, non-specified outcome was the incidence of anaemia, and was assessed in the as-treated population, which comprised only patients who received the actual treatment. The associations between treatment type and anaemia are expressed as unadjusted hazard ratios (HRs) and HRs adjusted for age, sex, BMI, menopausal status, education, diabetes, and hypertension, with 95% CIs. This study is registered in ClinicalTrials.gov, NCT01479452, and is closed to new participants, with follow-up ongoing.

FINDINGS

Between Sept 1, 1987, and Jan 31, 2001, 6905 individuals were assessed for eligibility, of whom 5335 were eligible. Of these, we included 2007 patients who chose bariatric surgery (266 in the gastric bypass group, 1365 in the vertical-banded gastroplasty group, and 376 in the gastric banding group) and 2040 matched controls who received usual obesity care. During a maximum of 20 years and a median of 10 years (IQR 3-20) of follow-up, there were 133 anaemia events in the gastric bypass group, 359 in the vertical-banded gastroplasty group, 101 in the gastric banding group, and 261 in the control group. Compared with the control group (13 cases per 1000 person-years, 95% CI 11-14), the incidence of anaemia was higher in the gastric bypass group (64 cases per 1000 person-years, 53-74; HR 5·05, 95% CI 3·94-6·48; p<0·0001), the vertical-banded gastroplasty group (23 cases per 1000 person-years, 21-26; 2·67, 2·25-3·18; p<0·0001), and the gastric banding group (26 per 1000 person-years, 21-31; 2·76, 2·15-3·52; p<0·0001). These associations remained after adjustment.

INTERPRETATION

Our findings highlight the increased risk of anaemia after bariatric surgery and the importance of long-term compliance to nutritional supplementation and monitoring to enable prevention and early detection of serious nutritional deficiencies after bariatric surgery.

FUNDING

Swedish Research Council, the Swedish state under the agreement between the Swedish Government and the county councils, the Swedish Diabetes Foundation, the Swedish Heart-Lung Foundation, and the Novo Nordisk Foundation.

Long-term incidence of hypoglycaemia-related events after bariatric surgery or usual care in the Swedish Obese Subjects study: A register-based analysis

AIMS

To examine the incidence of hypoglycaemia-related events over a period of up to 31 years in patients treated with bariatric surgery in the prospective, controlled Swedish Obese Subjects (SOS) study.

MATERIALS AND METHODS

The SOS study (n = 4047) is a prospective controlled intervention study. The present analysis included 1989 patients treated with bariatric surgery and 2027 control patients with obesity who received usual care. Diagnosed hypoglycaemia and events commonly attributed to hypoglycaemia (confusion, syncope, epilepsy and seizures), requiring hospital or specialist outpatient treatment, were identified by searching the National Patient Register. Analyses were stratified by baseline glycaemic status. Hazard ratios were adjusted for inclusion year, age, sex, smoking, glycated haemoglobin (HbA1c) level and body mass index at baseline. At the time of analysis (December 31, 2018), the median follow-up was 22 years.

RESULTS

Compared with usual care, bariatric surgery was associated with increased incidence of hypoglycaemia-related events in patients without baseline diabetes (168 and 219 events, respectively; log-rank P = .011), with a more pronounced risk during the first years of follow-up (test of time-treatment interaction P = .010). Multivariate analyses in patients without baseline diabetes indicated that male sex (P < .001), older age (P = .001) and higher HbA1c levels (P = .006) were associated with hypoglycaemia-related events. No association was found between risk of hypoglycaemia-related events and bariatric surgery in patients with baseline diabetes.

CONCLUSIONS

Bariatric surgery is associated with an increased incidence of hypoglycaemia-related events in patients without baseline diabetes, especially during the first years after treatment.

MiR-122-5p: A Novel Biomarker of Glucocorticoid Action

Background: Glucocorticoids are among the most prescribed medications for various indications, and treatment with glucocorticoids is associated with increased morbidity and mortality. A biomarker allowing quantification of glucocorticoid action could improve treatment safety and efficacy. Objective: To identify and validate circulating biomarkers of glucocorticoid action using a clinical experimental study and multi-omic network analysis. Methods: In a randomized, controlled, crossover, single-blind trial, 10 subjects without endogenous glucocorticoid production (Addison’s disease) received intravenous hydrocortisone infusion in a circadian pattern (physiological glucocorticoid exposure) or isotonic saline (glucocorticoid withdrawal) over 22 hours. Food intake and sample collections were standardized during both treatment periods. The transcriptomes of peripheral blood mononuclear cells and adipose tissue, plasma miRNAome and serum metabolome were collected at 7 AM (end of infusion). These multi-omic data were compared between the two interventions, within and between subjects, using network analysis of higher order interactions along with statistical and machine learning approaches. Samples from 120 subjects with varying glucocorticoid exposure from independent studies were used for the replication of the miRNA findings. The study was pre-registered at ClinicalTrials.gov with identifier NCT02152553. Results: We identified a transcriptomic profile derived from both peripheral blood mononuclear cells and adipose tissue, and a multi-omic signature including genes, miRNAs and metabolites that were associated with glucocorticoid exposure. Within the multi-omic signature we identified a single microRNA (miR-122-5p, p=0.009) regulated by glucocorticoid exposure, which we then replicated as a novel biomarker of glucocorticoid action in 120 subjects from independent studies (0.01 ≤ p ≤ 0.05). Conclusions: The discovery of miR-122-5p as a novel circulating biomarker of glucocorticoid action may have a significant impact on clinical practice. Our data also improves the understanding of glucocorticoid action and may have impact on future studies on the mechanistic understanding for the role of glucocorticoids in the etiology of common diseases, such as cardiovascular disease and obesity.

Identification of human glucocorticoid response markers using integrated multi-omic analysis from a randomized crossover trial

Background:

Glucocorticoids are among the most commonly prescribed drugs, but there is no biomarker that can quantify their action. The aim of the study was to identify and validate circulating biomarkers of glucocorticoid action.

Methods:

In a randomized, crossover, single-blind, discovery study, 10 subjects with primary adrenal insufficiency (and no other endocrinopathies) were admitted at the in-patient clinic and studied during physiological glucocorticoid exposure and withdrawal. A randomization plan before the first intervention was used. Besides mild physical and/or mental fatigue and salt craving, no serious adverse events were observed. The transcriptome in peripheral blood mononuclear cells and adipose tissue, plasma miRNAomic, and serum metabolomics were compared between the interventions using integrated multi-omic analysis.

Results:

We identified a transcriptomic profile derived from two tissues and a multi-omic cluster, both predictive of glucocorticoid exposure. A microRNA (miR-122-5p) that was correlated with genes and metabolites regulated by glucocorticoid exposure was identified (p=0.009) and replicated in independent studies with varying glucocorticoid exposure (0.01 ≤ p≤0.05).

Conclusions:

We have generated results that construct the basis for successful discovery of biomarker(s) to measure effects of glucocorticoids, allowing strategies to individualize and optimize glucocorticoid therapy, and shedding light on disease etiology related to unphysiological glucocorticoid exposure, such as in cardiovascular disease and obesity.

Funding:

The Swedish Research Council (Grant 2015-02561 and 2019-01112); The Swedish federal government under the LUA/ALF agreement (Grant ALFGBG-719531); The Swedish Endocrinology Association; The Gothenburg Medical Society; Wellcome Trust; The Medical Research Council, UK; The Chief Scientist Office, UK; The Eva Madura’s Foundation; The Research Foundation of Copenhagen University Hospital; and The Danish Rheumatism Association.

Clinical trial number:

NCT02152553.

Several diseases, including asthma, arthritis, some skin conditions, and cancer, are treated with medications called glucocorticoids, which are synthetic versions of human hormones. These drugs are also used to treat people with a condition call adrenal insufficiency who do not produce enough of an important hormone called cortisol. Use of glucocorticoids is very common, the proportion of people in a given country taking them can range from 0.5% to 21% of the population depending on the duration of the treatment. But, like any medication, glucocorticoids have both benefits and risks: people who take glucocorticoids for a long time have an increased risk of diabetes, obesity, cardiovascular disease, and death.

Because of the risks associated with taking glucocorticoids, it is very important for physicians to tailor the dose to each patient’s needs. Doing this can be tricky, because the levels of glucocorticoids in a patient’s blood are not a good indicator of the medication’s activity in the body. A test that can accurately measure the glucocorticoid activity could help physicians personalize treatment and reduce harmful side effects.

As a first step towards developing such a test, Chantzichristos et al. identified a potential way to measure glucocorticoid activity in patient’s blood. In the experiments, blood samples were collected from ten patients with adrenal insufficiency both when they were on no medication, and when they were taking a glucocorticoid to replace their missing hormones. Next, the blood samples were analyzed to determine which genes were turned on and off in each patient with and without the medication. They also compared small molecules in the blood called metabolites and tiny pieces of genetic material called microRNAs that turn genes on and off.

The experiments revealed networks of genes, metabolites, and microRNAs that are associated with glucocorticoid activity, and one microRNA called miR-122-5p stood out as a potential way to measure glucocorticoid activity. To verify this microRNA’s usefulness, Chantzichristos et al. looked at levels of miR-122-5p in people participating in three other studies and confirmed that it was a good indicator of the glucocorticoid activity.

