A multilocus genetic risk score for obesity: Association with BMI and metabolic alterations in a cohort with severe obesity.

Genome wide association studies have identified numerous single nucleotide polymorphisms (SNPs) associated with obesity, yet effect sizes of individual SNPs are small. Therefore, the aim of our study was to investigate whether a genetic risk score (GRS) comprising risk alleles of SNPs identified in the GIANT consortium meta-analyses shows association with body mass index (BMI) and other BMI related metabolic alterations in a cohort with an extreme phenotype. Genotyping of 93 SNPs was performed in 314 obese individuals (mean BMI 40.5 ± 7.8 kg/m², aged 45 ± 12 years), participating in a standardized weight reduction program, and in 74 lean controls (mean BMI 24.6 ± 3.3 kg/m², aged 41.7 ± 13.4 years). Allele numbers of all 93 SNPs were added to a GRS. Anthropometric parameters, parameters of glucose/insulin and lipid metabolism were assessed standardized after a 12 hours fast. GRS was significantly different between controls and obese individuals (unweighted GRS: 86.6 vs 89.0, P = .002; weighted GRS: 84.9 vs 88.3, P = .005). Furthermore, linear regression analysis showed significant associations of GRS with BMI ( P < .0001), weight ( P = .0005), waist circumference ( P = .0039), fat mass ( P < .0001) and epicardial fat thickness ( P = .0032), yet with small effect sizes ( r ² < 0.06). In conclusion, in our study GRS could differentiate between extreme obese and lean individuals, and was associated with BMI and its related traits, yet with small effect sizes.

Improvement of obstructive sleep apnea does not rescue left atrial enlargement in obese participants of a multimodal weight reduction program.

The aim of our study was to investigate the effect of obstructive sleep apnea (OSA) and its weight loss related improvement on left atrial (LA) area in individuals with severe obesity participating in a multimodal weight reduction (WR) program. Participants with obesity (body mass index, BMI, 40.2 ± 7.3 kg/m2) underwent a 1-year WR program. Phenotyping was performed at baseline and after 12 months. Individuals were categorized according to their baseline apnea-hypopnea-index (AHI) into "no OSA" (AHI < 5) and "OSA" (AHI ≥ 5). From a total of 84 study participants, 69 completed the program. Average WR was 19.0 ± 15.7 kg after 12 months. Participants with obesity and OSA had a larger LA area at baseline as compared to participants with obesity but without OSA (22.4 ± 5.6 vs 18.8 ± 3.8 cm2; P = .008). Linear regression showed significant associations of AHI and BMI with LA area. In contrast, despite a significant decrease of AHI in participants with OSA as compared to those without OSA at 1 year follow up (ΔAHI was -12 ± 14) ΔLA area did not significantly differ between groups. Multivariable linear regression showed no significant association of ΔAHI or ΔBMI with ΔLA. In conclusion, the presence of obstructive sleep apnea contributes to LA enlargement on top of obesity in our study cohort. Yet, successful WR with subsequently improved OSA was not associated with an improvement of LA area.

Gender differences in cardiometabolic health and disease in a cross-sectional observational obesity study.

