Measurement of abdominal fat by CT compared to waist circumference and BMI in explaining the presence of coronary calcium

Deep Learning-based Quantification of Abdominal Subcutaneous and Visceral Fat Volume on CT Images

RATIONALE AND OBJECTIVES

Develop a deep learning-based algorithm using the U-Net architecture to measure abdominal fat on computed tomography (CT) images.

MATERIALS AND METHODS

Sequential CT images spanning the abdominal region of seven subjects were manually segmented to calculate subcutaneous fat (SAT) and visceral fat (VAT). The resulting segmentation maps of SAT and VAT were augmented using a template-based data augmentation approach to create a large dataset for neural network training. Neural network performance was evaluated on both sequential CT slices from three subjects and randomly selected CT images from the upper, central, and lower abdominal regions of 100 subjects.

RESULTS

Both subcutaneous and abdominal cavity segmentation images created by the two methods were highly comparable with an overall Dice similarity coefficient of 0.94. Pearson's correlation coefficients between the subcutaneous and visceral fat volumes quantified using the two methods were 0.99 and 0.99 and the overall percent residual squared error were 5.5% and 8.5%. Manual segmentation of SAT and VAT on the 555 CT slices used for testing took approximately 46 hours while automated segmentation took approximately 1 minute.

CONCLUSION

Our data demonstrates that deep learning methods utilizing a template-based data augmentation strategy can be employed to accurately and rapidly quantify total abdominal SAT and VAT with a small number of training images.

Influence of Waist-to-Hip Ratio on the Prognosis of Heart Failure Patients With Revascularized Coronary Heart Disease

Background: Heart failure (HF) is considered one of the most common complications of coronary heart disease (CHD), with a higher incidence of readmission and mortality. Thus, exploring the risk factors related to the prognosis is necessary. Moreover, the effect of the waist-to-hip ratio (WHR) on HF patients with revascularized CHD is still unclear. Thus, we aimed to assess the influence of WHR on the prognosis of HF patients with revascularized CHD. Methods: We collected data of HF patients with revascularized CHD who were referred to the Cardiac Rehabilitation Clinic of PLA Hospital from June 30, 2015, to June 30, 2019. Cox proportional hazard regression analysis was used to determine the relationship between WHR and prognosis of HF patients with revascularized CHD. Patients were divided into higher and lower WHR groups based on the cutoff WHR value calculated by the X-tile software. Cox regression analysis was used to analysis the two groups. We drew the receiver operating characteristic curve (ROC) of WHR and analyzed the differences between the two groups. Endpoints were defined as major adverse cardiac events (MACE) (including all-cause mortality, non-fatal myocardial infarction, unscheduled revascularization, and stroke). Results: During the median follow-up of 39 months and maximum follow-up of 54 months, 109 patients were enrolled, of which 91.7% were males, and the mean age was 56.0 ± 10.4 years. WHR was associated with the incidence of MACE in the Cox regression analysis (p = 0.001); an increase in WHR of 0.01 unit had a hazard ratio (HR) of 1.134 (95%CI: 1.057-1.216). The WHR cutoff value was 0.93. Patients in the higher WHR group had a significantly higher risk of MACE than those in the lower WHR group (HR = 7.037, 95%CI: 1.758-28.168). The ROC area under the curve was 0.733 at 4 years. Patients in the higher WHR group had a higher body mass index (BMI; 26.7 ± 3.5 vs. 25.4 ± 2.4, P = 0.033) than patients in the lower WHR group. Conclusions: WHR is an independent risk factor of the long-term prognosis of Chinese HF patients with revascularized CHD. Patients with WHR ≥ 0.93 require intensified treatment. Higher WHR is related to higher BMI and ΔVO2/ΔWR.

Volumes of coronary plaque disease in relation to body mass index, waist circumference, truncal fat mass and epicardial adipose tissue in patients with type 2 diabetes mellitus and controls

OBJECTIVES

Coronary atherosclerosis in patients with type 2 diabetes mellitus may be promoted by regional fat distribution. We investigated the association between anthropometric measures of obesity, truncal fat mass, epicardial adipose tissue and coronary atherosclerosis in asymptomatic patients and matched controls.