More research is needed to confirm Chantzichristos et al.’s findings and to develop a test that can be used by physicians to measure glucocorticoid activity. The microRNA identified, miR-122-5p, has been previously linked to diabetes, so studying it further may also help scientists understand how taking glucocorticoids may increase the risk of developing diabetes and related diseases.

Long-term incidence of colorectal cancer after bariatric surgery or usual care in the Swedish Obese Subjects study

Bariatric surgery in patients with obesity is generally considered to reduce cancer risk in patients with obesity. However, for colorectal cancer some studies report an increased risk with bariatric surgery, whereas others report a decreased risk. These conflicting results demonstrate the need of more long-term studies analyzing the effect of bariatric surgery on colorectal cancer risk. Therefore, data from the Swedish Obese Subjects (SOS) study, ClinicalTrials.gov identifier: NCT01479452, was used to examine the impact of bariatric surgery on long-term incidence of colorectal cancer. The SOS study includes 2007 patients who underwent bariatric surgery and 2040 contemporaneously matched controls who received conventional obesity treatment. Patients in the surgery group underwent gastric bypass (n = 266), banding (n = 376) or vertical banded gastroplasty (n = 1365). Information on colorectal cancer events was obtained from the Swedish National Cancer Registry. Median follow-up was 22.2 years (inter-quartile range 18.3–25.2). During follow up there were 58 colorectal cancer events in the surgery group and 67 colorectal cancer events in the matched control group with a hazard ratio (HR) of 0.79 (95% CI:0.55–1.12; p = 0.183). After adjusting for age, body mass index, alcohol intake, smoking status, and diabetes, the adjusted HR was 0.89 (95% CI:0.62–1.29; p = 0.551). When analyzing rectal cancer events separately- 19 events in the surgery group and 31 events in the control group-a decreased risk of rectal cancer with surgery was observed (HR = 0.56; 95% CI:0.32–0.99; p = 0.045, adjusted HR = 0.61 (95% CI:0.34–1.10; p = 0.099), while the risk of colon cancer was unchanged. To conclude- in this long-term, prospective study, bariatric surgery was not associated with altered colorectal cancer risk.

Role of the Neutral Amino Acid Transporter SLC7A10 in Adipocyte Lipid Storage, Obesity, and Insulin Resistance

Elucidation of mechanisms that govern lipid storage, oxidative stress, and insulin resistance may lead to improved therapeutic options for type 2 diabetes and other obesity-related diseases. Here, we find that adipose expression of the small neutral amino acid transporter SLC7A10, also known as alanine-serine-cysteine transporter-1 (ASC-1), shows strong inverse correlates with visceral adiposity, insulin resistance, and adipocyte hypertrophy across multiple cohorts. Concordantly, loss of Slc7a10 function in zebrafish in vivo accelerates diet-induced body weight gain and adipocyte enlargement. Mechanistically, SLC7A10 inhibition in human and murine adipocytes decreases adipocyte serine uptake and total glutathione levels and promotes reactive oxygen species (ROS) generation. Conversely, SLC7A10 overexpression decreases ROS generation and increases mitochondrial respiratory capacity. RNA sequencing revealed consistent changes in gene expression between human adipocytes and zebrafish visceral adipose tissue following loss of SLC7A10, e.g., upregulation of SCD (lipid storage) and downregulation of CPT1A (lipid oxidation). Interestingly, ROS scavenger reduced lipid accumulation and attenuated the lipid-storing effect of SLC7A10 inhibition. These data uncover adipocyte SLC7A10 as a novel important regulator of adipocyte resilience to nutrient and oxidative stress, in part by enhancing glutathione levels and mitochondrial respiration, conducive to decreased ROS generation, lipid accumulation, adipocyte hypertrophy, insulin resistance, and type 2 diabetes.

Nursing students' experiences of a pedagogical transition from campus learning to distance learning using digital tools

Background

The use of distance education using digital tools in higher education has increased over the last decade, particularly during the COVID-19 pandemic. Therefore, this study aimed to describe and evaluate nursing students’ experiences of the pedagogical transition from traditional campus based learning to distance learning using digital tools.

Methods

The nursing course Symptom and signs of illness underwent a transition from campus based education to distance learning using digital tools because of the COVID-19 pandemic. This pedagogical transition in teaching was evaluated using both quantitative and qualitative data analysis. Focus group interviews (n = 9) were analysed using qualitative content analysis to explore students’ experiences of the pedagogical transition and to construct a web-based questionnaire. The questionnaire comprised 14 items, including two open-ended questions. The questionnaire was delivered to all course participants and responses were obtained from 96 of 132 students (73%). Questionnaire data were analyzed using descriptive statistics and comments from the open-ended questions were used as quotes to highlight the quantitative data.

Results

The analysis of the focus group interviews extracted three main dimensions: didactic aspects of digital teaching, study environment, and students’ own resources. Social interaction was an overall theme included in all three dimensions. Data from the questionnaire showed that a majority of students preferred campus based education and experienced deterioration in all investigated dimensions after the pedagogical transition. However, approximately one-third of the students appeared to prefer distance learning using digital tools.

Conclusions

The main finding was that the pedagogical transition to distance education reduced the possibility for students’ social interactions in their learning process. This negatively affected several aspects of their experience of distance learning using digital tools, such as reduced motivation. However, the heterogeneity in the responses suggested that a blended learning approach may offer pedagogical benefits while maintaining an advantageous level of social interaction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12912-021-00542-1.

Development of a BMI-Assigned Stunkard Scale for the Evaluation of Body Image Perception Based on Data of the SOS Reference Study

INTRODUCTION

Stunkard's figure rating scale is a widely used tool to assess weight status and, more recently, body image perception in people with obesity. However, large population-based studies on Europeans linking this scale's silhouettes with measured BMI values are lacking. Therefore, we used measured weight and height data from the Swedish Obese Subjects (SOS) reference cohort to assign a mean BMI to each of the 9 Stunkard Scale silhouettes and to define silhouette cutoff values for categorizing people with obesity and overweight.

METHODS

A total of 1,128 participants from the SOS reference cohort were included (54% females, BMI = 25.2 [ranging from 17.6 to 45.4] ±3.8 kg/m2, and age = 50 [ranging from 36 to 62] ±7 years [means ± standard deviation]). Patients estimated their own body size by choosing a silhouette of the Stunkard Scale. A mean BMI, based on measured weight and height, was assigned to each male and female silhouette of the Stunkard Scale. Measured BMI values were compared with BMI values calculated by simple linear regression analysis. ROC analysis was used to test accuracy of discrimination and the Youden index to assess optimal cutoff.

RESULTS

Figure ratings and BMI were strongly correlated in men, r (518) = 0.76, p < 0.001 and women, r (606) = 0.80, p < 0.001. Silhouette selection significantly predicted BMI values in men, β = 16.03, t (518) = 25.30, p < 0.001, and women, β = 12.06, t (606) = 32.98, p < 0.001, and explained a significant proportion of variance in BMI values in men, R2 = 0.55, F (1, 518) = 639.98, p < 0.001, and women, R2 = 0.64, F (1, 606) = 1,087.88, p < 0.001. ROC curve analyses resulted in an optimal cutoff value of 6 for identifying people with obesity and 5 for overweight.

CONCLUSION

Stunkard's figure rating scale can be used with confidence to assess weight status. Silhouette selection accurately classifies subjects as overweight or obese.

Association of Bariatric Surgery With Skin Cancer Incidence in Adults With Obesity: A Nonrandomized Controlled Trial

Importance

Obesity is a cancer risk factor, and bariatric surgery in patients with obesity is associated with reduced cancer risk. However, evidence of an association among obesity, bariatric surgery, and skin cancer, including melanoma, is limited.

Objective

To investigate the association of bariatric surgery with skin cancer (squamous cell carcinoma and melanoma) and melanoma incidence.

Design, Setting, and Participants

This nonrandomized controlled trial, the Swedish Obese Subjects (SOS) study, is ongoing at 25 surgical departments and 480 primary health care centers in Sweden and was designed to examine outcomes after bariatric surgery. The study included 2007 patients with obesity who underwent bariatric surgery and 2040 contemporaneously matched controls who received conventional obesity treatment. Patients were enrolled between September 1, 1987, and January 31, 2001. Data analysis was performed from June 29, 2018, to November 22, 2018.

Interventions

Patients in the surgery group underwent gastric bypass (n = 266), banding (n = 376), or vertical banded gastroplasty (n = 1365). The control group (n = 2040) received the customary treatment for obesity at their primary health care centers.

Main Outcomes and Measures

The SOS study was cross-linked to the Swedish National Cancer Registry, the Cause of Death Registry, and the Registry of the Total Population for data on cancer incidence, death, and emigration.