BACKGROUND: Beyond the degree of adiposity, the pattern of fat distribution has a profound influence on cardiometabolic risk. It is unclear if sex differences in body fat distribution can potentially explain any sex differences in the prevalence of the metabolic syndrome (MetS) and in individual cardiometabolic risk factors among obese men and women. METHODS: In this cross-sectional analysis, 432 persons from the ongoing Obesity Weight Reduction Study (n = 356 obese, ØBMI 41 ± 8 kg/m2, and 76 non-obese, ØBMI 25 ± 3 kg/m2), were included. The relations of sex to MetS prevalence and selected cardiometabolic risk factors were assessed using univariate and multivariate adjusted regression models. RESULTS: In crude analyses, %fat mass and the fat mass/lean mass ratio were significantly higher in women than in men, regardless of increasing obesity categories, from normal weight to grade-3-obesity. In contrast, markers of abdominal obesity, such as waist circumference and waist-to-hip ratio were higher in men than in women, despite similar BMI. The prevalence of the MetS was higher in obese men than in women (67.6 vs. 45.0%, p < 0.0001), particularly in younger individuals < 40 years (72.5 vs. 36.8%, p < 0.0001), but "metabolically healthy obesity" (BMI ≥ 30, no other NCEP ATPIII MetS component) was more common in women than in men (15.6 vs. 4.1%, p < 0.0001). After adjusting for age, %body fat and height, sex differences were observed for HDL-cholesterol (p < 0.001), triglycerides (p < 0.001), fasting glucose (p = 0.002), insulin and HOMA-IR levels (p < 0.001), ALAT (p < 0.001), adiponectin (p < 0.001), and sE-selectin (p = 0.005). In contrast, crude sex differences in other variables, such as leptin levels (68 ± 4 in obese women vs. 33 ± 2 µg/L in men, p < 0.0001), disappeared after accounting for differences in %body fat (least-squares means of leptin: 52 ± 4 vs. 55 ± 6 µg /L, p = 0.740). A logistic regression model adjusting for age and lifestyle factors revealed a lower risk of having MetS for women as compared to men (OR = 0.38[0.22-0.60]). That risk estimate did not materially alter after adding BMI to the model. In contrast, no statistically significant association between sex and MetS prevalence was observed after adding waist circumference and adiponectin to the model (OR = 1.41[0.59-3.36]). CONCLUSIONS: Different body fat distribution patterns, particularly abdominal adiposity, adiponectin, and related biomarkers, may contribute to sex differences in cardiometabolic risk factors and to the prevalence of the MetS.

Successful weight loss reduces endothelial activation in individuals with severe obesity participating in a multimodal weight loss program.

INTRODUCTION: Endothelial dysfunction is a very common finding in obesity and metabolic syndrome. The aim of our study was to investigate if longterm weight reduction (WR) success may reverse endothelial activation in individuals with severe obesity participating in a multimodal WR program. METHODS: Participants with obesity (øBMI 40.3 ±7.5 kg/m2) underwent a standardized non-surgical 1-year WR program. Carotid artery studies and determination of endothelial function biomarkers were performed at baseline and after 1 year. Individuals were dichotomized in "successful WR" (% WR≥10% of initial body weight) and "failed WR" (% WR<10% of initial body weight). RESULTS: From 191 people with obesity, 115 achieved successful WR. Compared to controls without obesity (n=44) participants with obesity had higher carotid intima media thickness as well as higher sICAM-1, sE-selectin, MMP-9, hsCRP and IL-6 levels. After 12 months follow up delta values of inflammation and endothelial adhesion markers were significantly different between participants with obesity and successful WR and participants with obesity and failed WR, in favour of the successful WR group (mean ± standard deviation): ΔhsCRP (-5.2 mg/L ±7.8 vs. 1.1 mg/L ±5.1, P<0.001; Padj=0.009), ΔIL-6 (-1.0 pg/mL ±3.4 vs. 0.5 pg/mL ±2.6, P<0.001; Padj=0.057), ΔsE-selectin (-19.0 ng/mL ±24.4 vs. 39.2 ng/mL ±20.3, P<0.001; Padj<0.001), ΔsICAM-1 (-26.4 ng/mL ±68.8 vs. 10.6 ng/mL ±73.9, P=0.004; Padj=0.805) and ΔoxLDL (-4 mg/dL ±30 vs. 5 mg/dL ±25, P=0.004; Padj=0.473). In linear regression analysis reduction of BMI was significantly associated with improvement of several endothelial dysfunction biomarkers with the strongest effects for ΔsE-selectin and ΔhsCRP. CONCLUSION: Our data corroborate the finding that obesity leads to endothelial dysfunction. Furthermore, successful non-surgical WR may at least partially reverse endothelial activation implicating cardiovascular health benefits of WR in people with severe obesity.

