Paradoxical preservation of vascular function in severe obesity

Body mass index, waist circumference, and mortality in subjects older than 80 years: a Mendelian randomization study

BACKGROUND AND AIMS

Emerging evidence has raised an obesity paradox in observational studies of body mass index (BMI) and health among the oldest-old (aged ≥80 years), as an inverse relationship of BMI with mortality was reported. This study was to investigate the causal associations of BMI, waist circumference (WC), or both with mortality in the oldest-old people in China.

METHODS

A total of 5306 community-based oldest-old (mean age 90.6 years) were enrolled in the Chinese Longitudinal Healthy Longevity Survey (CLHLS) between 1998 and 2018. Genetic risk scores were constructed from 58 single-nucleotide polymorphisms (SNPs) associated with BMI and 49 SNPs associated with WC to subsequently derive causal estimates for Mendelian randomization (MR) models. One-sample linear MR along with non-linear MR analyses were performed to explore the associations of genetically predicted BMI, WC, and their joint effect with all-cause mortality, cardiovascular disease (CVD) mortality, and non-CVD mortality.

RESULTS

During 24 337 person-years of follow-up, 3766 deaths were documented. In observational analyses, higher BMI and WC were both associated with decreased mortality risk [hazard ratio (HR) 0.963, 95% confidence interval (CI) 0.955-0.971 for a 1-kg/m2 increment of BMI and HR 0.971 (95% CI 0.950-0.993) for each 5 cm increase of WC]. Linear MR models indicated that each 1 kg/m2 increase in genetically predicted BMI was monotonically associated with a 4.5% decrease in all-cause mortality risk [HR 0.955 (95% CI 0.928-0.983)]. Non-linear curves showed the lowest mortality risk at the BMI of around 28.0 kg/m2, suggesting that optimal BMI for the oldest-old may be around overweight or mild obesity. Positive monotonic causal associations were observed between WC and all-cause mortality [HR 1.108 (95% CI 1.036-1.185) per 5 cm increase], CVD mortality [HR 1.193 (95% CI 1.064-1.337)], and non-CVD mortality [HR 1.110 (95% CI 1.016-1.212)]. The joint effect analyses indicated that the lowest risk was observed among those with higher BMI and lower WC.

CONCLUSIONS

Among the oldest-old, opposite causal associations of BMI and WC with mortality were observed, and a body figure with higher BMI and lower WC could substantially decrease the mortality risk. Guidelines for the weight management should be cautiously designed and implemented among the oldest-old people, considering distinct roles of BMI and WC.

PET/CT Assessment of Flow-Mediated Epicardial Vasodilation in Obesity and Severe Obesity

Background

It is not known whether the transition from obesity and severe obesity, as 2 different metabolic disease entities, affect flow-mediated and, thus, endothelium-dependent epicardial vasodilation.

Objectives

The purpose of this study was to investigate the effect of obesity and severe obesity on flow-mediated epicardial vasomotion with positron emission tomography/computed tomography-determined longitudinal decrease in myocardial blood flow (MBF) from the base-to-apex direction of the left ventricle or gradient.

Methods

13N-ammonia positron emission tomography/computed tomography evaluated global MBF during pharmacologically induced hyperemia and at rest for assessment of coronary microvascular function. In addition, the Δ longitudinal MBF gradient (hyperemia minus rest) was determined. Patients were then grouped according to the body mass index (BMI) into normal weight (NW) (BMI 20.0-24.9 kg/m2, n = 27), overweight (OW) (BMI 25.0-29.9 kg/m2, n = 29), obesity (OB) (BMI 30.0-39.9 kg/m2, n = 53), and severe obesity (morbid obesity: BMI ≥40 kg/m2, n = 43).

Results

Compared to NW, left ventricular Δ longitudinal MBF gradient progressively declined in OW and OB (0.04 ± 0.09 mL/g/min vs -0.11 ± 0.14 mL/g/min and -0.15 ± 0.11 mL/g/min; P ≤ 0.001, respectively) but not significantly in SOB (-0.01 ± 0.11 mL/g/min, P = 0.066). Regadenoson-induced global hyperemic MBF was lower in OB than in NW (1.88 ± 0.40 mL/g/min vs 2.35 ± 0.32 mL/g/min; P ≤ 0.001), while comparable between NW and SOB (2.35 ± 0.32 mL/g/min vs 2.26 ± 0.40 mL/g/min; P = 0.302). The BMI of the study population was associated with the Δ longitudinal MBF gradient in a U-turn fashion (r = 0.362, standard error of the estimate = 0.124; P < 0.001).

Conclusions

Increased body weight associates with abnormalities in coronary circulatory function that advances from an impairment flow-mediated, epicardial vasodilation in overweight and obesity to coronary microvascular dysfunction in obesity, not observed in severe obesity. The U-turn of flow-mediated epicardial vasomotion outlines obesity and severe obesity to affect epicardial endothelial function differently.

Exploring the Diversity of Visceral, Subcutaneous and Perivascular Adipose Tissue in a Vascular Surgery Population

The prevalence of obesity has doubled, with a concomitant increase in cardiovascular disease. This study aimed to compare the characteristics of visceral, subcutaneous and peri-aortic adipose tissue determined with computed tomography (CT) scans and to correlate them with cardiovascular risk factors, anthropometric measures and medication. An observational and prospective study was conducted, and 177 subjects were included. Peri-aortic adipose tissue had the highest density, while the subcutaneous adipose tissue had the lowest. The density of subcutaneous adipose tissue differs from the density of visceral (p = 0.00) and peri-aortic adipose tissue (p = 0.00). Smokers/ex-smokers had a lower area (p = 0.00) and density (p = 0.02) of subcutaneous adipose tissue. Multiple linear regression analysis showed that sex was a predictor of subcutaneous adipose tissue area (β = -0.27, t = -3.12, p = 0.00) but smoking habits were not. After controlling for sex, we found that the association between smokers/ex-smokers and area of subcutaneous adipose tissue was lost, but the association with density persisted. Patients with hypertension had a higher visceral adipose tissue area, and this relationship was maintained even after adjusting for gender. Peri-aortic adipose tissue is similar to visceral and distinct from subcutaneous adipose tissue. Cardiovascular risk factors have different influences in distinct adipose compartments.

Obesity and risk of hearing loss in the middle-aged and elderly: a national cohort of Chinese adults

BACKGROUND

The relationship between obesity and hearing loss among the middle-aged and older population remained unclear. Moreover, few studies have focused on the impact of gender on this association.

METHODS

This cohort study extracted the data from the China Health and Retirement Longitudinal Study, a national survey of adults aged 45 years or over. Waist circumference was categorized into three groups: normal, pre-central obesity, and central obesity. We classified BMI into four categories: underweight, normal weight, overweight, and obese. The primary endpoint was the incidence of self-reported hearing loss.

RESULTS

Of the 14,237 participants, 1972 incidents of hearing loss were identified during a median 6.9 years of follow-up. The cumulative incidence of hearing loss was 13.9% (95% CI 13.3% -14.4%). Our study showed that central obesity was significantly associated with hearing loss (HR 0.84, 95%CI 0.75-0.94), and this relationship was more prominent in males (HR 0.76, 95%CI 0.63-0.91). Among male participants, the underweight group was at the highest risk of hearing loss (HR 1.39, 95%CI 1.08-1.79). Compared with the normal weight group, the adjusted HR for hearing loss in the obese groups was 0.69 (95%CI 0.51-0.94) among men. Among female participants, only the overweight group had a lower risk of hearing loss than the normal weight group (HR 0.83, 95%CI 0.71-0.96).

CONCLUSIONS

Being overweight and obese were significantly associated with a decreased risk of hearing loss, whereas being underweight was associated with an increased risk of hearing loss.

Association of body mass index with survival in U.S. cancer survivors: a cross-sectional study of NHANES 1999-2018

Background

Understanding the association between relative mortality with body mass index (BMI) may aid clinicians in making suitable clinical decisions. Our study evaluated the impact of BMI on mortality among cancer survivors.

Methods

We used data from the US National Health and Nutrition Examination Surveys (NHANES) spanning from 1999 to 2018. Relevant mortality data were retrieved up until December 31, 2019. Adjusted Cox models were employed to examine the association of BMI with the risks for total and cause-specific mortality.