METHODS

We examined 44 patients and 59 controls [mean (standard deviation) age 64.4 ± 9.9 vs 61.8 ± 9.7, male 50% vs 47%, diabetes duration mean (standard deviation) 7.7 ± 1.5] with coronary computed tomography angiography. Coronary plaques were quantified as total, calcified, non-calcified and low-density non-calcified plaque volumes (mm³). Regional fat distribution was assessed by dual-energy X-ray absorptiometry, body mass index (kg/m²), waist circumference (cm) and epicardial fat volume (mm³). Endothelial function and systemic inflammation were evaluated by peripheral arterial tonometry (log transformed Reactive Hyperemia Index) and C-reactive protein (mg/L).

RESULTS

Body mass index and waist circumference (p < 0.02) were associated with coronary plaque volumes. Body mass index was associated with low-density non-calcified plaque volume after adjustment for age, sex and diabetes status (p < 0.01). Truncal fat mass (p > 0.51), waist circumference (p > 0.06) and epicardial adipose tissue (p > 0.17) were not associated with coronary plaque volumes in adjusted analyses.

CONCLUSION

Body mass index is associated with coronary plaque volumes in diabetic as well as non-diabetic individuals.

An increased waist-to-hip ratio is a key determinant of atherosclerotic burden in overweight subjects

AIMS

The association of overweight status and cardiovascular disease is not clear. In this study we aimed to investigate coronary atherosclerotic disease, evaluated as coronary artery calcium score (CACs), in overweight patients with or without abdominal obesity as defined by waist-to-hip ratio (WHR).

METHODS

We enrolled 276 patients aged between 40 and 70 years, with a body mass index of 25-29.9 kg/m² and at least one cardiovascular risk factor. Exclusion criteria were history of diabetes, cardiovascular or renal disease. Patients were stratified in high WHR (H-WHR) or low WHR (L-WHR) group according to WHR (≥ 0.85 for women and ≥ 0.90 for men) and underwent multi-detector computed tomography for CACs. Mean carotid intima-media thickness (IMT) and plaque presence were equally assessed.

RESULTS

CACs was higher in the H-WHR group compared to L-WHR (9.05 [0.0-83.48] vs 0.0 [0.0-64.7] AU, p < 0.01); the prevalence of CACs > 0 in the H-WHR group was significantly higher than subjects with L-WHR (59.6% vs 38.5%, p < 0.001). Moreover, H-WHR group had higher mean IMT (0.64 [0.56-0.72] vs 0.59 [0.55-0.67] mm, p < 0.05) and higher carotid plaque prevalence (63.7% vs 50.8%, p < 0.05) compared to subjects with L-WHR. Logistic regression showed that H-WHR was associated with presence of CACs and carotid plaque (p < 0.01). In a multiple linear regression, WHR was positively associated with CACs and IMT (p < 0.01).

CONCLUSIONS

H-WHR is a marker of coronary and peripheral atherosclerotic burden in overweight patients.

Anthropometric measures of obesity and renal artery calcification: Results from the Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Renal artery calcium (RAC) has been linked to several cardiovascular disease (CVD) risk factors, including age, male gender, and hypertension. The purpose of this study was to determine whether anthropometric measures of obesity are associated with presence of RAC.

METHODS

We studied 1287 community-dwelling adults enrolled in the Multi-Ethnic Study of Atherosclerosis. Logistic regression models adjusted for CVD risk factors were used to examine body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) as primary predictors of RAC.

RESULTS

Study participants had a mean age of 67.7 years, 55.7% were female, and 36.8% were non-Hispanic White. Prevalence of RAC was 33.3%. WC and WHR as continuous variables were not significant with adjustment. Subjects with high WC, as defined by World Health Organization cut-offs, had significantly higher odds for RAC in the fully adjusted model. BMI and HC were not significantly associated with RAC in any models.

CONCLUSIONS

In this community-based sample of older adults, higher levels of WC are significantly associated with RAC independently of CVD risk factors. Adults who meet World Health Organization criteria for high WC may be at higher risk for complications of calcified atherosclerosis in the renal arteries.