Results

The study included 4047 participants (mean [SD] age, 47.9 [6.1] years; 2867 [70.8%] female). Information on cancer events was available for 4042 patients. The study found that bariatric surgery was associated with a markedly reduced risk of melanoma (adjusted subhazard ratio, 0.43; 95% CI, 0.21-0.87; P = .02; median follow-up, 18.1 years) and risk of skin cancer in general (adjusted subhazard ratio, 0.59; 95% CI, 0.35-0.99; P = .047). The skin cancer risk reduction was not associated with baseline body mass index or weight; insulin, glucose, lipid, and creatinine levels; diabetes; blood pressure; alcohol intake; or smoking.

Conclusions and Relevance

The results of this study suggest that bariatric surgery in individuals with obesity is associated with a reduced risk of skin cancer, including melanoma.

Trial Registration

ClinicalTrials.gov identifier: NCT01479452.

Comparison of Preoperative Remission Scores and Diabetes Duration Alone as Predictors of Durable Type 2 Diabetes Remission and Risk of Diabetes Complications After Bariatric Surgery: A Post Hoc Analysis of Participants From the Swedish Obese Subjects Study

OBJECTIVE

Bariatric surgery is associated with diabetes remission and prevention of diabetes-related complications. The ABCD, DiaRem, Ad-DiaRem, DiaBetter, and individualized metabolic surgery scores were developed to predict short- to medium-term diabetes remission after bariatric surgery. However, they have not been tested for predicting durable remission nor the risk of diabetes complications, nor compared with diabetes duration alone.

RESEARCH DESIGN AND METHODS

We identified 363 individuals from the surgically treated group in the prospective Swedish Obese Subjects study with preoperative type 2 diabetes and for whom data (preoperative age, BMI, C-peptide, HbA_1c, oral diabetes medications, insulin use, and diabetes duration) were available for calculation of remission scores. Partial remission (after 2 and 10 years) was defined as blood glucose <6.1 mmol/L or HbA_1c <6.5% (48 mmol/mol) and no diabetes medication. Information on diabetes complications (at baseline and over 15 years of follow-up) was obtained from national health registers. Discrimination was evaluated by area under receiver operating characteristic curves (AUROCs).

RESULTS

For 2-year diabetes remission, AUROCs were between 0.79 and 0.88 for remission scores and 0.84 for diabetes duration alone. After 10 years, the predictive ability of scores decreased markedly (AUROCs between 0.70 and 0.76), and no score had higher predictive capacity than diabetes duration alone (AUROC = 0.73). For development of microvascular and macrovascular diabetes complications over 15 years, AUROCs for remission scores were 0.70-0.80 and 0.62-0.71, respectively, and AUROCs for diabetes duration alone were 0.77 and 0.66, respectively.

CONCLUSIONS

Remission scores and diabetes duration are good predictors of short-term diabetes remission. However, for durable remission and risk of complications, remission scores and diabetes duration alone have limited predictive ability.

Life Expectancy after Bariatric Surgery in the Swedish Obese Subjects Study

BACKGROUND

Obesity shortens life expectancy. Bariatric surgery is known to reduce the long-term relative risk of death, but its effect on life expectancy is unclear.

METHODS

We used the Gompertz proportional hazards regression model to compare mortality and life expectancy among patients treated with either bariatric surgery (surgery group) or usual obesity care (control group) in the prospective, controlled Swedish Obese Subjects (SOS) study and participants in the SOS reference study (reference cohort), a random sample from the general population.

RESULTS

In total, 2007 and 2040 patients were included in the surgery group and the control group, respectively, and 1135 participants were included in the reference cohort. At the time of the analysis (December 31, 2018), the median duration of follow-up for mortality was 24 years (interquartile range, 22 to 27) in the surgery group and 22 years (interquartile range, 21 to 27) in the control group; data on mortality were available for 99.9% of patients in the study. In the SOS reference cohort, the median duration of follow-up was 20 years (interquartile range, 19 to 21), and data on mortality were available for 100% of participants. In total, 457 patients (22.8%) in the surgery group and 539 patients (26.4%) in the control group died (hazard ratio, 0.77; 95% confidence interval [CI], 0.68 to 0.87; P<0.001). The corresponding hazard ratio was 0.70 (95% CI, 0.57 to 0.85) for death from cardiovascular disease and 0.77 (95% CI, 0.61 to 0.96) for death from cancer. The adjusted median life expectancy in the surgery group was 3.0 years (95% CI, 1.8 to 4.2) longer than in the control group but 5.5 years shorter than in the general population. The 90-day postoperative mortality was 0.2%, and 2.9% of the patients in the surgery group underwent repeat surgery.

CONCLUSIONS

Among patients with obesity, bariatric surgery was associated with longer life expectancy than usual obesity care. Mortality remained higher in both groups than in the general population. (Funded by the Swedish Research Council and others; SOS ClinicalTrials.gov number, NCT01479452.).

9p21.3 Coronary Artery Disease Locus Identifies Patients With Treatment Benefit From Bariatric Surgery in the Nonrandomized Prospective Controlled Swedish Obese Subjects Study

BACKGROUND

Sequence variation at chromosome 9p21.3 accounts for 20% of myocardial infarctions (MIs) in several populations. Whereas the risk conferred by the 9p21.3 locus appears to act independently of traditional risk factors, studies suggest that the association between 9p21.3 and MI is modified by glucose homeostasis and lifestyle. We examined if the 9p21.3 variant rs1333049, along with the previously identified predictor fasting insulin, modifies the preventive effect of bariatric surgery on MI incidence.

METHODS

rs1333049 was genotyped in 1852 patients treated by bariatric surgery and 1803 controls given usual care in the SOS study (Swedish Obese Subjects). MI incidence was determined using national registers. Median follow-up was 21 years (interquartile range 18-24 years).

RESULTS

Overall, 366 MIs occurred during follow-up. Among rs1333049 risk-allele carriers (CC+GC), the incidence of MI was reduced in the surgery group compared with the control group (hazard ratio=0.72 [95% CI, 0.57-0.92], P=0.008). By contrast, noncarriers (GG) showed no significant differences in MI incidence between the treatment groups (hazard ratio=1.28 [0.86-1.90], P=0.227; interaction between treatment and the risk-allele P=0.016). In addition, carriers with higher fasting insulin (above the median [17 mmol/L]) experienced significantly higher MI incidence than carriers with lower fasting insulin (hazard ratio=0.58 [0.42-0.78], P<0.001, interaction P=0.031).

CONCLUSIONS

In the SOS cohort, patients with the chromosome 9p21.3 rs1333049 risk allele together with high fasting insulin levels benefitted from bariatric surgery in terms of reduced incidence of MI. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01479452.

3-Hydroxyisobutyrate, A Strong Marker of Insulin Resistance in Type 2 Diabetes and Obesity That Modulates White and Brown Adipocyte Metabolism

Circulating branched-chain amino acids (BCAAs) associate with insulin resistance and type 2 diabetes. 3-Hydroxyisobutyrate (3-HIB) is a catabolic intermediate of the BCAA valine. In this study, we show that in a cohort of 4,942 men and women, circulating 3-HIB is elevated according to levels of hyperglycemia and established type 2 diabetes. In complementary cohorts with measures of insulin resistance, we found positive correlates for circulating 3-HIB concentrations with HOMA2 of insulin resistance, as well as a transient increase in 3-HIB followed by a marked decrease after bariatric surgery and weight loss. During differentiation, both white and brown adipocytes upregulate BCAA utilization and release increasing amounts of 3-HIB. Knockdown of the 3-HIB-forming enzyme 3-hydroxyisobutyryl-CoA hydrolase decreases release of 3-HIB and lipid accumulation in both cell types. Conversely, addition of 3-HIB to white and brown adipocyte cultures increases fatty acid uptake and modulated insulin-stimulated glucose uptake in a time-dependent manner. Finally, 3-HIB treatment decreases mitochondrial oxygen consumption and generation of reactive oxygen species in white adipocytes, while increasing these measures in brown adipocytes. Our data establish 3-HIB as a novel adipocyte-derived regulator of adipocyte subtype-specific functions strongly linked to obesity, insulin resistance, and type 2 diabetes.

Bariatric surgery and the incidence of rheumatoid arthritis - a Swedish Obese Subjects study

Objective

The aim of this study was to determine the effect of bariatric surgery on the incidence of RA in participants of the Swedish Obese Subjects (SOS) study.

Methods

The SOS is a longitudinal study aiming to assess the effect of bariatric surgery on mortality and obesity-related diseases. This report includes 2002 subjects with obesity who underwent bariatric surgery and 2034 matched controls; none of them had RA at baseline. Cases of incident RA were identified through the Swedish National Patient Register by searching for International Classification of Diseases codes. Both intention-to-treat analyses and per-protocol analyses are reported. In the per-protocol analysis, participants from the control group who underwent bariatric surgery later on during follow-up were censored at the time of surgery.

Results

During follow-up, 92 study participants developed RA. The median follow-up was 21 years (range 0–29). Bariatric surgery was neither associated with the incidence of RA in the intention-to-treat analysis [hazard ratio (HR) 0.92 (95% CI 0.59, 1.46), P = 0.74], nor in the per-protocol analysis [HR 0.86 (95% CI 0.54, 1.38), P = 0.53]. Weight change at the 2 year follow-up, expressed as the change in BMI compared with baseline, did not associate with the development of RA. Higher serum CRP levels and smoking associated with the future development of RA independent of other factors.