Results

Among 4135 cancer survivors, 1486 (35.9%) were obese (21.0% class 1 obesity [BMI 30-< 35 kg/m²], 9.2% class 2 obesity [BMI 35 -< 40 kg/m²], 5.7% class 3 obesity [BMI ≥ 40 kg/m²]), 1475(35.7%) were overweight (BMI 25-< 30 kg/m²). During an average follow-up of 8.9 years (35895 person-years), a total of 1361 deaths were reported (cancer 392; 356 cardiovascular disease [CVD]; 613, non-cancer, non-CVD). In multivariable models, underweight participants (BMI < 18.5 kg/m²) were associated with significantly higher risks of cancer-specific (HR, 3.31; 95% CI, 1.37-8.03, P=0.01) and CVD cause (HR, 3.18; 95% CI, 1.44-7.02, P < 0.001) mortality compared to individuals with normal weight. Being overweight was associated with significantly lower risks of non-cancer, non-CVD cause mortality (HR, 0.66; 95% CI, 0.51-0.87, P < 0.001). Class 1 obesity was associated with significantly reduced risks of all-cause (HR, 0.78; 95% CI, 0.61-0.99, P = 0.04), and non-cancer, non-CVD cause (HR, 0.60; 95% CI, 0.42-0.86, P = 0.01) mortality. A higher risk of CVD-related mortality (HR, 2.35; 95% CI, 1.07-5.18, P = 0.03) was observed in class 3 obesity cases. Lower risks of all-cause mortality were detected in men (overweight, HR, 0.76; 95% CI, 0.59-0.99, P=0.04; class 1 obesity, HR, 0.69; 95% CI, 0.49-0.98, P = 0.04) but not in woman, in never-smokers (class 1 obesity, HR, 0.61; 95% CI, 0.41-0.90, P=0.01) and former smokers (overweight, HR, 0.77; 95% CI, 0.60-0.98, P=0.04) but not in current smokers; in obesity-related cancer (class 2 obesity, HR, 0.49; 95% CI, 0.27-0.89, P=0.01) but not in non-obesity-related cancers.

Conclusions

In the United States, cancer survivors with overweight or moderate obesity (class 1 or class 2 obesity) demonstrated a lower risk of all-cause and noncancer, non-CVD cause mortality.

Coronary circulatory function with increasing obesity: A complex U-turn

AIMS

The aim of this investigation was to explore and characterize alterations in coronary circulatory function in function of increasing body weight with medically controlled cardiovascular risk factors and, thus, "metabolically" unhealthy obesity.

MATERIALS AND METHODS

We prospectively enrolled 106 patients with suspected CAD but with normal stress-rest myocardial perfusion on 13 N-ammonia PET/CT and with medically controlled or no cardiovascular risk factors. 13 N-ammonia PET/CT concurrently determined myocardial blood flow (MBF) during pharmacologically induced hyperaemia and at rest. Based on body mass index (BMI), patients were grouped into normal weight (BMI: 20.0-24.9 kg/m2 , n = 22), overweight (BMI: 25.0-29.9 kg/m2 , n = 27), obese (BMI: 30.0-39.9 kg/m2 , n = 31), and morbidly obese (BMI ≥ 40kg/m2 , n = 26).

RESULTS

Resting MBF was comparable among groups (1.09 ± 0.18 vs. 1.00 ± 0.15 vs. 0.96 ± 0.18 vs.. 1.06 ± 0.31 ml/g/min; p = .279 by ANOVA). Compared to normal weight individuals, the hyperaemic MBF progressively decreased in in overweight and obese groups, respectively (2.54 ± 0.48 vs. 2.02 ± 0.27 and 1.75 ± 0.39 ml/g/min; p < .0001), while it increased again in the group of morbidly obese individuals comparable to normal weight (2.44 ± 0.41 vs. 2.54 ± 0.48 ml/g/min, p = .192). The BMI of the study population correlated with the hyperaemic MBF in a quadratic or U-turn fashion (r = .34, SEE = 0.46; p ≤ .002).

CONCLUSIONS

The U-turn of hyperaemic MBF from obesity to morbid obesity is likely to reflect contrasting effects of abdominal versus subcutaneous adipose tissue on coronary circulatory function indicative of two different disease entities, but needing further investigations.

[Value of three-dimensional speckle-tracking imaging in evaluating left ventricular systolic function and its correlation with peripheral arterial elasticity in children with simple obesity: a prospective study]

OBJECTIVES

To study the application of three-dimensional speckle-tracking imaging in evaluating left ventricular systolic function and its correlation with peripheral arterial elasticity in children with simple obesity.

METHODS

Random sampling combined with convenience sampling was used to obtain research samples, and then the samples were divided into an obesity group (23 cases), an overweight group (21 cases), and a normal group (24 cases). Three-dimensional speckle-tracking imaging was used to measure the global longitudinal strain (GLS), global radial strain (GRS), and global circumferential strain (GCS) of the left ventricle. An automatic arteriosclerosis tester was used to measure ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV). These parameters were compared among the three groups. The correlation of three-dimensional speckle-tracking parameters with ABI and baPWV was evaluated.

RESULTS

There were no significant differences in GLS, GRS, and GCS between the obesity and normal groups (P>0.05). The overweight group had a significantly higher GLS than the normal group [(-24±7) vs (-19±12), P<0.05]. The obesity and overweight groups had a significantly lower ABI than the normal group [(1.00±0.09)/(1.09±0.13) vs (2.25±0.13), P<0.05). The obesity group had a significantly higher baPWV than the normal group [(978±109) vs (905±22), P<0.05]. In the children with obesity, GLS was positively correlated with baPWV (r=0.516, P<0.05) , but not correlated with ABI (P>0.05), and GCS and GRS had no significant correlation with ABI or baPWV (P>0.05).

CONCLUSIONS

There are varying degrees of changes in left ventricular systolic function and peripheral arterial elasticity in children with simple obesity, and there is a certain correlation between them.

The Obesity Paradox in Spontaneous Intracerebral Hemorrhage: Results from a Retrospective Analysis of the Nationwide Inpatient Sample

BACKGROUND/OBJECTIVE

Mild obesity is associated with a survival benefit in cardiovascular and cerebrovascular disease. Only a few studies have analyzed the effect of obesity on outcomes after spontaneous intracerebral hemorrhage (ICH), and none have used a national US database. We sought to determine whether or not obesity was associated with outcomes and in-hospital complications following ICH.

METHODS

The Nationwide Inpatient Sample was used to identify patients with ICH in the USA who were discharged between 2002 and 2011. The presence of obesity (body mass index [BMI] 30-39.9) or morbid obesity (BMI ≥ 40) was noted. The primary outcome of interest was in-hospital mortality, and secondary outcomes included non-routine discharge disposition, tracheostomy or gastrostomy placement, length of stay (LOS), inflation-adjusted hospital charges, and in-hospital complications.

RESULTS

A total of 123,415 patients with ICH met the inclusion criteria, and the 10-year overall incidence of obesity was 4.5%. Between 2002 and 2011, the incidence of obesity increased from 1.9 to 4.4% and the incidence of morbid obesity increased from 0.7 to 3.2%. Both obese (OR 0.62, 95% CI 0.56-0.69) and morbidly obese (OR 0.76, 95% CI 0.66-0.88) patients had lower odds of inpatient mortality. Obese (OR 0.85, 95% CI 0.78-0.93) but not morbidly obese patients had lower odds of non-routine discharge. Morbidly obese patients were twice as likely to require a tracheostomy than non-obese patients (OR 2.07, 95% CI 1.62-2.66). Both obese and morbidly obese patients had higher total hospital charges and rates of pulmonary, renal, and venous thromboembolic complications. There was no difference in LOS according to body habitus.

CONCLUSIONS

In patients with spontaneous ICH, obesity is associated with decreased in-hospital mortality but higher rates of in-hospital complications and greater total hospital charges. Non-morbid obesity carries lower odds of non-routine hospital discharge.

Body composition and mortality in patients undergoing endovascular treatment for peripheral artery disease

An inverse correlation between body mass index and mortality in patients with peripheral artery disease (PAD) has been reported. However, little information is available regarding the impact of body composition on the clinical outcomes in patients with PAD. This study evaluated the relationships between the lean body mass index (LBMI), body fat % (BF%), and mortality and major amputation rate in patients with PAD. We evaluated 320 patients with PAD after endovascular treatment (EVT) enrolled from August 2015 to July 2016 and divided them into low and high LBMI and BF% groups based on their median values (17.47 kg/m² and 22.07%, respectively). We assessed 3-year mortality and major amputation for the following patient groups: Low LBMI/Low BF%, Low LBMI/High BF%, High LBMI/Low BF%, and High LBMI/High BF%. During the median 3.1-year follow-up period, 70 (21.9%) patients died and 9 (2.9%) patients experienced major amputation. The survival rate was lower in the Low LBMI than in the High LBMI group, and was not significantly different between the Low and High BF% groups. Survival rates were lowest in the Low LBMI/Low BF% group (57.5%) and highest in the High LBMI/High BF% group (94.4%). There were no significant differences in major amputation rate between the Low LBMI and High LBMI groups, and between the Low BF% and High BF% groups. The Low LBMI and Low BF% groups were associated with an increased risk of mortality after adjustment for age, sex, frailty and conventional risk factors [hazard ratio (HR): 4.02; 95% confidence interval (CI) 2.10–7.70; p < 0.001 and HR: 4.48; 95% CI 1.58–12.68, p = 0.005, respectively], for age, sex, hemodialysis, and prior cerebral cardiovascular disease (HR: 3.63; 95% CI 1.93–6.82; p < 0.001 and HR: 4.03; 95% CI 1.43–11.42, p = 0.009, respectively) and for age, sex, and laboratory date (HR: 3.97; 95% CI 1.88–8.37; p < 0.001 and HR: 3.31; 95% CI 1.15–9.53, p = 0.026, respectively). In conclusion, Low LBMI and Low BF% were associated with poor prognosis in patients undergoing EVT for PAD, and mortality was the lowest in the High LBMI/High BF% group compared with other body composition groups.