Abdominal obesity is associated with heart disease in dogs

BACKGROUND

The relationship between overall obesity and fat distribution in dogs and the development of heart disease is unclear. In the present study we evaluated the association between overall obesity and fat distribution and clinical heart disease by morphometric and computed tomography (CT)-based measurements. Body condition score (BCS), modified body mass index (MBMI, kg/m2), waist-to-hock-to-stifle distance ratio (WHSDR), waist-to-ilium wing distance ratio (WIWDR), and waist-to-truncal length ratio (WTLR) were compared between dogs with (n = 44) and without (n = 43) heart disease using receiver operating characteristic (ROC) analysis. Intra-abdominal fat (IAF) and subcutaneous fat (SQF) were measured in dogs with (n = 8) and without (n = 9) heart disease at the center of the fourth and fifth lumbar vertebrae by CT.

RESULTS

BCS was similar between heart disease and healthy groups (3.6 ± 0.2 vs. 3.3 ± 0.1, P = 0.126). The following morphometric measurements were greater in the heart disease group compared with healthy canines: MBMI (65.0 ± 4.5 vs. 52.5 ± 3.7 kg/m2, respectively, P = 0.035); WIWDR (4.1 ± 0.1 vs. 3.1 ± 0.1, P < 0.01); and WTLR (1.25 ± 0.04 vs. 1.05 ± 0.04, P < 0.01). However, there was no significant difference in WHSDR (3.6 ± 0.1 vs. 3.7 ± 0.2, P = 0.875). Interestingly, IAF was significantly increased in dogs with heart disease compared with healthy dogs (23.5 ± 1.5% vs. 19.4 ± 1.2%, P = 0.039) whereas SQF was similar between two groups (35.5 ± 2.7% vs. 38.6 ± 3.5%, P = 0.496). Of the five morphometric indices studied, WIWDR and WTLR provided acceptable discrimination for diagnosing heart disease in dogs, with areas under the ROC curve of 0.778 (95% confidence interval [CI]:0.683-0.874) and 0.727 (95% CI:0.619-0.835), respectively.

CONCLUSIONS

Our data indicate that abdominal obesity, rather than overall obesity, is associated with heart disease in dogs. Measurements of both WIWDR and WTLR are particular useful for detection of an abdominal obesity in dogs.

Outcome after neoadjuvant chemoradiation and correlation with nutritional status in patients with locally advanced pancreatic cancer

BACKGROUND

Cancer patients commonly suffer from weight loss since rapid tumor growth can cause catabolic metabolism and depletion of energy stores such as abdominal fat. In locally advanced pancreatic cancer this is even more pronounced due to abdominal pain, fatigue, nausea or malnutrition. In the present article, we quantify this frequently observed weight loss and assess its impact on outcome and survival.

METHODS

Data on demographics, biometrics, toxicity and survival were collected for the last 100 patients treated with neoadjuvant chemoradiation for locally advanced pancreatic cancer at our department (45.0 Gy and boost up to 54.0 Gy plus concurrent and subsequent gemcitabine), and the subcutaneous fat area at the umbilicus level was measured by computer tomography before and after chemoradiation.

RESULTS

After chemoradiation, patients showed a highly statistically significant weight loss and reduction of the subcutaneous fat area. We could determine a very strong correlation of subcutaneous fat area to patient BMI. By categorizing patients according to their BMI based on the WHO classification as slender, normal, overweight and obese, we found improved but not statistically significant survival among obese patients. Accordingly, patients who showed less weight loss tended to survive longer.

CONCLUSIONS

In this study, patients with pancreatic cancer lost weight during chemoradiation and their subcutaneous fat diminished. Changes in subcutaneous fat area were highly correlated with patients' BMI. Moreover, obese patients and patients who lost less weight had an improved outcome after treatment. Although the extent of weight loss was not significantly correlated with survival, the observed trend warrants greater attention to nutritional status in the future.

Association between second-generation antipsychotics and changes in body mass index in adolescents

PURPOSE

To assess the association of second-generation antipsychotics (SGAs) with changes in body mass index (BMI) among adolescents compared with a matched untreated comparison group.