Conclusions

We did not detect any association between bariatric surgery and the incidence of RA in subjects affected by obesity followed up for up to 29 years.

ClinicalTrials.gov

(http://clinicaltrials.gov): NCT01479452.

Evaluation of Prediction Models for Type 2 Diabetes Relapse After Post-bariatric Surgery Remission: a Post hoc Analysis of 15-Year Follow-up Data from the Swedish Obese Subjects (SOS) Study

PURPOSE

Many patients achieve type 2 diabetes (T2D) remission after bariatric surgery, but relapse after post-surgery remission is common. Scoring models accurately predict remission up to 5 years after surgery but have not been tested for prediction of long-term T2D relapse. The aim of this work was to test the ability of prediction models and single predictors to identify patients at risk of long-term relapse (10-15 years) after post-surgery T2D remission.

METHODS

We identified 222 individuals with T2D from the surgically treated group in the prospective Swedish Obese Subjects study, who were in remission at the 2-year follow-up and had data available for prediction of long-term T2D relapse. T2D remission/relapse was assessed after 10 and 15 years. Model performance (discrimination) was evaluated by the area under the receiver operating characteristic (AUROC) curves.

RESULTS

Preoperative prediction of relapse using scores DiaRem, Ad-DiaRem, and DiaBetter and T2D duration alone was poor, as indicated by AUROC curves between 0.61-0.64 at 10 years and 0.62-0.66 at 15 years. Likewise, the 5y-Ad-DiaRem score, which includes early postoperative measures, resulted in AUROC curves of 0.65 and 0.70 for relapse at 10 and 15 years, respectively. Two-year weight change alone had higher discriminatory capacity than the 5y-Ad-DiaRem model at 10 years (AUROC = 0.70; p = 0.036) and similar capacity at 15 years (AUROC = 0.78; p = 0.188).

CONCLUSIONS

Predictive performance of all tested models is low for T2D relapse. By contrast, a single measure of 2-year weight change after surgery was associated with relapse, supporting a key role for initial weight reduction in long-term T2D control.

Failure of generic risk assessment model framework to predict groundwater pollution risk at hundreds of metal contaminated sites: Implications for research needs

Soil pollution constitutes one of the major threats to public health, where spreading to groundwater is one of several critical aspects. In most internationally adopted frameworks for routine risk assessments of contaminated land, generic models and soil guideline values are cornerstones. In order to protect the groundwater at contaminated sites, a common practice worldwide today is to depart from health risk-based limit concentrations for groundwater, and use generic soil-to-groundwater spreading models to back-calculate corresponding equilibrium levels (concentration limits) in soil, which must not be exceeded at the site. This study presents an extensive survey of how actual soil and groundwater concentrations, compiled for all high-priority contaminated sites in Sweden, relate to the national model for risk management of contaminated sites, with focus on As, Cu, Pb and Zn. Results show that soil metal concentrations, as well as total amounts, constitute a poor basis for assessing groundwater contamination status. The evaluated model was essentially incapable of predicting groundwater contamination (i.e. concentrations above limit values) based on soil data, and erred on the "unsafe side" in a significant number of cases, with modelled correlations not being conservative enough. Further, the risk of groundwater contamination was almost entirely independent of industry type. In essence, since neither soil contaminant loads nor industry type is conclusive, there is a need for a supportive framework for assessing metal spreading to groundwater accounting for site-specific, geochemical conditions.

Effects of Bariatric Surgery in Early- and Adult-Onset Obesity in the Prospective Controlled Swedish Obese Subjects Study

OBJECTIVE

Bariatric surgery is an effective treatment for obesity, but it is unknown if outcomes differ between adults with early- versus adult-onset obesity. We investigated how obesity status at 20 years of age affects outcomes after bariatric surgery later in life.

RESEARCH DESIGN AND METHODS

The Swedish Obese Subjects study is a prospective matched study performed at 25 surgical departments and 480 primary health care centers. Participants aged 37-60 years with BMI ≥34 kg/m² (men) or ≥38 kg/m² (women) were recruited between 1987 and 2001; 2,007 participants received bariatric surgery and 2,040 usual care. Self-reported body weight at 20 years of age was used to stratify patients into subgroups with normal BMI (<25 kg/m²), overweight (BMI 25-29.9 kg/m²), or obesity (BMI ≥30 kg/m²). Body weight, energy intake, and type 2 diabetes status were examined over 10 years, and incidence of cardiovascular and microvascular disease was determined over up to 26 years using data from health registers.

RESULTS

There were small but statistically significant differences in reduction of body weight among the subgroups after bariatric surgery (interaction P = 0.032), with the largest reductions among those with obesity aged 20 years. Bariatric surgery increased type 2 diabetes remission (odds ratios 4.51, 4.90, and 5.58 in subgroups with normal BMI, overweight, or obesity at 20 years of age, respectively; interaction P = 0.951), reduced type 2 diabetes incidence (odds ratios 0.15, 0.13, and 0.15, respectively; interaction P = 0.972), and reduced microvascular complications independent of obesity status at 20 years of age (interaction P = 0.650). The association between bariatric surgery and cardiovascular disease was similar in the subgroups (interaction P = 0.674). Surgical complications were similar in the subgroups.

CONCLUSIONS

The treatment benefits of bariatric surgery in adults are similar regardless of obesity status at 20 years of age.

Reoperations After Bariatric Surgery in 26 Years of Follow-up of the Swedish Obese Subjects Study

Importance

Bariatric surgery is an established treatment for obesity, but knowledge on the long-term incidence of revisional surgery is scarce.

Objective

To determine the incidence and type of revisional surgery after bariatric surgery in 26 years of follow-up of participants in the Swedish Obese Subjects (SOS) study.

Design, Setting, and Participants

The SOS study is a prospective nonrandomized controlled study comparing bariatric surgery (banding, vertical banded gastroplasty [VBG], and gastric bypass [GBP]) with usual care. The bariatric surgeries in the SOS study were conducted at 25 public surgical departments in Sweden. Men with body mass index values of 34 or higher and women with body mass indexes of 38 or higher were recruited to the surgery group of the SOS study between September 1, 1987, and January 31, 2001, and follow-up continued until December 31, 2014. Data analysis occurred from November 2016 to April 2018.

Interventions

Banding, VBG, or GBP.

Main Outcomes and Measures

Revisional surgeries, analyzed using data from questionnaires, hospital records, and the Swedish National Patient register through December 31, 2014.

Results

A total of 2010 participants underwent surgery. The age range was 37 to 60 years. A total of 376 participants underwent banding (18.7%), while 1365 had VBG (67.9%) and 266 had GBP (13.2%). During a median follow-up of 19 years, 559 participants (27.8%) underwent first-time revisional surgery, including 354 conversions to other bariatric procedures (17.6%), 114 corrective surgeries (5.6%), and 91 reversals to normal anatomy (4.5%). Revisional surgeries (conversions, corrective surgery, and reversals) were common after banding (153 of 376 [40.7%]) and VBG (386 of 1365 [28.3%]) but relatively rare after GBP (20 of 266 [7.5%]). Patients who had banding and VBG primarily underwent conversions to GBP or reversals. Incidence of reversals was 5 times higher after banding than after VBG (40.7% vs 7.5%; unadjusted hazard ratio, 5.19 [95% CI, 3.43-7.87]; P < .001). Corrective surgeries were equally common irrespective of the index surgery (72 of 1365 patients who had VBG [5.3%]; 23 of 376 patients who had banding [6.1%]; 19 of 266 patients who had GBP [7.1%]). Revisional surgery indications, including inadequate weight loss, band-associated complications (migration, stenosis, and slippage), staple-line disruptions, and postsurgical morbidity, varied depending on index surgery subgroup. Most corrections occurred within the first 10 years, whereas conversions and reversals occurred over the entire follow-up period.

Conclusions and Relevance

Corrective surgeries occur mainly within the first 10 years and with similar incidences across all 3 surgical subgroups, but indications varied. Conversions (mainly to GBP) and reversals occurred after many years and were most frequent after banding and VBG, reflecting a higher overall revisional surgery demand after these operations.

Associations of Bariatric Surgery With Changes in Interpersonal Relationship Status: Results From 2 Swedish Cohort Studies

Importance

Bariatric surgery is a life-changing treatment for patients with severe obesity, but little is known about its association with interpersonal relationships.

Objectives

To investigate if relationship status is altered after bariatric surgery.

Design, Setting, and Participants

Changes in relationship status after bariatric surgery were examined in 2 cohorts: (1) the prospective Swedish Obese Subjects (SOS) study, which recruited patients undergoing bariatric surgery from September 1, 1987, to January 31, 2001, and compared their care with usual nonsurgical care in matched obese control participants; and (2) participants from the Scandinavian Obesity Surgery Registry (SOReg), a prospective, electronically captured register that recruited patients from January 2007 through December 2012 and selected comparator participants from the general population matched on age, sex, and place of residence. Data was collected in surgical departments and primary health care centers in Sweden. The current analysis includes data collected up until July 2015 (SOS) and December 2012 (SOReg). Data analysis was completed from June 2016 to December 2017.