An unexpected paradox: wall shear stress in the aorta is less in patients with severe atherosclerosis regardless of obesity

BACKGROUND

Obesity is a widespread condition that is more prevalent in Western countries compared to others. Aortic atherosclerosis (AA) is a condition that frequently has been associated with obesity. An obesity paradox, where morbidly obese decedents had either no or minimal AA compared to nonobese decedents, recently has been described by some of us. The explanation for this almost counterintuitive paradox has yet to be determined, but a number of hypotheses were advanced, including hemodynamic factors producing aortic wall shear stress (WSS). The purpose of the present study was to determine if there was a relationship between AA and WSS, as determined by postmortem measurement of aortic wall diameters.

METHODS

Circumferences of the aorta at the levels of the ascending, thoracic and abdominal aorta were measured in 274 consecutive autopsies over 2-year period of time. AA was assessed using a previously described grading scale as either mild or severe. Circumferences were mathematically converted to diameters and WSS was calculated using the Hagen-Poiseuille formula. Two different methods to estimate cardiac output were used, both based on literature methods, one of which was body mass index (BMI) dependent, and the other BMI independent. Univariate and multivariable analyses of the relationship between WSS, age, BMI, gender, race and severity of AA were performed.

RESULTS

Of the 274 decedents, 140 had mild and 134 had moderate to severe AA. BMI <35 was associated with moderate to severe AA. WSS was inversely correlated with AA in all these segments of the aorta in each BMI subgroup with the exception of the ascending aorta for decedents with BMI ≤35 kg/m². Contrary to what we had hypothesized, WSS was not a determinant of the obesity paradox. However, among all the variables analyzed, a history of hypertension, diabetes mellitus and age were significant factors for developing AA (relative risk [RR] 0.35, P = .039; RR 1.51, P = .0006, RR 1.19, P = .0001, respectively).

CONCLUSIONS

Our data demonstrate that WSS was unexpectedly lower in decedents with moderate and severe AA as compared to those with mild AA. This observation, which requires further investigations, was seen in all BMI ranges and was confirmed by 2 methods to calculate WSS.

Impact of bariatric surgery on subclinical atherosclerosis in patients with morbid obesity

BACKGROUND

The main cause of death in obese individuals is cardiovascular disease precipitated by atherosclerosis. Endothelial dysfunction and inflammation are considered early events in the development of the disease.

OBJECTIVES

The aim of this study was to identify biomarkers of subclinical atherosclerosis in patients with morbid obesity by comparing clinical, vascular, and biochemical parameters indicative of endothelial dysfunction in patients with and without atheromatous plaque and monitoring changes after bariatric surgery.

SETTINGS

Multicenter collaboration between Biochemistry and Biomedicine Department in Barcelona University and University Hospital Arnau de Vilanova in Lleida.

METHODS

Plasma samples from 66 patients with morbid obesity were obtained before bariatric surgery and at 6 and 12 months after. Patients were divided into 2 groups based on the presence of atheromatous plaque. We used contrast-enhanced carotid ultrasound, enzyme-linked immunosorbent assay, Griess, and EndoPAT-2000 methods.

RESULTS

Patients with plaque showed the worst profile of cardiovascular risk factors. Carotid intima-media thickness and plasminogen activator inhibitor-1 were higher in plaque group (P < .0001). After bariatric surgery, vasa vasorum, oxidized low-density lipoprotein, and plasminogen activator inhibitor-1 decreased (P < .0001 in all cases).

CONCLUSIONS

Obesity promotes atherogenesis, leading to vascular endothelial damage. Bariatric surgery reduces cardiovascular risk and the prognosis is better for patients without plaque. The increase in plasminogen activator inhibitor-1, carotid intima-media thickness, and vasa vasorum proliferation might be the first alterations in the atheromatous process in obesity and could serve as good biomarkers of subclinical atherosclerosis.

APOE - a genetic marker of comorbidity in subjects with morbid obesity

Background

In population-based studies, the genetic variability of the APOE E alleles have been associated with health outcomes. Health problems are common in subjects with obesity. This study explored associations between the APOE E alleles and comorbidity in subjects with morbid obesity.

Methods

The study included consecutive subjects referred for evaluation of bariatric surgery with morbid obesity (defined as BMI > 40 or > 35 kg/m² with complications related to obesity). The subjects followed a conservative weight loss program for 6 months before surgery and had a follow-up visit 12 months after surgery. Demographic data and a set psychosomatic scores (musculoskeletal pain, WHO-5 Well-Being Index, Rosenberg Self-Esteem Scale, Hopkins Symptom Check-list 10; Epworth Sleepiness Scale, and Fatigue Severity Scale) were collected, and blood samples were analysed for haematological and biochemical parameters and APOE alleles.

Results

One hundred and forty subjects (men/women: 32 (23%)/108 (77%) with mean age 43.0 (SD 8.7) years and BMI 42.1 (SD 3.8) kg/m² were included. One hundred and eight and 92 subjects had data after conservative treatment and 12 months after surgery, respectively. The prevalence of the APOE alleles were: E2E2: 1 (0.7%), E2E3: 13 (9.3%), E2E4: 4 (2.9%), E3E3: 71 (50.7%), E3E4: 47 (33.6%), and E4E4: 4 (2.9%). The prevalence rates were as anticipated in a Norwegian population. The weight loss during conservative treatment and after bariatric surgery was independent of E allele variability. E2 was associated with a significant or clear trend toward improvement of all psychosomatic disorders. There was a significant fall in CRP during the two treatment periods with weight loss. E2 and E4 were significantly associated with high and low CRP, respectively, but no associations were seen between CRP and comorbidity.

Conclusions

The most marked finding was the association between E2 and improvement of all psychosomatic disorders. The positive and negative associations between CRP and E2 and E4, respectively, could indicate effects on inflammation and immunological reactions.

Using compartmental models to simulate directed acyclic graphs to explore competing causal mechanisms underlying epidemiological study data

Accurately estimating the effect of an exposure on an outcome requires understanding how variables relevant to a study question are causally related to each other. Directed acyclic graphs (DAGs) are used in epidemiology to understand causal processes and determine appropriate statistical approaches to obtain unbiased measures of effect. Compartmental models (CMs) are also used to represent different causal mechanisms, by depicting flows between disease states on the population level. In this paper, we extend a mapping between DAGs and CMs to show how DAG-derived CMs can be used to compare competing causal mechanisms by simulating epidemiological studies and conducting statistical analyses on the simulated data. Through this framework, we can evaluate how robust simulated epidemiological study results are to different biases in study design and underlying causal mechanisms. As a case study, we simulated a longitudinal cohort study to examine the obesity paradox: the apparent protective effect of obesity on mortality among diabetic ever-smokers, but not among diabetic never-smokers. Our simulations illustrate how study design bias (e.g. reverse causation), can lead to the obesity paradox. Ultimately, we show the utility of transforming DAGs into in silico laboratories within which researchers can systematically evaluate bias, and inform analyses and study design.

Association of obesity with arterial stiffness: The Multi-Ethnic Study of Atherosclerosis (MESA)

Arterial stiffness (AS) and obesity are recognized as important risk factors of cardiovascular disease (CVD). The purpose of this study was to investigate the relationship between AS and obesity. AS was defined as high augmentation index (AIx) and low elasticity (C1, large artery elasticity; C2, small artery elasticity) in participants enrolled in the Multi-Ethnic Study of Atherosclerosis at baseline. We compared AIx, C1, and C2 by body mass index (BMI) (< 25, 25-29.9, 30-39.9, ⩾ 40 kg/m²) and waist-hip ratio (WHR) (< 0.85, 0.85-0.99, ⩾ 1). The obesity-AS association was tested across 10-year age intervals. Among 6177 participants (62 ± 10 years old, 52% female), a significant inverse relationship was observed between obesity and AS. After adjustments for CVD risk factors, participants with a BMI > 40 kg/m² had 5.4% lower AIx (mean difference [Δ] = -0.82%; 95% CI: -1.10, -0.53), 15.4% higher C1 (Δ = 1.66 mL/mmHg ×10; 95% CI: 1.00, 2.33), and 40.2% higher C2 (Δ = 1.49 mL/mmHg ×100; 95% CI: 1.15, 1.83) compared to those with a BMI < 25 kg/m² (all p for trend < 0.001). Participants with a WHR ⩾ 1 had 5.6% higher C1 (∆ = 0.92 mL/mmHg ×10; 95% CI: 0.47, 1.37) compared to those with a WHR < 0.85. The WHR had a significant interaction with age on AIx and C2, but not with BMI; the inverse relationships of the WHR with AIx and C2 were observed only in participants < 55 years between the normal (WHR < 0.85) and the overweight (0.85 ⩽ WHR < 0.99) groups. Different associations of WHR and BMI with arterial stiffness among older adults should be further investigated.