METHODS

A retrospective cohort study was conducted using an electronic medical record database between January 2004 and July 2009. Adolescents (12-19 years old), newly initiated on SGAs formed the exposure group and untreated adolescents formed the comparison group matched (3:1) to the antipsychotic group based on age, gender, and month of index SGA. Both the exposure and comparison groups were followed for slightly more than a year (395 days). Baseline and follow-up BMI were evaluated for both groups and percentage change from baseline BMI to follow-up BMI was calculated. Multivariate linear regression was conducted to assess the impact of SGAs on percent change in follow-up BMI from baseline controlling for demographic characteristics, baseline medications, comorbidities, and other covariates.

RESULTS

The mean percentage increase in follow-up BMI from baseline for antipsychotic group was significantly higher than the comparison group (p < .01). After adjusting for covariates, adolescents on olanzapine had the highest percentage increase in follow-up BMI from baseline (5.84%, 95% confidence interval [CI], 4.07-7.61) followed by aripiprazole (4.36%; 95% CI, 3.08-5.64), risperidone (3.65%; 95% CI, 2.61-4.68), and quetiapine (1.53%; 95% CI, .53-2.52) compared with the comparison group.

CONCLUSION

This study further validates a growing concern of increased BMI in adolescents on SGA therapy.

Fasting glucose, obesity, and coronary artery calcification in community-based people without diabetes

OBJECTIVE

Our objective was to assess whether impaired fasting glucose (IFG) and obesity are independently related to coronary artery calcification (CAC) in a community-based population.

RESEARCH DESIGN AND METHODS

We assessed CAC using multidetector computed tomography in 3,054 Framingham Heart Study participants (mean [SD] age was 50 [10] years, 49% were women, 29% had IFG, and 25% were obese) free from known vascular disease or diabetes. We tested the hypothesis that IFG (5.6-6.9 mmol/L) and obesity (BMI ≥30 kg/m(2)) were independently associated with high CAC (>90th percentile for age and sex) after adjusting for hypertension, lipids, smoking, and medication.

RESULTS

High CAC was significantly related to IFG in an age- and sex-adjusted model (odds ratio 1.4 [95% CI 1.1-1.7], P = 0.002; referent: normal fasting glucose) and after further adjustment for obesity (1.3 [1.0-1.6], P = 0.045). However, IFG was not associated with high CAC in multivariable-adjusted models before (1.2 [0.9-1.4], P = 0.20) or after adjustment for obesity. Obesity was associated with high CAC in age- and sex-adjusted models (1.6 [1.3-2.0], P < 0.001) and in multivariable models that included IFG (1.4 [1.1-1.7], P = 0.005). Multivariable-adjusted spline regression models suggested nonlinear relationships linking high CAC with BMI (J-shaped), waist circumference (J-shaped), and fasting glucose.

CONCLUSIONS

In this community-based cohort, CAC was associated with obesity, but not IFG, after adjusting for important confounders. With the increasing worldwide prevalence of obesity and nondiabetic hyperglycemia, these data underscore the importance of obesity in the pathogenesis of CAC.

Wait list status of pediatric dialysis patients in North America

Kidney transplantation is the treatment of choice for the majority of pediatric patients with end-stage kidney disease. Previous studies demonstrating racial or gender disparities in access to the deceased donor transplant list could not evaluate the impact of medical concerns or patient preference on waitlist status. We undertook a retrospective cohort study using the NAPRTCS registry to begin to determine barriers to wait list registration for kidney transplantation among pediatric dialysis patients. Clinical and demographic factors were compared in listed vs. non-listed patients. Reasons cited for not listing patients were examined by clinical and demographic factors. At dialysis initiation, 88.7% of pediatric dialysis patients were not on the renal transplant wait list. Twelve months after dialysis initiation, 67.1% of pediatric dialysis patients were not on the wait list. The groups least likely to be on the wait list were infants (adjusted OR 0.23, 95% CI 0.16, 0.32) and girls (adjusted OR 0.78, 95% CI 0.67, 0.90) after adjusting for multiple confounders. The reason most often cited for not listing was medical reason for young infants and that the transplant workup was pending for girls. Further study is needed to identify barriers to wait list registration.