The adipo-fibrokine activin A is associated with metabolic abnormalities and left ventricular diastolic dysfunction in obese patients.

AIMS: Left ventricular diastolic dysfunction (LVDD) is common in obese subjects, and a relationship between epicardial adipose tissue (EAT), increased adipocytokines, and cardiovascular diseases has been reported. This study sought to examine as to whether the adipo-fibrokine activin A is a link between increased EAT, the metabolic syndrome (MetS), and LVDD in severely obese subjects. METHODS AND RESULTS: In 236 obese subjects (ø body mass index 39.8 ± 7.9 kg/m2 ) with a variable degree of the MetS and in 60 healthy non-obese controls (ø body mass index 24.8 ± 3.4 kg/m2 ), serum activin A levels were measured and correlated with parameters of the MetS, epicardial fat thickness (EFT), and echocardiographic parameters of LVDD. Activin A levels were higher in obese than in non-obese subjects (362 ± 124 vs. 301 ± 94 pg/mL, P = 0.0004), increased with the number of MetS components (from 285 ± 82 with no MetS component, 323 ± 94 with one or two MetS components, to 403 ± 131 pg/mL with ≥3 MetS components, P < 0.0001) and correlated with EFT (r = 0.41, P < 0.001). Furthermore, activin A levels were related to several parameters of LVDD [e.g. left atrial size (382 ± 117 vs. 352 125 pg/mL, P = 0.024), E/e' (394 ± 108 vs. 356 ± 127 pg/mL, P = 0.005)]. LVDD was highest in MetS obese subjects with high EFT (44.3%) compared with MetS obese subjects with low EFT (27.0%), non-MetS obese subjects with high EFT (24.2%), and non-MetS obese subjects with low EFT (10.6%, P < 0.0001). CONCLUSIONS: In severe obesity, activin A was significantly related to EFT, MetS, and LVDD, implicating MetS-related alterations in the secretory profile of EAT in the pathogenesis of obesity-related heart disease.

Relation Between Obesity, Metabolic Syndrome, Successful Long-Term Weight Reduction, and Right Ventricular Function.

This study sought to examine the relationships between right ventricular (RV) function and geometry, morbid obesity with and without the metabolic syndrome, and the effect of long-term weight loss. Obese (n = 153, BMI 41.2 ± 8.7 kg/m(2)) and healthy non-obese control subjects (n = 38, BMI 25.5 ± 3.3 kg/m(2)) of similar age and gender distribution were prospectively studied during the course of a 1-year weight reduction program with echocardiography at baseline and after one year of follow up. Function and geometry of the right heart were evaluated by tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (TDI S'), RV myocardial performance index (TEI), RV end-diastolic (RVEDD) and end-systolic diameter (RVESD), area of the right atrium (RAA), and systolic pulmonary artery pressure (PAP). Whereas parameters of systolic and diastolic LV function were significantly worse in the obese subjects than those in the non-obese subjects (EF 66 ± 6 versus 69 ± 6%, P = 0.004; E/E' 7.4 ± 2.5 versus 6.3 ± 2.6, P = 0.010), parameters of RV function (TAPSE 25.6 ± 4.5 versus 25.1 ± 3.5 mm, P = 0.528; TDI S' 13.5 ± 2.9 versus 13.8 ± 2.9 mm/second, P = 0.553; TEI 0.25 ± 0.13 versus 0.28 ± 0.09, P = 0.283) as well as geometry measurements were comparable between the obese and non-obese participants and also in obese subjects with full blown metabolic syndrome. Additionally, successful weight reduction did not alter the RV parameters. Nevertheless, in the few obese subjects with RV dysfunction (n = 7), metabolic syndrome parameters were more pronounced than in obese with normal RV function.Morbid obesity with and without the metabolic syndrome is accompanied by an impaired LV systolic and diastolic function. In contrast, RV function appears to be less affected by obesity independent of the presence of the metabolic syndrome.