Main Outcomes and Measures

In the SOS study, information on relationship status was obtained from questionnaires. In the SOReg and general population cohort, information on marriage and divorce was obtained from the Swedish Total Population Registry.

Results

The SOS study included 1958 patients who had bariatric surgery (of whom 1389 [70.9%] were female) and 1912 matched obese controls (of whom 1354 [70.8%] were female) and had a median (range) follow-up of 10 (0.5-20) years. The SOReg cohort included 29 234 patients who had gastric bypass surgery (of whom 22 131 [75.6%] were female) and 283 748 comparators from the general population (of whom 214 342 [75.5%] were female), and had a median (range) follow-up of 2.9 (0.003-7.0) years. In the SOS study, the surgical patients received gastric banding (n = 368; 18.8%), vertical banded gastroplasty (n = 1331; 68.0%), or gastric bypass (n = 259; 13.2%); controls received usual obesity care. In SOReg, all 29 234 surgical participants received gastric bypass surgery. In the SOS study, bariatric surgery was associated with increased incidence of divorce/separation compared with controls for those in a relationship (adjusted hazard ratio [aHR] = 1.28; 95% CI, 1.03-1.60; P = .03) and increased incidence of marriage or new relationship (aHR = 2.03; 95% CI, 1.52-2.71; P < .001) in those who were unmarried or single at baseline. In the SOReg and general population cohort, gastric bypass was associated with increased incidence of divorce compared with married control participants (aHR = 1.41; 95% CI, 1.33-1.49; P < .001) and increased incidence of marriage in those who were unmarried at baseline (aHR = 1.35; 95% CI, 1.28-1.42; P < .001). Within the surgery groups, changes in relationship status were more common in those with larger weight loss.

Conclusions and Relevance

In addition to its association with obesity comorbidities, bariatric surgery-induced weight loss is also associated with changes in relationship status.

Expression of GHR and Downstream Signaling Genes in Human Adipose Tissue-Relation to Obesity and Weight Change

CONTEXT

GH is a strong regulator of metabolism. In obesity, both GH secretion and adipose tissue GHR gene expression are decreased. More detailed information on the regulation of GHR, STAT3/5, and downstream-regulated genes in human adipose tissue during diet-induced weight loss and weight gain is lacking.

OBJECTIVE

The aim of the present study was to investigate the gene expression patterns of GHR and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway (JAK2, STAT3, STAT5A, and STAT5B) in human subcutaneous adipose tissue in relation to energy restriction and overfeeding.

DESIGN, PATIENTS, AND INTERVENTIONS

Tissue distribution was analyzed in a data set generated by RNA sequencing containing information on global expression in human tissues. Subcutaneous adipose tissue or adipocyte gene expression (measured by DNA microarrays) was investigated in the following settings: (i) individuals with obesity vs individuals with normal weight; (ii) energy restriction; and (iii) overfeeding.

RESULTS

GHR expression was decreased in subjects with obesity compared with subjects with normal weight (P < 0.001). It was increased in response to energy restriction and decreased in response to overfeeding (P = 0.015 and P = 0.030, respectively). STAT3 expression was increased in subjects with obesity (P < 0.001). It was decreased during energy restriction and increased during overfeeding (P = 0.004 and P = 0.006, respectively). STAT3-regulated genes showed an overall view of overexpression in obesity.

CONCLUSIONS

The results of the present study have shown that GHR, STAT3, and STAT3-regulated genes are dynamically, and reciprocally, regulated at the tissue level in response to energy restriction and overfeeding, suggesting that GH signaling is perturbed in obesity.

Iodine Status After Bariatric Surgery-a Prospective 10-Year Report from the Swedish Obese Subjects (SOS) Study

CONTEXT

Bariatric surgery can lead to nutrient deficiencies. Gastric by-pass (GBP) entails restriction and malabsorption, whereas, vertical banded gastroplasty (VBG) is only restrictive.

OBJECTIVE

The objective of this study is to study whether GBP-patients develop iodine deficiency from malabsorption, and if GBP- and VBG-patients develop lower 24-h urinary iodine excretion (24-UIE) than obese non-operated controls (OB-controls) due to lower iodine intake.

DESIGN

The Swedish Obese Subjects (SOS) study is a prospective, non-randomized study of 4047 obese patients included 1987-2001, who chose bariatric surgery or non-surgical treatment. SOS-groups were compared at baseline, after 2 and 10 years and with population-based subsamples (MONICA-controls).

PATIENTS

One hundred eighty-eight GBP-patients were matched with 188 VBG-patients and 188 OB-controls and with three subgroups from 412 MONICA-controls.

MAIN OUTCOME MEASUREMENTS

Primary outcome was 24-UIE. Secondary outcomes were iodine intake, iodine supplementation, TSH, FT4, and thyroid morbidity.

RESULTS

At baseline, median 24-UIE was higher in GBP-patients, VBG-patients and OB-controls than in MONICA-controls (214, 201, 203 and 137 μg/day, p < 0.001). At 10 years, 24-UIE in GBP-patients (161 μg/day) and VBG-patients (149 μg/day) was lower compared with baseline (p < 0.01) and OB-controls (189 μg/day, p < 0.01), but similar to 24-UIE in MONICA-controls (137 μg/day). The 10-year-dietary iodine intake was similar in GPB-patients and OB-controls, but higher in VBG-patients. Iodine supplementation was taken by 0-9% in SOS-groups.

CONCLUSION

After surgery, GBP- and VBG-patients did not suffer from iodine deficiency, but both groups had lower iodine status than OB-controls. Dietary supplements recommended after bariatric surgery do not need to include iodine, in iodine sufficient countries.

TRIAL REGISTRATION

clinicaltrials.gov : NCT01479452.

Self-Reported Weight-Loss Methods and Weight Change: Ten-Year Analysis in the Swedish Obese Subjects Study Control Group

OBJECTIVE

The Swedish Obese Subjects (SOS) study was designed to compare outcomes in patients with obesity treated by bariatric surgery and a matched control group given usual care. The aim of this study was to analyze self-reported weight-loss methods and weight changes over 10 years in the SOS control group.

METHODS

Self-reported weight-loss methods in the control group (n = 2,037; 71% women; 48.7 ± 6.3 years; BMI 40.1 ± 4.7 kg/m² ) were analyzed at baseline and after 0.5, 1, 2, 3, 4, 6, 8, and 10 years of follow-up and studied in relation to weight changes.

RESULTS

The average 10-year weight change was +2.1% (95% CI: 1.4%-2.8%). At every follow-up, 82.7% (95% CI: 81.3%-84.1%) of participants reported weight-loss attempts. At 10 years, 12.5% of the participants had ≥ 10% weight loss and 22.3% had ≥ 10% weight gain. Participants who lost or gained weight reported similar usage of weight-loss methods.

CONCLUSIONS

Over 10 years, the majority of the participants of the SOS control group reported continuous efforts to lose weight. These results illustrate the constant struggle individuals with severe obesity are facing and that, on average, the results of long-term weight loss and weight maintenance were discouraging.

Long-term incidence of serious fall-related injuries after bariatric surgery in Swedish obese subjects

Obesity increases risk of falling, but the effect of bariatric surgery on fall-related injuries is unknown. The aim of this study was therefore to study the association between bariatric surgery and long-term incidence of fall-related injuries in the prospective, controlled Swedish Obese Subjects study. At inclusion, body mass index was ≥ 34 kg/m² in men and ≥38 kg/m² in women. The surgery per-protocol group (n = 2007) underwent gastric bypass (n = 266), banding (n = 376), or vertical banded gastroplasty (n = 1365), and controls (n = 2040) received usual care. At the time of analysis (31 December 2013), median follow-up was 19 years (maximal 26 years). Fall-related injuries requiring hospital treatment were captured using data from the Swedish National Patient Register. During follow-up, there were 617 first-time fall-related injuries in the surgery group and 513 in the control group (adjusted hazard ratio 1.21, 95% CI, 1.07-1.36; P = 0.002). The incidence differed between treatment groups (P < 0.001, log-rank test) and was higher after gastric bypass than after usual care, banding and vertical banded gastroplasty (adjusted hazard ratio 0.50-0.52, P < 0.001 for all three comparisons). In conclusion, gastric bypass surgery was associated with increased risk of serious fall-related injury requiring hospital treatment.

Lysyl oxidase and adipose tissue dysfunction

BACKGROUND/OBJECTIVES

Lysyl oxidase (LOX) is an enzyme crucial for collagen fibre crosslinking and thus for fibrosis development. Fibrosis is characterised by a surplus of collagen fibre accumulation and is amongst others also a feature of obesity-associated dysfunctional adipose tissue (AT) which has been linked with type 2 diabetes. We hypothesised that in type 2 diabetes and obesity LOX expression and activity will be increased as a consequence of worsening AT dysfunction. This study aimed to provide a comprehensive characterisation of LOX in human AT.