[The «obesity paradox» and its degree of proof]

The article gives a critical assessment of the so-called obesity paradox. Methodological errors that occur in the organization of studies that studied the obesity paradox and the formation of comparison groups are highlighted. There are also examples of the disappearance of the obesity paradox when taking into account additional risk factors. The organization of prospective studies or more careful consideration of all currently known risk factors for cardiovascular diseases (CVD) will significantly improve the results of the study of the effect of overweight and obesity on mortality in patients with CVD. Thus, despite the biological possibility of the existence of a positive effect of adipose tissue in CVD, the presence of a large number of errors identified in the analysis of the work of researchers obesity paradox require to reconsider the existence of this phenomenon, it should be taken into account the possibility that the obesity paradox may be a consequence of improper design studies to investigate this phenomenon.

Obesity or BMI Paradox? Beneath the Tip of the Iceberg

The obesity paradox refers to extant evidence showing that obesity in older subjects or in patients with several chronic diseases may be protective and associated with decreased mortality. A number of mechanisms have been postulated to support the existence of obesity paradox; however, marked heterogeneity was found across studies and this has cast doubt on the actual presence of this phenomenon. The aim of the present narrative review is to summarize evidence underlying the concept of obesity paradox, focusing on limitations and bias related to this phenomenon, with emphasis on the use of body mass index (BMI). A major cause of the discrepancy between studies may be related to the use of BMI in the definition of obesity, that should consider, instead, excess body fat as the main characteristic of this disease and as the unique determinant of its complications. In addition, the adjustment for potential confounders (e.g., stage and grade of diseases, smoking habit, inability to capture the presence of signs of undernutrition in the normal-weight comparative group, consideration of body composition) may significantly scale down the protective role of obesity in terms of mortality. However, it is still necessary to acknowledge few biases (e.g., reverse causation, attrition bias, selection bias of healthy obese subjects or resilient survivors) that would still apply to obesity even when defined according with body composition. Further research should be prompted in order to promote correct phenotyping of patients in order to capture properly the trajectories of mortality in a number of diseases.

Body Mass Index and Major Adverse Cardiovascular Events: A Secondary Analysis Based on a Retrospective Cohort Study

Background

The association between body mass index (BMI) and major adverse cardiovascular events (MACE) has not been clarified and is controversial. Therefore, the purpose of present study is to explore the association between BMI and MACE.

Material/Methods

This was a secondary analysis of a retrospective cohort study in which 204 participants who were diagnosed with stable coronary artery disease (CAD) and received elective percutaneous coronary intervention (PCI) were recruited. According to the BMI, patients were divided into 3 categories – underweight (BMI <18.5 kg/m²), normal BMI (18.5 ≤BMI <25 kg/m²), and overweight (BMI ≥25 kg/m²)], and the patients were followed up. The primary endpoint was MACE.

Results

After a median follow-up of 783 days, MACE events had occurred in 18 participants. After controlling for potential confounding factors, no difference was observed in MACE between the underweight group and the normal BMI group (OR=1.73, 95% CI 0.42 to 7.17); but there were significantly fewer MACE in the overweight group than in the normal BMI group (OR=0.17; 95% CI: 0.03 to 0.84). Pearson correlation analysis showed that BMI was positively correlated with hemoglobin (r=0.2102) and albumin (r=0.2780), but negatively correlated with high-density lipoprotein cholesterol (r=−0.2052). The receiver operating characteristic curve (ROC) showed that the best threshold for BMI to predict MACE was 24.23, the area under the curve was 0.729, sensitivity was 0.893, and the specificity was 0.460.

Conclusions

Our study shows that overweight patient with stable CAD have lower risk of MACE after PCI, and the optimal threshold for predicting MACE is 24.23.

The continuums of impairment in vascular reactivity across the spectrum of cardiometabolic health: A systematic review and network meta-analysis

This study aimed to assess, for the first time, the change in vascular reactivity across the full spectrum of cardiometabolic health. Systematic searches were conducted in MEDLINE and EMBASE databases from their inception to March 13, 2017, including studies that assessed basal vascular reactivity in two or more of the following health groups (aged ≥18 years old): healthy, overweight, obesity, impaired glucose tolerance, metabolic syndrome, or type 2 diabetes with or without complications. Direct and indirect comparisons of vascular reactivity were combined using a network meta-analysis. Comparing data from 193 articles (7226 healthy subjects and 19344 patients), the network meta-analyses revealed a progressive impairment in vascular reactivity (flow-mediated dilation data) from the clinical onset of an overweight status (-0.41%, 95% CI, -0.98 to 0.15) through to the development of vascular complications in those with type 2 diabetes (-4.26%, 95% CI, -4.97 to -3.54). Meta-regressions revealed that for every 1 mmol/l increase in fasting blood glucose concentration, flow-mediated dilation decreased by 0.52%. Acknowledging that the time course of disease may vary between patients, this study demonstrates multiple continuums of vascular dysfunction where the severity of impairment in vascular reactivity progressively increases throughout the pathogenesis of obesity and/or insulin resistance, providing information that is important to enhancing the timing and effectiveness of strategies that aim to improve cardiovascular outcomes.

Unacylated Ghrelin Improves Vascular Dysfunction and Attenuates Atherosclerosis during High-Fat Diet Consumption in Rodents

Unacylated ghrelin (UnGhr) exerts several beneficial actions on vascular function. The aim of this study was to assess the effects of UnGhr on high-fat induced endothelial dysfunction and its underlying mechanisms. Thoracic aortas from transgenic mice, which were overexpressing UnGhr and being control fed either a standard control diet (CD) or a high-fat diet (HFD) for 16 weeks, were harvested and used for the assessment of vascular reactivity, endothelial nitric oxide synthase (eNOS) expression and activity, thiobarbituric acid reactive substances (TBARS) and glutathione levels, and aortic lipid accumulation by Oil Red O staining. Relaxations due to acetylcholine and to DEA-NONOate were reduced (p < 0.05) in the HFD control aortas compared to vessels from the CD animals. Overexpression of UnGhr prevented HFD-induced vascular dysfunction, while eNOS expression and activity were similar in all vessels. HFD-induced vascular oxidative stress was demonstrated by increased (p < 0.05) aortic TBARS and glutathione in wild type (Wt) mice; however, this was not seen in UnGhr mice. Moreover, increased (p < 0.05) HFD-induced lipid accumulation in vessels from Wt mice was prevented by UnGhr overexpression. In conclusion, chronic UnGhr overexpression results in improved vascular function and reduced plaque formation through decreased vascular oxidative stress, without affecting the eNOS pathway. This research may provide new insight into the mechanisms underlying the beneficial effects of UnGhr on the vascular dysfunction associated with obesity and the metabolic syndrome.

Leptin and the vasculature in young adults: The African-PREDICT study

BACKGROUND AND AIM

Information regarding the effect of leptin on the vasculature in young healthy adults at risk for cardiovascular disease development is limited. We therefore examined the associations between measures of subclinical atherosclerosis (carotid intima-media thickness, carotid cross-sectional wall area), large artery stiffness (pulse wave velocity) and a measure of endothelial dysfunction (von Willebrand factor [vWF]) with leptin in young healthy men and women.

METHODS

In a cross-sectional study in South Africa involving 820 normotensive individuals (337 men and 483 women) aged 20-30 years, we measured carotid intima-media thickness, carotid cross-sectional wall area, pulse wave velocity, vWF from citrated plasma and leptin from serum.

RESULTS

Despite sevenfold higher leptin in women than men (P < 0.001), only in young healthy men, we observed negative, independent associations between measures of carotid wall thickness (carotid intima-media thickness: R2  = 0.05; β = -0.20; P = 0.036; carotid cross-sectional wall area: R2  = 0.05; β = -0.20; P = 0.035) with leptin in multivariable-adjusted regression analyses. When reviewing these associations across body mass index categories, we found an association to be evident only in overweight men (carotid intima-media thickness: R2  = 0.15; β = -0.41; P = 0.007; carotid cross-sectional wall area: R2  = 0.21; β = -0.47; P = 0.002). No association was observed in the women or between pulse wave velocity and vWF with leptin.

CONCLUSION

In young healthy men, we found a beneficial inverse association between measures of carotid wall thickness and circulating leptin, thereby supporting a potential vascular protective role of leptin.

EFFECTS OF BODY WEIGHT REDUCTION ON ARTERIAL STIFFNESS AND ENDOTHELIAL FUNCTION AFTER BARIATRIC SURGERY IN MORBIDLY OBESE PATIENTS: A 4-YEAR CLINICAL STUDY

OBJECTIVE

To determine the long-term effect of weight loss on arterial stiffness, metabolic parameters in morbidly obese patients who underwent laparoscopic adjustable gastric banding (LAGB).