Central adiposity associations to carbohydrate and lipid metabolism in individuals with complete motor spinal cord injury

Altered body composition has been suggested as a major factor for the high prevalence of impaired glucose tolerance, insulin resistance, and dyslipidemia in individuals with spinal cord injury (SCI). The contributions of visceral adipose tissue (VAT), trunk subcutaneous adipose tissue (SAT), and the VAT/SAT ratio to these metabolic derangements in SCI are poorly defined. Thirteen individuals with traumatic motor complete SCI underwent a metabolic study after overnight fasting to measure plasma glucose, insulin, and lipid concentrations. Fast spin echo magnetic resonance imaging was used to quantify the average cross-sectional area (CSA), volumes, and percentages of VAT and SAT across multiaxial slices. Dual-energy x-ray absorptiometry was performed to measure whole-body fat-free mass and fat mass. Visceral adipose tissue CSA was positively related to fasting plasma glucose (r = 0.77, P = .002) and to the ratio of cholesterol to high-density lipoproteins (HDL-C) (r = 0.71, P = .006). Visceral adipose tissue volume was related to total cholesterol (r = 0.57, P = .043) and to low-density lipoproteins (r = 0.59, P = .032). Trunk %SAT was negatively related to glucose concentration and area under the curve (both, r = -0.61, P = .026). Fasting plasma insulin was negatively related to the VAT CSA and VAT/SAT ratio (both, r = -0.57, P = .043). Partial correlations showed a negative association between trunk %SAT and glucose area under the curve (r = -0.61, P = .02) and a positive association with HDL-C (r = 0.64, P = .033). The findings suggest that an increase in VAT, SAT, and VAT/SAT is associated with the adverse metabolic profile commonly seen in individuals with SCI. Trunk %SAT is associated with a reduced risk of glucose intolerance and an increased HDL-C.

Appendicitis, Body Mass Index, and CT: Is CT More Valuable for Obese Patients than Thin Patients?

The purpose of our study is to determine whether body mass index (BMI = weight in kg/height in meters2) was related to the rate of negative appendectomy in patients who underwent preoperative CT. A surgical database search performed using the procedure code for appendectomy identified 925 patients at least 18 years of age who underwent urgent appendectomy between January 1998 and September 2007. BMI was computed for the 703 of these 925 patients for whom height and weight information was available. Patients were stratified based on body mass index (BMI 15-18.49 = underweight; 18.5-24.9 = normal weight; 25–29.9 = overweight; 30-39.9 = obese; > 40 = morbidly obese). Negative appendectomy rates were computed. Negative appendectomy rates for patients who did and did not undergo preoperative CT were 27 per cent and 50 per cent for underweight patients, 10 per cent and 15 per cent for normal weight patients, 12 per cent and 17 per cent for overweight patients, 7 per cent and 30 per cent for obese patients, and 10 per cent and 100 per cent for morbidly obese patients. The difference in negative appendectomy rates for overweight patients, obese patients, and morbidly obese patients who underwent preoperative CT as compared with patients in the same BMI category who did not undergo preoperative CT was statistically significant ( P ≤ 0.001). The negative appendectomy rates for overweight patients, obese patients, and morbidly obese patients who underwent preoperative CT were significantly lower than for patients in these same BMI categories who did not undergo preoperative CT.

Influence of motor complete spinal cord injury on visceral and subcutaneous adipose tissue measured by multi-axial magnetic resonance imaging

OBJECTIVE

Abdominal obesity conveys substantial health risks, in association with high levels of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and an increased proportion of VAT to SAT. The purposes were to determine the influence of spinal cord injury (SCI) on the associations between single axial cross-sectional area (CSA) slices and the average CSA or volumes of VAT and SAT across multi-axial slices of magnetic resonance imaging (MRI); and the relationships relative to the whole body composition and anthropometrics.