METHODS

LOX mRNA expression was analysed in omental and abdominal subcutaneous AT obtained during elective surgery from subjects with a wide range of BMI, with and without diabetes. In addition, LOX expression was studied in subcutaneous AT before and 9.5months after bariatric surgery. To study the mechanism of LOX changes, its expression and activity were assessed after either hypoxia, recombinant human leptin or glucose treatment of AT explants. In addition, LOX response to acute inflammation was tested after stimulation by a single injection of lipopolysaccharide versus saline solution (control) in healthy men, in vivo. Quantity of mRNA was measured by RT-qPCR.

RESULTS

LOX expression was higher in obesity and correlated with BMI whilst, in vitro, leptin at high concentrations, as a potential feedback mechanism, suppressed its expression. Neither diabetes status, nor hyperglycaemia affected LOX. Hypoxia and lipopolysaccharide-induced acute inflammation increased LOX AT expression, latter was independent of macrophage infiltration.

CONCLUSIONS

Whilst LOX may not be affected by obesity-associated complications such as diabetes, our results confirm that LOX is increased by hypoxia and inflammation as underlying mechanism for its upregulation in adipose tissue with obesity.

MECHANISMS IN ENDOCRINOLOGY: Clinical and pharmacogenetic aspects of the growth hormone receptor polymorphism

Pharmacogenetics aims to maximize the beneficial effects of a medical therapy by identifying genetic finger prints from responders and non-responders and, thereby improving safety and efficacy profile of the drug. Most subjects who are deficient in growth hormone (GHD) are candidates for recombinant human GH (rhGH) therapy. To date, it is well established that even after adjustments for several clinical variables, such as age, gender, body composition and the age at onset of the GHD, response to rhGH treatment is highly variable among individuals, part of which is believed to be due to genetic factors within the GH system. As the first genetic variant to potentially influence the individual response to rhGH therapy in children with growth disorders, polymorphism in the GH receptor (GHR) has attracted a great interest as a target for pharmacogenetics. Studies have been conducted to compare the functional and molecular effects of the full-length GHR (fl-GHR) isoform with the exon 3 deleted (d3-GHR) isoform in children and adults treated with rhGH therapy. Additionally, the impact of the GHR polymorphism has been investigated in relation to the clinical status and response to medical treatment in acromegaly, especially to the GHR antagonist drug pegvisomant. We have performed a narrative review of the studies performed to date on the association of GHR polymorphism with rhGH response in children and adults, and its potential influence in the medical management of acromegaly. In addition, data from studies on the general population and in other chronic diseases examining a role of this genetic variant in the regulation of growth and metabolism are summarized.

Long-term incidence of microvascular disease after bariatric surgery or usual care in patients with obesity, stratified by baseline glycaemic status: a post-hoc analysis of participants from the Swedish Obese Subjects study

BACKGROUND

Bariatric surgery is associated with remission of diabetes and prevention of diabetic complications in patients with obesity and type 2 diabetes. Long-term effects of bariatric surgery on microvascular complications in patients with prediabetes are unknown. The aim of this study was to examine the effects of bariatric surgery on incidence of microvascular complications in patients with obesity stratified by baseline glycaemic status.

METHODS

Patients were recruited to the Swedish Obese Subjects (SOS) study between Sept 1, 1987, and Jan 31, 2001. Inclusion criteria were age 37-60 years and BMI of 34 kg/m² or greater in men and 38 kg/m² or greater in women. Exclusion criteria were identical in surgery and control groups and designed to exclude patients not suitable for surgery. The surgery group (n=2010) underwent gastric bypass (265 [13%]), gastric banding (376 [19%]), or vertical-banded gastroplasty (1369 [68%]). Participants in the control group (n=2037) received usual care. Bodyweight was measured and questionnaires were completed at baseline and at 0·5 years, 1 year, 2 years, 3 years, 4 years, 6 years, 8 years, 10 years, 15 years, and 20 years. Biochemical variables were measured at baseline and at 2 years, 10 years, and 15 years. We categorised participants into subgroups on the basis of baseline glycaemic status (normal [fasting blood glucose concentration <5·0 mmol/L], prediabetes [5·0-6·0 mmol/L], screen-detected diabetes [≥6·1 mmol/L at baseline visit without previous diagnosis], and established diabetes [diagnosis of diabetes before study inclusion]). We obtained data about first incidence of microvascular disease from nationwide registers and about diabetes incidence at study visits at 2 years, 10 years, and 15 years. We did the main analysis by intention to treat, and subgroup analyses after stratification by baseline glycaemic status and by diabetes status at the 15 year follow-up. The SOS study is registered with ClinicalTrials.gov, NCT01479452.

FINDINGS

4032 of the 4047 participants in the SOS study were included in this analysis. We excluded four patients with suspected type 1 diabetes, and 11 patients with unknown glycaemic status at baseline. At baseline, 2838 patients had normal blood glucose, 591 had prediabetes, 246 had screen-detected diabetes, and 357 had established diabetes. Median follow-up was 19 years (IQR 16-21). We identified 374 incident cases of microvascular disease in the control group and 224 in the surgery group (hazard ratio [HR] 0·56, 95% CI 0·48-0·66; p<0·0001). Interaction between baseline glycaemic status and effect of treatment on incidence of microvascular disease was significant (p=0·0003). Unadjusted HRs were lowest in the subgroup with prediabetes (0·18, 95% CI 0·11-0·30), followed by subgroups with screen-detected diabetes (0·39, 0·24-0·65), established diabetes (0·54, 0·40-0·72), and normoglycaemia (0·63, 0·48-0·81). Surgery was associated with reduced incidence of microvascular events in people with prediabetes regardless of whether they developed diabetes during follow-up.

INTERPRETATION

Bariatric surgery was associated with reduced risk of microvascular complications in all subgroups, but the greatest relative risk reduction was observed in patients with prediabetes at baseline. Our results suggest that prediabetes should be treated aggressively to prevent future microvascular events, and effective non-surgical treatments need to be developed for this purpose.

FUNDING

US National Institutes of Health, Swedish Research Council, Sahlgrenska University Hospital Regional Agreement on Medical Education and Research, and Swedish Diabetes Foundation.

Effects of physical activity on the link between PGC-1a and FNDC5 in muscle, circulating Ιrisin and UCP1 of white adipocytes in humans: A systematic review

Background: Exercise may activate a brown adipose-like phenotype in white adipose tissue. The aim of this systematic review was to identify the effects of physical activity on the link between peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1a) and fibronectin type III domain-containing protein 5 (FNDC5) in muscle, circulating Irisin and uncoupling protein one (UCP1) of white adipocytes in humans. Methods: Two databases (PubMed 1966 to 08/2016 and EMBASE 1974 to 08/2016) were searched using an appropriate algorithm. We included articles that examined physical activity and/or exercise in humans that met the following criteria: a) PGC-1a in conjunction with FNDC5 measurements, and b) FNDC5 and/or circulating Irisin and/or UCP1 levels in white adipocytes. Results: We included 51 studies (12 randomised controlled trials) with 2474 participants. Out of the 51 studies, 16 examined PGC-1a and FNDC5 in response to exercise, and only four found increases in both PGC-1a and FNDC5 mRNA and one showed increased FNDC5 mRNA. In total, 22 out of 45 studies that examined circulating Irisin in response to exercise showed increased concentrations when ELISA techniques were used; two studies also revealed increased Irisin levels measured via mass spectrometry. Three studies showed a positive association of circulating Irisin with physical activity levels. One study found no exercise effects on UCP1 mRNA in white adipocytes. Conclusions: The effects of physical activity on the link between PGC-1a, FNDC5 mRNA in muscle and UCP1 in white human adipocytes has attracted little scientific attention. Current methods for Irisin identification lack precision and, therefore, the existing evidence does not allow for conclusions to be made regarding Irisin responses to physical activity. We found a contrast between standardised review methods and accuracy of the measurements used. This should be considered in future systematic reviews.

Effects of physical activity on the link between PGC-1a and FNDC5 in muscle, circulating Ιrisin and UCP1 of white adipocytes in humans: A systematic review

Background: Exercise may activate a brown adipose-like phenotype in white adipose tissue. The aim of this systematic review was to identify the effects of physical activity on the link between peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1a) and fibronectin type III domain-containing protein 5 (FNDC5) in muscle, circulating Irisin and uncoupling protein one (UCP1) of white adipocytes in humans. Methods: Two databases (PubMed 1966 to 08/2016 and EMBASE 1974 to 08/2016) were searched using an appropriate algorithm. We included articles that examined physical activity and/or exercise in humans that met the following criteria: a) PGC-1a in conjunction with FNDC5 measurements, and b) FNDC5 and/or circulating Irisin and/or UCP1 levels in white adipocytes. Results: We included 51 studies (12 randomised controlled trials) with 2474 participants. Out of the 51 studies, 16 examined PGC-1a and FNDC5 in response to exercise, and only four found increases in both PGC-1a and FNDC5 mRNA and one showed increased FNDC5 mRNA. In total, 22 out of 45 studies that examined circulating Irisin in response to exercise showed increased concentrations when ELISA techniques were used; two studies also revealed increased Irisin levels measured via mass spectrometry. Three studies showed a positive association of circulating Irisin with physical activity levels. One study found no exercise effects on UCP1 mRNA in white adipocytes. Conclusions: The effects of physical activity on the link between PGC-1a, FNDC5 mRNA in muscle and UCP1 in white human adipocytes has attracted little scientific attention. Current methods for Irisin identification lack precision and, therefore, the existing evidence does not allow for conclusions to be made regarding Irisin responses to physical activity. We found a contrast between standardised review methods and accuracy of the measurements used. This should be considered in future systematic reviews.