SUBJECTS

Forty-eight morbidly obese Caucasian subjects underwent LAGB from January 2009 to January 2010 and completed 4 years follow-up.

MEASUREMENTS

Patients were evaluated for body mass index (BMI), waist circumference, arterial blood pressure (BP), metabolic factors: leptin, adiponectin, glucose, glycated haemoglobin (HbA1c), insulin. Endothelial function - evaluated as reactive hyperemic index (RHI). Arterial stiffness - determined by cardio - ankle vascular index (CAVI).

RESULTS

Average BMI decreased from 46.48±7.06 kg/m2 to 39.78±7.36 kg/m2 (1year, p<0.001) and 37.29±7.49 kg/m2 (4years, p=0.012). The systolic BP and heart rate reduction were observed after the 4 years. Changes in cardiovascular parameters were accompanied by waist circumference reduction and improvement of glucose metabolism,reduction of insulin, HbA1c, leptin, C-reactive protein values. However, there were statistically significant increases in CAVI 6.58±1.77m/s vs. 7.03±2.00 m/s (p=0.014) at 1 year, but not significant 7.12±2.19 (p=0.153) after 4 years. Endothelial changes were observed only in diabetic patients one year after LAGB 2.18±0.57 vs. 1.86±0.34 (p=0.021) vs. 2.05±0.42 (p=0.086).

CONCLUSION

Weight reduction induced by LAGB was associated with changes in body weight and metabolic parameters, but it was no improvement on endothelial function and arterial stiffness.

Blood pressure predicts endothelial function and the effects of ethinyl estradiol exposure in young women

Hypertension, obesity, and endothelial function predict cardiovascular disease in women, and these factors are interrelated. We hypothesized that hypertension and obesity are associated with endothelial dysfunction in young women and that short-term ethinyl estradiol exposure mitigates this dysfunction. We examined flow-mediated dilation (FMD) responses before and during 7 days of oral ethinyl estradiol (30 µg/day) in 19 women (25 ± 5, 18-35 yr). We divided our sample into two groups based on two criteria: blood pressure and obesity. Women were divided into normal blood pressure (NBP; mean arterial pressure range: 78-91 mmHg, n = 7) and high blood pressure (HBP; mean arterial pressure range: 95-113 mmHg, n = 9) groups. We also stratified our subjects by body composition (lean: 18-31%, n = 8; obese: 38-59%, n = 9). We evaluated brachial FMD after two distinct shear stress stimuli: occlusion alone and occlusion with ischemic handgrip exercise. Obesity was unrelated to both FMD responses. Before ethinyl estradiol administration, the HBP group had blunted ischemic exercise responses relative to the NBP group (8.0 ± 3.5 vs. 12.3 ± 3.2%, respectively, P = 0.05). However, during ethinyl estradiol administration, ischemic exercise responses increased in the HBP group (12.8 ± 6.1%, P = 0.04) but decreased in the NBP group (5.6 ± 2.4%, P = 0.01). Standard FMD did not reveal differences between groups. In summary, 1) moderate HBP predicted endothelial impairment, 2) ethinyl estradiol administration had divergent effects on FMD in women with NBP versus HBP, and 3) enhanced FMD (ischemic handgrip exercise) revealed differences in endothelial function, whereas standard FMD (occlusion alone) did not. NEW & NOTEWORTHY We are the first to show that mild hypertension is a stronger predictor of endothelial dysfunction than obesity in healthy women without overt cardiovascular dysfunction. Importantly, the standard 5-min flow-mediated vasodilation stimulus did not detect endothelial dysfunction in our healthy population; only an enhanced ischemic handgrip exercise shear stress stimulus detected endothelial impairment. Estradiol administration increased flow-mediated dilation in women with high blood pressure, so it may be a therapeutic intervention to improve endothelial function.

Influence of obesity and metabolic syndrome on clinical outcomes of ST-segment elevation myocardial infarction in men undergoing primary percutaneous coronary intervention

BACKGROUND

The correlation between obesity and metabolic syndrome (MetS) and its impact on cardiovascular disease remains unclear. This study aims to investigate the impact of metabolic status and obesity on clinical outcomes of male patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

Data from the Korea Acute Myocardial Infarction Registry-National Institutes of Health registry were used to evaluate the impact of obesity and MetS on patients undergoing primary percutaneous coronary intervention (PPCI) from November 2005 to November 2015. Patients were grouped according to the presence or absence of obesity and MetS ('obese-/MetS-', 'obese-/MetS+', 'obese+/MetS-', or 'obese+/MetS+', respectively). All-cause death and major adverse cardiac events (MACE) were recorded during 12 months of follow-up.

RESULTS

A total of 14,357 patients were included. Multivariate analysis showed that the presence of MetS was an independent risk factor for all-cause death (HR 2.08, 95% CI 1.30-3.31, p=0.002) and cardiovascular death (HR 2.44, 95% CI 1.33-4.46, p=0.004) at 12 months among normal weight patients. The protective effect of obesity was observed, compared with the obese-/MetS+ group, in terms of all-cause death (HR 0.50, 95% CI 0.31-0.81, p=0.005) and cardiovascular death (HR 0.52, 95% CI 0.28-0.96, p=0.038; vs. total obese individuals), but it might have disappeared compared with the obese-/MetS- group. The rate of MACE did not differ significantly according to category by obesity and MetS.

CONCLUSIONS

The obesity paradox has not been observed between obese and normal weight patients without MetS. Risk stratification on the basis of the presence or absence of MetS is not a clinically useful indicator of outcome in obese male patients with STEMI after PPCI.

All-cause mortality among diabetic foot patients and related risk factors in Saudi Arabia

BACKGROUND

Although Diabetes mellitus is a major public health problem in the Middle East and North Africa (MENA) region with high rates of diabetic foot complications, there are only limited data concerning mortality among such a high risk group. Therefore, the main aim of the current study was to assess all-cause mortality and its related predictors among diabetic patients with and without diabetic foot complications.

METHODS

Using data from the Saudi National Diabetes Registry (SNDR), a total of 840 patients with type 1 or type 2 diabetes aged ≥25 years with current or past history of diabetic foot ulcer (DFU) or diabetes related lower extremity amputation (LEA) were recruited in 2007 from active patients' files and followed up to 2013. These patients were compared with an equal number of age and gender matched diabetic patients without foot complication recruited at the same period. All patients were subjected to living status verification at 31st December 2013.

RESULTS

The all-cause mortality rate among patients with DFU was 42.54 per 1000 person-years and among LEA patients was 86.80 per 1000 person-years among LEA patients for a total of 2280 and 1129 person-years of follow up respectively. The standardized mortality ratio (SMR) (95% CI) was 4.39 (3.55-5.23) and 7.21 (5.70-8.72) for cases with foot ulcer and LEA respectively. The percentage of deceased patients increased by almost twofold (18.5%) among patients with diabetic foot ulcer and more than threefold (32.2%) among patients with LEA compared with patients without diabetic foot complications (10.7%). The worst survival was among patients with LEA at 0.679 and the presence of diabetic nephropathy was the only significant independent risk factor for all-cause mortality among patients with diabetic foot complications. On the other hand, obese patients have demonstrated significantly reduced all-cause mortality rate.

CONCLUSIONS

Diabetic patients with diabetic foot complications have an excess mortality rate when compared with diabetic counterparts without foot complications and the general population. Early interventions to prevent foot ulceration and consequent LEA as well as all the measurements for reducing the prevalence of microvascular and macrovascular complications should be considered.

Evaluation of the impact of statin therapy on the obesity paradox in patients with acute myocardial infarction: A propensity score matching analysis from the Korea Acute Myocardial Infarction Registry

The phenomenon of obesity paradox after acute myocardial infarction (AMI) has been reported under strong recommendation of statin therapy. However, the impact of statin therapy on this paradox has not been investigated. This study investigated the impact of statin therapy on 1-year mortality according to obesity after AMI. A total of 2745 AMI patients were included from the Korea Acute Myocardial Infarction Registry after 1:4 propensity score matching analysis (n = 549 for nonstatin group and n = 2196 for statin group). Primary and secondary outcomes were all-cause and cardiac death, respectively. During 1-year follow-up, the incidence of all-cause (8.4% vs 3.7%) and cardiac (6.2% vs 2.3%) death was higher in nonstatin group than in statin (P < .001, respectively). In nonstatin group, the incidence of all-cause (7.2% vs 9.0%) and cardiac (5.5% vs 6.5%) death did not differ significantly between obese and nonobese patients. However, in statin group, obese patients had lower 1-year rate of all-cause (1.7% vs 4.8%) and cardiac (1.2% vs 2.9%) death (P < .05, respectively), and lower cumulative rates by Kaplan-Meier analysis of all-cause and cardiac death compared with nonobese patients (log-rank P < .05, respectively). The overall risk of all-cause death was significantly lower in obese than in nonobese patients only in statin group (hazard ratio: 0.35; P = .001). After adjusting for confounding factors, obesity was independently associated with decreased risk of all-cause death in statin group. In conclusion, the greater benefit of statin therapy for survival in obese patients is further confirmation of the obesity paradox after AMI.

Anti-obesity and anti-diabetic effects of nitrate and nitrite

Prevalence of obesity is increasing worldwide and type 2 diabetes to date is the most devastating complication of obesity. Decreased nitric oxide bioavailability is a feature of obesity and diabetes that links these two pathologies. Nitric oxide is synthesized both by nitric oxide synthase enzymes from l-arginine and nitric oxide synthase-independent from nitrate/nitrite. Nitric oxide production from nitrate/nitrite could potentially be used for nutrition-based therapy in obesity and diabetes. Nitric oxide deficiency also contributes to pathogeneses of cardiovascular disease and hypertension, which are associated with obesity and diabetes. This review summarizes pathways for nitric oxide production and focuses on the anti-diabetic and anti-obesity effects of the nitrate-nitrite-nitric oxide pathway. In addition to increasing nitric oxide production, nitrate and nitrite reduce oxidative stress, increase adipose tissue browning, have favorable effects on nitric oxide synthase expression, and increase insulin secretion, all effects that are potentially promising for management of obesity and diabetes. Based on current data, it could be suggested that amplifying the nitrate-nitrite-nitric oxide pathway is a diet-based strategy for increasing nitric oxide bioavailability and the management of these two interlinked conditions. Adding nitrate/nitrite to drugs that are currently used for managing diabetes (e.g. metformin) and possibly anti-obesity drugs may also enhance their efficacy.

Obesity, arterial function and arterial structure - a systematic review and meta-analysis

OBJECTIVE

Obesity is an established risk factor for cardiovascular disease. The mechanisms by which obesity affects cardiovascular risk have not been fully elucidated. This paper reports a comprehensive systematic review and meta-analysis on obesity and two key aspects of vascular health using gold-standard non-invasive measures - arterial endothelial function (brachial flow-mediated dilatation) and subclinical atherosclerosis (carotid intima-media thickness).

METHODS

Electronic searches for 'Obesity and flow-mediated dilatation' and 'Obesity and intima-media thickness' were performed using Ovid Medline and Embase databases. A meta-analysis was undertaken for brachial flow-mediated dilatation and carotid intima-media thickness to obtain pooled estimates for adults with obesity and those with healthy weight.

RESULTS

Of the 5,810 articles retrieved, 19 studies on flow-mediated dilatation and 19 studies on intima-media thickness were included. Meta-analysis demonstrated that obesity was associated with lower flow-mediated dilatation (-1.92 % [95% CI -2.92, -0.92], P = 0.0002) and greater carotid intima-media thickness (0.07 mm [95% CI 0.05, 0.08], P < 0.0001).

CONCLUSIONS

Obesity is associated with poorer arterial endothelial function and increased subclinical atherosclerosis, consistent with these aspects of vascular health at least partially contributing to the increased risk of cardiovascular events in adults with obesity. These estimated effect sizes will enable vascular health benefits in response to weight loss treatment to be put in greater perspective, both in the research setting and potentially also clinical practice.

Analysis of Body Mass Index and Mortality in Patients With Colorectal Cancer Using Causal Diagrams

IMPORTANCE

Physicians and investigators have sought to determine the relationship between body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) and colorectal cancer (CRC) outcomes, but methodologic limitations including sampling selection bias, reverse causality, and collider bias have prevented the ability to draw definitive conclusions.

OBJECTIVE

To evaluate the association of BMI at the time of, and following, colorectal cancer (CRC) diagnosis with mortality in a complete population using causal diagrams.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective observational study with prospectively collected data included a cohort of 3408 men and women, ages 18 to 80 years, from the Kaiser Permanente Northern California population, who were diagnosed with stage I to III CRC between 2006 and 2011 and who also had surgery.

EXPOSURES

Body mass index at diagnosis and 15 months following diagnosis.

MAIN OUTCOMES AND MEASURES

Hazard ratios (HRs) for all-cause mortality and CRC-specific mortality compared with normal-weight patients, adjusted for sociodemographics, disease severity, treatment, and prediagnosis BMI.

RESULTS

This study investigated a cohort of 3408 men and women ages 18 to 80 years diagnosed with stage I to III CRC between 2006 and 2011 who also had surgery. At-diagnosis BMI was associated with all-cause mortality in a nonlinear fashion, with patients who were underweight (BMI <18.5; HR, 2.65; 95% CI, 1.63-4.31) and patients who were class II or III obese (BMI ≥35; HR, 1.33; 95% CI, 0.89-1.98) exhibiting elevated mortality risks, compared with patients who were low-normal weight (BMI 18.5 to <23). In contrast, patients who were high-normal weight (BMI 23 to <25; HR, 0.77; 95% CI, 0.56-1.06), low-overweight (BMI 25 to <28; HR, 0.75; 95% CI, 0.55-1.04), and high-overweight (BMI 28 to <30; HR, 0.52; 95% CI, 0.35-0.77) had lower mortality risks, and patients who were class I obese (BMI 30 to <35) showed no difference in risk. Spline analysis confirmed a U-shaped relationship in participants with lowest mortality at a BMI of 28. Associations with CRC-specific mortality were similar. Associations of postdiagnosis BMI and mortality were also similar, but patients who were class I obese had significantly lower all-cause and cancer-specific mortality risks.

CONCLUSIONS AND RELEVANCE

In this study, body mass index at the time of diagnosis and following diagnosis of CRC was associated with mortality risk. Though evidence shows that exercise in patients with cancer should be encouraged, findings suggest that recommendations for weight loss in the immediate postdiagnosis period among patients with CRC who are overweight may be unwarranted.

Overweight status is associated with extensive signs of microvascular dysfunction and cardiovascular risk

The aim of this present study was to investigate if overweight individuals exhibit signs of vascular dysfunction associated with a high risk for cardiovascular disease (CVD). One hundred lean and 100 overweight participants were recruited for the present study. Retinal microvascular function was assessed using the Dynamic Retinal Vessel Analyser (DVA), and systemic macrovascular function by means of flow-mediated dilation (FMD). Investigations also included body composition, carotid intimal-media thickness (c-IMT), ambulatory blood pressure monitoring (BP), fasting plasma glucose, triglycerides (TG), cholesterol levels (HDL-C and LDL-C), and plasma von Willebrand factor (vWF). Overweight individuals presented with higher right and left c-IMT (p = 0.005 and p = 0.002, respectively), average 24-h BP values (all p < 0.001), plasma glucose (p = 0.008), TG (p = 0.003), TG: HDL-C ratio (p = 0.010), and vWF levels (p = 0.004). Moreover, overweight individuals showed lower retinal arterial microvascular dilation (p = 0.039) and baseline-corrected flicker (bFR) responses (p = 0.022), as well as, prolonged dilation reaction time (RT, p = 0.047). These observations emphasise the importance of vascular screening and consideration of preventive interventions to decrease vascular risk in all individuals with adiposity above normal range.

Excess weight and life expectancy after acute myocardial infarction: The obesity paradox reexamined

BACKGROUND

An "obesity paradox" has been described in patients with acute myocardial infarction (AMI), whereby obese and overweight patients have a lower risk of short-term mortality after AMI than normal-weight patients. However, the long-term association of obesity with mortality after AMI remains unknown.

METHODS

We used data from the Cooperative Cardiovascular Project, a prospective medical record study of Medicare beneficiaries hospitalized with AMI with 17 years of follow-up (N = 124,981), to evaluate the association of higher body mass index (BMI) with short- and long-term survival after AMI. Cox proportional hazards models were used to estimate life expectancy after AMI and the years of potential life lost or gained attributable to excess weight.

RESULTS

Approximately 41.5% of patients were classified as normal weight; 38.7%, as overweight; 14.3%, as obese; and 5.5%, as morbidly obese. Normal-weight patients had the highest crude mortality at all follow-up time points, whereas obese patients had the lowest. Adjustment for patient and treatment characteristics reduced this difference, but the survival benefit persisted in overweight and obese patients at all time points. Morbidly obese and normal-weight patients had a comparable risk of death at 17 years. Life expectancy estimates were generally lowest for morbidly obese patients and highest for overweight patients. Differences in life expectancy between BMI groups were most pronounced in younger patients. After adjustment, overweight and obesity were associated with greater life years at all ages; however, morbid obesity was only associated with better survival in patients ≥75 years of age at the time of AMI.

CONCLUSIONS

Overweight and obesity are associated with improved short- and long-term survival after AMI, which results in moderate gains in life expectancy relative to normal-weight patients. These findings suggest that higher BMI confers a protective advantage over the entire remaining lifespan in older patients with AMI.