Long-term incidence of female-specific cancer after bariatric surgery or usual care in the Swedish Obese Subjects Study

OBJECTIVE

To examine the long-term effects of bariatric surgery on female-specific cancer in women with obesity.

METHODS

The prospective, matched Swedish Obese Subjects (SOS) study was designed to examine outcomes after bariatric surgery. This study includes 1420 women from the SOS cohort that underwent bariatric surgery and 1447 contemporaneously matched controls who received conventional obesity treatment. Age was 37-60years and BMI was ≥38kg/m². Information on cancer events was obtained from the Swedish National Cancer Registry. Median follow-up time was 18.1years (interquartile range 14.8-20.9years, maximum 26years). This study is registered with ClinicalTrials.gov, NCT01479452.

RESULTS

Bariatric surgery was associated with reduced risk of overall cancer (hazard ratio=0.71; 95% CI 0.59-0.85; p<0.001). About half of the observed cancers were female-specific, and the incidence of these were lower in the surgery group compared with the control group (hazard ratio=0.68; 95% CI 0.52-0·88; p=0.004). The surgical treatment benefit with respect to female-specific cancer was significantly associated with baseline serum insulin (interaction p value=0.022), with greater relative treatment benefit in patients with medium or high insulin levels. Separate analyses of different types of female-specific cancers showed that bariatric surgery was associated with reduced risk of endometrial cancer (hazard ratio=0.56: 95% CI 0.35-0.89; p=0.014).

CONCLUSIONS

In this long-term study, bariatric surgery was associated with reduced risk of female-specific cancer, especially in women with hyperinsulinemia at baseline.

FUNDING

This project was supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under Award Number R01DK105948 (the content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health), the Swedish Research Council K2013-99X-22279-01, K2013-54X-11285-19, Sahlgrenska University Hospital ALF research grant and Swedish Diabetes Foundation.

Microdialysis and proteomics of subcutaneous interstitial fluid reveals increased galectin-1 in type 2 diabetes patients

OBJECTIVE

To identify a potential therapeutic target for type 2 diabetes by comparing the subcutaneous interstitial fluid from type 2 diabetes patients and healthy men.

METHODS

Proteomics was performed on the interstitial fluid of subcutaneous adipose tissue obtained by microdialysis from 7 type 2 diabetes patients and 8 healthy participants. 851 proteins were detected, of which 36 (including galectin-1) showed significantly altered expression in type 2 diabetes. We also measured galectin-1 expression in: (1) adipocytes isolated from adipose tissue biopsies from these participants; (2) subcutaneous adipose tissue of 24 obese participants before, during and after 16weeks on a very low calorie diet (VLCD); and (3) adipocytes isolated from 6 healthy young participants after 4weeks on a diet and lifestyle intervention to promote weight gain. We also determined the effect of galectin-1 on glucose uptake in human adipose tissue.

RESULTS

Galectin-1 protein levels were elevated in subcutaneous dialysates from type 2 diabetes compared with healthy controls (p<0.05). In agreement, galectin-1 mRNA expression was increased in adipocytes from the type 2 diabetes patients (p<0.05). Furthermore, galectin-1 mRNA expression was decreased in adipose tissue after VLCD (p<0.05) and increased by overfeeding (p<0.05). Co-incubation of isolated human adipocytes with galectin-1 reduced glucose uptake (p<0.05) but this was independent of the insulin signal.

CONCLUSION

Proteomics of the interstitial fluid in subcutaneous adipose tissue in vivo identified a novel adipokine, galectin-1, with a potential role in the pathophysiology of type 2 diabetes.

Normalization of qPCR in platelets - YWHAE a potential genericreference gene

The mRNA of human platelets has been extensively studied and it is generally appreciated that platelets contain mRNA transcripts derived from the megakaryocytes, and they have the ability to translate it into proteins. Additionally, platelets contain microRNA (miRNA) that has been shown to potentially regulate the translation of certain proteins. When quantifying gene expression by quantitative real-time polymerase chain reaction (qPCR), a valid normalization method is required and the use of reference genes is a common and robust approach. It is recommended to perform a proper validation of potential reference genes for each individual experimental setup. Previous studies have mainly been performed using commonly used reference genes for nucleated cells, and to our knowledge there are no global evaluations of the stability of transcripts in platelets. Finding a stable transcript would be valuable for inter-study comparisons, and the aim of this study was to identify one or more stable mRNA transcripts suitable as generic reference genes for mRNA gene expression studies in platelets. Platelets were incubated for 24 h and microarray of platelet mRNA revealed that the levels of YWHAE, B2M, ITM2B, H3F3A, PF4V1 remained similar between 0 and 24 h. Further validation of the stability of these genes together with GAPDH, RN18S1, and PPIA, genes frequently used as reference genes in platelet studies, was performed using qPCR after different in vitro conditions. In addition, inter-individual stability of the genes was analyzed in diabetic patients compared with healthy matched controls. Analysis of gene stability by the software RefFinder revealed that YWHAE, PF4V1, and B2M were the most stable genes in platelets from healthy donors. In addition, YWHAE was stable between subjects. Furthermore, the potential influence of miRNA on the selected genes was investigated by knockdown of Dicer1 in the megakaryocytic cell line MEG01. YWHAE, H3F3A, B2M, and GAPDH remained unchanged over time in MEG01 cells indicating that these genes are not regulated by miRNA and hence are more stably expressed. In conclusion, YWHAE is a stable transcript in platelets and we suggest the use of YWHAE as a generic reference gene in mRNA gene expression studies.

Chronic l-menthol-induced browning of white adipose tissue hypothesis: A putative therapeutic regime for combating obesity and improving metabolic health

INTRODUCTION

Obesity constitutes a serious global health concern reaching pandemic prevalence rates. The existence of functional brown adipose tissue (BAT) in adult humans has provoked intense research interest in the role of this metabolically active tissue in whole-body energy balance and body weight regulation. A number of environmental, physiological, pathological, and pharmacological stimuli have been proposed to induce BAT-mediated thermogenesis and functional thermogenic BAT-like activity in white adipose tissue (WAT), opening new avenues for therapeutic strategies based on enhancing the number of beige adipocytes in WAT.

HYPOTHESIS

Recent evidence support a role of l-menthol cooling, mediated by TRPM8 receptor, on UCP1-dependent thermogenesis and BAT-like activity in classical WAT depots along with the recruitment of BAT at specific anatomical sites. l-Menthol-induced BAT thermogenesis has been suggested to occur by a β-adrenergic-independent mechanism, avoiding potential side-effects due to extensive β-adrenergic stimulation mediated by available beta receptor agonists. l-Menthol has been also linked to the activation of the cold-gated ion channel TRPA1. However, its role in l-menthol-induced UCP1-dependent thermogenic activity in BAT and WAT remains undetermined. White adipose tissue plasticity has important clinical implications for obesity prevention and/or treatment because higher levels of UCP1-dependent thermogenesis can lead to enhanced energy expenditure at a considerable extent. We hypothesize that chronic dietary l-menthol treatment could induce TRPM8- and TRPA1-dependent WAT adaptations, resembling BAT-like activity, and overall improve whole-body metabolic health in obese and overweight individuals.

CONCLUSIONS

The putative impact of chronic l-menthol dietary treatment on the stimulation of BAT-like activity in classical WAT depots in humans remains unknown. A detailed experimental design has been proposed to investigate the hypothesized l-menthol-induced browning of WAT. If our hypothesis was to be confirmed, TRPM8/TRPA1-induced metabolic adaptations of WAT to BAT-like activity could provide a promising novel therapeutic approach for increasing energy expenditure, regulating body weight, and preventing obesity and its related co-morbidities in humans.

Thermogenic activity of UCP1 in human white fat-derived beige adipocytes

Heat-producing beige/brite (brown-in-white) adipocytes in white adipose tissue have the potential to suppress metabolic disease in mice and hold great promise for the treatment of obesity and type 2 diabetes in humans. Here, we demonstrate that human adipose-derived stromal/progenitor cells (hASCs) from subcutaneous white adipose tissue can be efficiently converted into beige adipocytes. Upon pharmacological activation of peroxisome proliferator-activated receptor-γ, hASC-derived adipocytes activated beige fat-selective genes and a brown/beige fat-selective electron transport chain gene program. Importantly, hASC-derived beige fat cells displayed the bioenergetic characteristics of genuine brown fat cells, including a capacity for increased respiratory uncoupling in response to β-adrenergic agonists. Furthermore, knock-down experiments reveal that the thermogenic capacity of human beige fat cells was entirely dependent on the presence of Uncoupling protein 1. In summary, this study reveals that hASCs can be readily differentiated into beige adipocytes that, upon activation, undergo uncoupling protein 1-dependent thermogenesis.

Evaluation of reference genes for gene expression studies in human brown adipose tissue

Human brown adipose tissue (BAT) has during the last 5 year been subjected to an increasing research interest, due to its putative function as a target for future obesity treatments. The most commonly used method for molecular studies of human BAT is the quantitative polymerase chain reaction (qPCR). This method requires normalization to a reference gene (genes with uniform expression under different experimental conditions, e.g. similar expression levels between human BAT and WAT), but so far no evaluation of reference genes for human BAT has been performed. Two different microarray datasets with samples containing human BAT were used to search for genes with low variability in expression levels. Seven genes (FAM96B, GNB1, GNB2, HUWE1, PSMB2, RING1 and TPT1) identified by microarray analysis, and 8 commonly used reference genes (18S, B2M, GAPDH, LRP10, PPIA, RPLP0, UBC, and YWHAZ) were selected and further analyzed by quantitative PCR in both BAT containing perirenal adipose tissue and subcutaneous adipose tissue. Results were analyzed using 2 different algorithms (Normfinder and geNorm). Most of the commonly used reference genes displayed acceptably low variability (geNorm M-values <0.5) in the samples analyzed, but the novel reference genes identified by microarray displayed an even lower variability (M-values <0.25). Our data suggests that PSMB2, GNB2 and GNB1 are suitable novel reference genes for qPCR analysis of human BAT and we recommend that they are included in future gene expression studies of human BAT.

FTO Obesity Variant Circuitry and Adipocyte Browning in Humans

BACKGROUND

Genomewide association studies can be used to identify disease-relevant genomic regions, but interpretation of the data is challenging. The FTO region harbors the strongest genetic association with obesity, yet the mechanistic basis of this association remains elusive.

METHODS

We examined epigenomic data, allelic activity, motif conservation, regulator expression, and gene coexpression patterns, with the aim of dissecting the regulatory circuitry and mechanistic basis of the association between the FTO region and obesity. We validated our predictions with the use of directed perturbations in samples from patients and from mice and with endogenous CRISPR-Cas9 genome editing in samples from patients.

RESULTS

Our data indicate that the FTO allele associated with obesity represses mitochondrial thermogenesis in adipocyte precursor cells in a tissue-autonomous manner. The rs1421085 T-to-C single-nucleotide variant disrupts a conserved motif for the ARID5B repressor, which leads to derepression of a potent preadipocyte enhancer and a doubling of IRX3 and IRX5 expression during early adipocyte differentiation. This results in a cell-autonomous developmental shift from energy-dissipating beige (brite) adipocytes to energy-storing white adipocytes, with a reduction in mitochondrial thermogenesis by a factor of 5, as well as an increase in lipid storage. Inhibition of Irx3 in adipose tissue in mice reduced body weight and increased energy dissipation without a change in physical activity or appetite. Knockdown of IRX3 or IRX5 in primary adipocytes from participants with the risk allele restored thermogenesis, increasing it by a factor of 7, and overexpression of these genes had the opposite effect in adipocytes from nonrisk-allele carriers. Repair of the ARID5B motif by CRISPR-Cas9 editing of rs1421085 in primary adipocytes from a patient with the risk allele restored IRX3 and IRX5 repression, activated browning expression programs, and restored thermogenesis, increasing it by a factor of 7.

CONCLUSIONS

Our results point to a pathway for adipocyte thermogenesis regulation involving ARID5B, rs1421085, IRX3, and IRX5, which, when manipulated, had pronounced pro-obesity and anti-obesity effects. (Funded by the German Research Center for Environmental Health and others.).

Bacterial contamination of suction catheter tips during aortic valve replacement surgery: a prospective observational cohort study

Background

Bacterial mediastinitis is a severe complication after open heart surgery. The infection causes prolonged hospitalization and an increased mortality risk. Observations from orthopaedic surgery showed that the suction catheter used during surgery is commonly contaminated with bacteria. The aim of this study was to describe the prevalence of suction catheter contamination in cardiac surgery and to study if suction time influences the contamination risk.

Methods

Fifty suction catheter tips were collected during 25 aortic valve replacement operations. The suction tip was exchanged once during the operation (after aortotomy closure). The tips were subjected to bacterial contamination analysis.

Results

In 20 of the 25 investigated cases (80%), bacterial contamination was detected on one or both tips. The tip used during the beginning of the operation showed bacterial contamination in 13/25 cases (52%) and the second tip in 12/25 (48%). In 5/25 cases (20%) both tips were contaminated. There was no association between bacterial contamination and suction time. Coagulase-negative staphylococcus was the most commonly detected microorganism.

Conclusions

The suction device should be considered as a potential source of bacterial contamination in cardiac surgery. The results suggest that the suction catheter should be replaced before key moments like valve implantation and sternal closure.

BMP4 and BMP Antagonists Regulate Human White and Beige Adipogenesis

The limited expandability of subcutaneous adipose tissue, due to reduced ability to recruit and differentiate new adipocytes, prevents its buffering effect in obesity and is characterized by expanded adipocytes (hypertrophic obesity). Bone morphogenetic protein-4 (BMP4) plays a key role in regulating adipogenic precursor cell commitment and differentiation. We found BMP4 to be induced and secreted by differentiated (pre)adipocytes, and BMP4 was increased in large adipose cells. However, the precursor cells exhibited a resistance to BMP4 owing to increased secretion of the BMP inhibitor Gremlin-1 (GREM1). GREM1 is secreted by (pre)adipocytes and is an inhibitor of both BMP4 and BMP7. BMP4 alone, and/or silencing GREM1, increased transcriptional activation of peroxisome proliferator-activated receptor γ and promoted the preadipocytes to assume an oxidative beige/brown adipose phenotype including markers of increased mitochondria and PGC1α. Driving white adipose differentiation inhibited the beige/brown markers, suggesting the presence of multipotent adipogenic precursor cells. However, silencing GREM1 and/or adding BMP4 during white adipogenic differentiation reactivated beige/brown markers, suggesting that increased BMP4 preferentially regulates the beige/brown phenotype. Thus, BMP4, secreted by white adipose cells, is an integral feedback regulator of both white and beige adipogenic commitment and differentiation, and resistance to BMP4 by GREM1 characterizes hypertrophic obesity.

The GH receptor exon 3 deleted/full-length polymorphism is associated with central adiposity in the general population

OBJECTIVE

To test the hypothesis that the GH receptor (GHR) exon 3 deleted (d3)/full-length (fl) polymorphism influences anthropometry and body composition in the general population.

DESIGN AND SETTING

The Swedish Obese Subjects (SOS) reference study is a cross-sectional population-based study, randomly selected from a population registry. A subgroup of the population-based Malmö Diet and Cancer study (MDC-CC) was used as a replication cohort.

METHODS

The SOS reference study comprises 1135 subjects (46.2% men), with an average age of 49.5 years. The MDC-CC includes 5451 successfully genotyped subjects (41.5% men), with an average age of 57.5 years. GHR d3/fl genotypes were determined using TagSNP rs6873545. Linear regression analyses were used to test for genotype-phenotype associations.

RESULTS

In the SOS reference study, subjects homozygous for the d3-GHR weighed ∼4 kg more (P=0.011), and had larger waist-to-hip ratio (WHR, P=0.036), larger waist circumference (P=0.016), and more fat-free mass estimated from total body potassium (P=0.026) than grouped fl/d3 and fl/fl subjects (d3-recessive genetic model). The association with WHR was replicated in the MDC-CC (P=0.002), but not those with other anthropometric traits.

CONCLUSIONS

In this population-based study, the GHR d3/fl polymorphism was found to be of functional relevance and associated with central adiposity, such that subjects homozygous for the d3-GHR showed an increased abdominal obesity.

Differentiation of human induced pluripotent stem cells into brown and white adipocytes: role of Pax3

Identification of molecular mechanisms involved in generation of different types of adipocytes is progressing substantially in mice. However, much less is known regarding characterization of brown (BAP) and white adipocyte progenitors (WAPs) in humans, highlighting the need for an in vitro model of human adipocyte development. Here, we report a procedure to selectively derive BAP and WAPs from human-induced pluripotent stem cells. Molecular characterization of APs of both phenotypes revealed that BMP4, Hox8, Hoxc9, and HoxA5 genes were specifically expressed in WAPs, whereas expression of PRDM16, Dio2, and Pax3 marked BAPs. We focused on Pax3 and we showed that expression of this transcription factor was enriched in human perirenal white adipose tissue samples expressing UCP1 and in human classical brown fat. Finally, functional experiments indicated that Pax3 was a critical player of human AP fate as its ectopic expression led to convert WAPs into brown-like APs. Together, these data support a model in which Pax3 is a new marker of human BAPs and a molecular mediator of their fate. The findings of this study could lead to new anti-obesity therapies based on the recruitment of APs and constitute a platform for investigating in vitro the developmental origins of human white and brown adipocytes.