Impaired handgrip exercise-induced brachial artery flow-mediated dilation in young obese males

Flow mediated dilation (FMD) stimulated by different shear stress stimulus profiles may recruit distinct transduction mechanisms, and provide distinct information regarding endothelial function. The purpose of this study was to determine whether obesity influences brachial artery FMD differently depending on the shear stress profile used for FMD assessment. The FMD response to a brief, intermediate, and sustained shear stress profile was assessed in obese (n = 9) and lean (n = 19) young men as follows: brief stimulus, standard reactive hyperemia (RH) following a 5 min forearm occlusion (5 min RH); intermediate stimulus, RH following a 15 min forearm occlusion (15 min RH); sustained stimulus, 10 min of handgrip exercise (HGEX). Brachial artery diameter and mean shear stress were assessed using echo and Doppler ultrasound, respectively, during each FMD test. There was no group difference in HGEX shear stress (p = 0.390); however, the obese group had a lower HGEX-FMD (5.2 ± 3.0% versus 11.5 ± 4.4%, p < 0.001). There was no group difference in 5 min RH-FMD (p = 0.466) or 15 min RH-FMD (p = 0.181); however, the shear stress stimulus was larger in the obese group. After normalization to the stimulus the 15 min RH-FMD (p = 0.002), but not the 5 min RH-FMD (p = 0.118) was lower in the obese group. These data suggest that obesity may have a more pronounced impact on the endothelium's ability to respond to prolonged increases in shear stress.

Insights into the molecular mechanisms of diabetes-induced endothelial dysfunction: focus on oxidative stress and endothelial progenitor cells

Diabetes mellitus is a heterogeneous, multifactorial, chronic disease characterized by hyperglycemia owing to insulin insufficiency and insulin resistance (IR). Recent epidemiological studies showed that the diabetes epidemic affects 382 million people worldwide in 2013, and this figure is expected to be 600 million people by 2035. Diabetes is associated with microvascular and macrovascular complications resulting in accelerated endothelial dysfunction (ED), atherosclerosis, and cardiovascular disease (CVD). Unfortunately, the complex pathophysiology of diabetic cardiovascular damage is not fully understood. Therefore, there is a clear need to better understand the molecular pathophysiology of ED in diabetes, and consequently, better treatment options and novel efficacious therapies could be identified. In the light of recent extensive research, we re-investigate the association between diabetes-associated metabolic disturbances (IR, subclinical inflammation, dyslipidemia, hyperglycemia, dysregulated production of adipokines, defective incretin and gut hormones production/action, and oxidative stress) and ED, focusing on oxidative stress and endothelial progenitor cells (EPCs). In addition, we re-emphasize that oxidative stress is the final common pathway that transduces signals from other conditions-either directly or indirectly-leading to ED and CVD.

NO-Rich Diet for Lifestyle-Related Diseases

Decreased nitric oxide (NO) availability due to obesity and endothelial dysfunction might be causally related to the development of lifestyle-related diseases such as insulin resistance, ischemic heart disease, and hypertension. In such situations, instead of impaired NO synthase (NOS)-dependent NO generation, the entero-salivary nitrate-nitrite-NO pathway might serve as a backup system for NO generation by transmitting NO activities in the various molecular forms including NO and protein S-nitrosothiols. Recently accumulated evidence has demonstrated that dietary intake of fruits and vegetables rich in nitrate/nitrite is an inexpensive and easily-practicable way to prevent insulin resistance and vascular endothelial dysfunction by increasing the NO availability; a NO-rich diet may also prevent other lifestyle-related diseases, including osteoporosis, chronic obstructive pulmonary disease (COPD), and cancer. This review provides an overview of our current knowledge of NO generation through the entero-salivary pathway and discusses its safety and preventive effects on lifestyle-related diseases.

Diabetic foot complications and their risk factors from a large retrospective cohort study

BACKGROUND

Foot complications are considered to be a serious consequence of diabetes mellitus, posing a major medical and economical threat. Identifying the extent of this problem and its risk factors will enable health providers to set up better prevention programs. Saudi National Diabetes Registry (SNDR), being a large database source, would be the best tool to evaluate this problem.

METHODS

This is a cross-sectional study of a cohort of 62,681 patients aged ≥ 25 years from SNDR database, selected for studying foot complications associated with diabetes and related risk factors.

RESULTS

The overall prevalence of diabetic foot complications was 3.3% with 95% confidence interval (95% CI) of (3.16%-3.44%), whilst the prevalences of foot ulcer, gangrene, and amputations were 2.05% (1.94%-2.16%), 0.19% (0.16%-0.22%), and 1.06% (0.98%-1.14%), respectively. The prevalence of foot complications increased with age and diabetes duration predominantly amongst the male patients. Diabetic foot is more commonly seen among type 2 patients, although it is more prevalent among type 1 diabetic patients. The Univariate analysis showed Charcot joints, peripheral vascular disease (PVD), neuropathy, diabetes duration ≥ 10 years, insulin use, retinopathy, nephropathy, age ≥ 45 years, cerebral vascular disease (CVD), poor glycemic control, coronary artery disease (CAD), male gender, smoking, and hypertension to be significant risk factors with odds ratio and 95% CI at 42.53 (18.16-99.62), 14.47 (8.99-23.31), 12.06 (10.54-13.80), 7.22 (6.10-8.55), 4.69 (4.28-5.14), 4.45 (4.05-4.89), 2.88 (2.43-3.40), 2.81 (2.31-3.43), 2.24 (1.98-2.45), 2.02 (1.84-2.22), 1.54 (1.29-1.83), and 1.51 (1.38-1.65), respectively.

CONCLUSIONS

Risk factors for diabetic foot complications are highly prevalent; they have put these complications at a higher rate and warrant primary and secondary prevention programs to minimize morbidity and mortality in addition to economic impact of the complications. Other measurements, such as decompression of lower extremity nerves, should be considered among diabetic patients.

The short-term effect of bariatric surgery on non-invasive markers of artery function in patients with metabolic syndrome

BACKGROUND

An improved understanding of the vascular function, measured in non-invasive way, in constantly growing group of patients at increased risk of cardiovascular events is necessary. To evaluate the effects of metabolic syndrome in morbidly obese patients and body mass reduction secondary to gastric bypass surgery on convenient and new non-invasive markers of artery function: pulse wave velocity (PWV), flow- and nitroglycerin-mediated dilatation (FMD, NTG).

METHODS

There were 40 patients included into prospective study, who were qualified for bariatric surgery (OB1) and evaluated again 6 m after surgery (OB2). A control group (CG) consisted of 15 healthy women. A second control group (CG2) consisted of 15 women with grade 1 obesity. PWV, FMD, NTG were assessed.

RESULTS

The reduction of BMI (kg/m(2)) from 47.73 ± 6.18 (OB1) to 35.22 ± 5.20 (OB2) was observed. The PWV turned out to be higher before bariatric surgery (OB1 vs. OB2 8.53 ± 1.76 vs. 7.82 ± 1.49 m/s; p < 0.001), however it was no different than PWV in CG. In OB1 group PWV showed correlation with age (r = 0.492, p = 0.001), HR (r = 0.324, p = 0.04), %FM (r = 0.328; p = 0.039), NTG% (r = -0.332, p = 0.036) as well as hsCRP (r = 0.394, p = 0.014). A multivariate analysis showed that the most significant factors influencing PWV were age (p = 0.0005) and hsCRP (p = 0.0014), pseudo R(2) index 0.44365. The values of FMD differed between OB1 and OB2 groups (12.83 ± 5.15 vs. 17.52 ± 5.50 %; p < 0.0001), however, they were similar to results obtained in CG (14.45 ± 6.14 %; NS). The values of nitroglycerin-mediated dilatation differed between OB1 and OB2 groups (21.47 ± 8.31 vs. 28.54 ± 8.16 %; p < 0.0001) and were lower as compared with CG (31.42 ± 5.95 %; p = 0.0005).

CONCLUSION

Body mass reduction secondary to bariatric surgery in patients with severe obesity and metabolic syndrome results in improvement of functional markers of artery function and advantageous metabolic changes. The improvement in functional markers of artery function (NTG%) was correlated with change in triglyceride blood concentration.

Subclinical atherosclerosis determinants in morbid obesity

BACKGROUND AND AIMS

Obesity is associated with increased cardiovascular risk. However, the impact of morbid obesity on vascular structure and function is not well understood. This study was designed to appraise subclinical atherosclerosis markers, including carotid intima media thickness (cIMT), endothelial function, and arterial wall stiffness, and their determinants, in morbidly obese patients.

METHODS AND RESULTS

In this cross-sectional study 194 overweight and obese patients were distributed in morbid-obese patients (MOP, n = 110), obese (OP, n = 84) and overweight patients (OwP, n = 33) groups. Demography, anthropometry, clinical and standard biochemical data were recorded. cIMT, endothelial function, defined as the small artery reactivity index (saRHI), and artery wall rigidity, studied by the augmentation index, were determined. More than 50% of the MOP, OP and OwP had a cIMT above the 75th percentile per age and gender. No differences in cIMT or saRHI were observed, although overweight and obese patients (OOP) had higher arterial rigidity compared with the morbid-obese patients. In a multivariate regression test, while cholesterol was the main determinant of cIMT in overweight and obese patients, glucose metabolism was the determinant in MOP.

CONCLUSION

More than half of the population have a cIMT above general population ranges. OwP, OP and MOP have similar cIMT and saRHI. However, OOP have greater arterial wall rigidity. Dysglycemia is the main factor associated with subclinical atherosclerosis in MOP.

Regulation of obesity and insulin resistance by nitric oxide

Obesity is a risk factor for developing type 2 diabetes and cardiovascular disease and has quickly become a worldwide pandemic with few tangible and safe treatment options. Although it is generally accepted that the primary cause of obesity is energy imbalance, i.e., the calories consumed are greater than are utilized, understanding how caloric balance is regulated has proven a challenge. Many "distal" causes of obesity, such as the structural environment, occupation, and social influences, are exceedingly difficult to change or manipulate. Hence, molecular processes and pathways more proximal to the origins of obesity-those that directly regulate energy metabolism or caloric intake-seem to be more feasible targets for therapy. In particular, nitric oxide (NO) is emerging as a central regulator of energy metabolism and body composition. NO bioavailability is decreased in animal models of diet-induced obesity and in obese and insulin-resistant patients, and increasing NO output has remarkable effects on obesity and insulin resistance. This review discusses the role of NO in regulating adiposity and insulin sensitivity and places its modes of action into context with the known causes and consequences of metabolic disease.

Obesity and overweight associated with increased carotid diameter and decreased arterial function in young otherwise healthy men

BACKGROUND

Obesity is linked to cardiovascular disease, stroke, increased mortality and vascular remodeling. Although increased arterial diameter is associated with multiple cardiovascular risk factors and obesity, it is unknown whether lumen enlargement is accompanied by unfavorable vascular changes in young and otherwise healthy obese individuals. The purpose of this study was to compare carotid and brachial artery diameter, blood pressure, arterial stiffness, and endothelial function in young, apparently healthy, normal-weight, overweight, and obese male subjects.

METHODS

One hundred sixty-five male subjects (27.39±0.59 years) were divided into 3 groups (normal weight, overweight, and obese) according to body mass index. Subjects underwent cardiovascular measurements to determine arterial diameter, function, and stiffness.

RESULTS

After adjusting for age, the obese group had significantly greater brachial, carotid, and aortic pressures, brachial pulse wave velocity, carotid intima media thickness, and carotid arterial diameter compared with both the overweight and normal-weight groups.

CONCLUSIONS

Obesity is associated with a much worse arterial profile, as an increased carotid lumen size was accompanied by higher blood pressure, greater arterial stiffness, and greater carotid intima media thickness in obese compared with overweight or normal-weight individuals. These data suggest that although obesity may be a factor in arterial remodeling, such remodeling is also accompanied by other hemodynamic and arterial changes consistent with reduced arterial function and increased cardiovascular risk.

Endothelial progenitor cells as a cardiometabolic risk factor marker in prediabetes

OBJECTIVE

Endothelial progenitor cells (EPCs) have recently been considered as a potential novel marker of vascular integrity, atherosclerosis and cardiovascular risk. This study was performed to investigate the main determinants of EPC levels in individuals with prediabetes.

DESIGN

Thirty-nine participants with newly diagnosed prediabetes were enrolled. Flow cytometric analysis was used to quantify EPCs (CD34+CD133+VEGFR-2+). Traditional risk factors, high-sensitivity C-reactive protein (hs-CRP), homeostasis model assessment of insulin resistance (HOMA-IR) and anthropometric parameters, including ultrasonographic-determined visceral and subcutaneous fat, were recorded.

RESULTS

In univariate analysis, EPC levels significantly correlated with waist circumference (p=0.017), mean arterial pressure (p=0.009), total cholesterol (p=0.003), hs-CRP (p=0.006), HOMA-IR (p=0.031) and visceral fat (p=0.040). However, in stepwise multivariate ordinal logistic regression analysis, only visceral fat retained its statistical significance (OR=0.79, 95%Cl:0.64-0.98, p=0.032).

CONCLUSIONS

Visceral fat seems to be the main determinant of EPC levels in individuals with prediabetes and to form a plausible link between mild metabolic abnormalities, cardiovascular risk and vascular homeostasis process.

Obesity and cardiovascular outcomes: a review

The prevalence of obesity is increasing at an epidemic rate globally with more than 1 billion adults overweight and at least 300 million of them clinically obese. This is expected to rise further in the next 20 to 30 years. Obesity is known to be an independent risk factor for serious health conditions, including hypertension, type 2 diabetes, and cardiovascular diseases. Given the association of obesity with cardiovascular disease, it could be speculated that obese individuals would have adverse outcomes after a cardiovascular event compared to those with normal body mass index (BMI). However, various studies have reported a paradoxical U-shaped relationship between obesity and mortality from various diseases, including myocardial infarction and heart failure, suggesting that patients with higher BMI have similar or lower short- and long-term mortality rates. This phenomenon has been termed the 'obesity paradox' or 'reverse epidemiology'. The goal of this review is to evaluate the potential mechanisms behind the obesity paradox and its implications.

Antiobesogenic role of endothelial nitric oxide synthase

The prevalence of obesity has increased remarkably in the past four decades. Because obesity can promote the development of type 2 diabetes and cardiovascular disease, understanding the mechanisms that engender weight gain and discovering safe antiobesity therapies are of critical importance. In particular, the gaseous signaling molecule, nitric oxide (NO), appears to be a central factor regulating adiposity and systemic metabolism. Obese and diabetic states are characterized by a deficit in bioavailable NO, with such decreases commonly attributed to downregulation of endothelial NO synthase (eNOS), loss of eNOS activity, or quenching of NO by its reaction with oxygen radicals. Gain-of-function studies, in which vascular-derived NO has been increased pharmacologically or genetically, reveal remarkable actions of NO on body composition and systemic metabolism. This review addresses the metabolic actions of eNOS and the potential therapeutic utility of harnessing its antiobesogenic effects.

High-density lipoprotein cholesterol affects early endothelial progenitor cell number and endothelial function in obese women

OBJECTIVE

In order to improve our understanding of high-density lipoprotein cholesterol (HDL-C) cardiovascular (CV) impact in obesity, the association of HDL-C plasma level with circulating early endothelial progenitor cell (early-EPC) number and endothelium-dependent vasodilatation (EDV) in obese women with normal or high low-density lipoprotein cholesterol (LDL-C) plasma levels was evaluated.

DESIGN AND METHODS

One hundred thirteen obese female subjects and a control group of 78 healthy female subjects were recruited. Circulating early-EPC were assessed by single- and two-color flow cytometric analyses with a fluorescence activated cell sorting (FACScan) flow cytometer. EDV was evaluated as response to ischemia by strain gauge plethysmography.

RESULTS

Both early-EPC number and EDV were significantly decreased in obese women compared with the control group. Obese women with low HDL-C showed a further decrease of early-EPC and EDV in the presence of both high or normal LDL-C plasmatic levels. In the normal HDL-C level subgroup, hypercholesterolemic and nonhypercholesterolemic subjects showed no difference in early-EPC number, whereas slight EDV impairment was present in hypercholesterolemic subjects.

CONCLUSION

In obese women, low HDL-C is associated to decreased early-EPC number and impaired EDV, suggesting the need to assess whether evaluation of early-EPC and EDV may increase HDL-C prognostic value in the stratification of CV risk.

Obesity impairs vasodilatation and blood flow increase mediated by endothelial nitric oxide: an overview

Obesity dramatically increases the risk of development of cardiovascular and metabolic diseases. Endothelial dysfunction induced by obesity is an important risk factor that impairs blood flow controls in various organs. Impaired endothelial function occurs early in life in obese children. Obesity-induced endothelial dysfunction is associated with decreased nitric oxide (NO) production due to impaired endothelial NO synthase activity and expression and increased production of superoxide anion and the endogenous NOS inhibitor ADMA, together with increased vasoconstrictor factors, such as endothelin-1 and sympathetic nerve activation. Decreased endothelial progenitor cells are also involved in endothelial cell senescence in obese individuals. Insulin resistance and diabetes mellitus augment obesity-induced endothelial dysfunction. Adipokines liberated from adipose tissues play roles in modulating endothelial function; adiponectin and ghrelin have beneficial effects on endothelial cells. Effects of leptin on endothelial function are controversial. Decreased body weight by physical exercise, dietary interventions, and bariatric surgery are effective measures that reverse endothelial dysfunction; however, the weight control is not only the reason for improving of endothelia function. Pharmacological therapies with β-adrenoceptor antagonists, resveratolol, anti-obesity agents, nifedipine, and NADPH oxidase inhibitors may also be effective; however, these treatments have to be utilized under the basis of exercise and dietary controls.