METHODS

Thirteen healthy male participants with traumatic motor complete SCI underwent fast spin-echo MRI to measure VAT and SAT across multi-axial slices, followed by dual-energy X-ray absorptiometry to measure whole body fat-free mass (FFM) and fat mass (FM). Waist circumference (WC) was also measured in the seated position.

RESULTS

The trunk CSAs of VAT and SAT were 99 +/- 51 and 164 +/- 69 cm2, respectively, and the ratio of VAT to SAT was 0.68 +/- 0.33. The CSAs of VAT and SAT at a single slice strongly predicted the average CSA and modestly predicted the volumes across multi-axial slices. VAT and SAT represented 5.7 +/- 1.8% and 9.7 +/- 3.2% of the total body FM, respectively. Percent body FFM was negatively related to VAT and SAT volumes, but not to a single axial CSA.

CONCLUSION

A single slice CSA can modestly predict the volume of multi-axial slices in individuals with SCI, yet it is not related to any of the body composition variables. Increased percent FFM is associated with a reduction in VAT and SAT volumes measured across multi-axial slices. The ratio of VAT to SAT is greater than 0.4, suggesting that individuals with SCI are at high risk of developing metabolic sequelae.

Association of coronary artery calcification with obstructive sleep apnea and obesity in middle-aged men

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) and obesity are closely associated, and both have been reported to increase the risk of coronary heart disease. Although obesity is known to be associated with coronary artery calcification (CAC), there is limited information on whether OSA is associated with CAC independent of obesity.

METHODS AND RESULTS

A cross-sectional study examined the association between OSA and CAC among 258 healthy men, ages 40-49 years old, randomly selected from a population-based cohort. All individuals underwent overnight polysomnography and electron-beam computed tomography to measure their apnea-hypopnea index (AHI) and degree of CAC. A logistic regression model including potential cardiovascular risk factors excluding body mass index (BMI) showed that the presence of CAC was significantly greater in the fourth quartile versus the first quartile of AHI severity (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.01-4.86). A multivariate linear regression model excluding BMI also showed that AHI was significantly associated with CAC (P = 0.004). However, this association was no longer significant after adjusting for BMI.

CONCLUSIONS

In our cross-sectional study, even though both OSA and obesity were positively associated with the presence and extent of CAC, only obesity remained a significant independent contributor after an adjustment for potential cardiovascular risk factors, irrespective of OSA.

Differential associations of weight dynamics with coronary artery calcium versus common carotid artery intima-media thickness: The CARDIA Study

Change and fluctuation in body mass index (BMI; weight (kg)/height (m)(2)) may be associated differently with coronary artery calcification (CAC) than with carotid artery intima-media thickness (IMT). The authors analyzed data on 2,243 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, initially aged 18-30 years, who were examined every 2-5 years over a 20-year period (1985-2006). BMI at year 0 was associated positively and linearly with CAC at year 20; however, the association of BMI with year 20 CAC became progressively U-shaped in subsequent examinations (years 10, 15, and 20). To understand the deepening U shape, the authors modeled year 20 BMI and its history using 3 indices: year 0 BMI, linear slope of BMI during 20 years, and BMI fluctuation during 20 years. In models including these 3 terms, year 0 BMI was associated positively with CAC, as was BMI fluctuation. However, adjusted odds ratios across quintiles of BMI slope (vs. the lowest quintile) were 0.7, 0.4, 0.5, and 0.4 (P(trend) < 0.01), suggesting higher risk of CAC with weight loss, plateauing after moderate weight gain. In contrast, IMT was associated positively with BMI at all examinations and with 20-year BMI slope and was unassociated with BMI fluctuation. Surprisingly, CAC risk was higher with BMI loss and lower with BMI gain, whereas associations with IMT were as expected.

Is obesity a further cardiovascular risk factor in patients with erectile dysfunction?

INTRODUCTION

Erectile dysfunction (ED) and, in particular, arteriogenic ED have been proposed as new markers of risk for incident major adverse cardiovascular events (MACE). Reduced penile blood flow is more common in obese people than in leaner ED subjects.

AIM

To explore the interaction of overweight/obesity and penile blood flow in the prediction of incident MACE.

METHODS

This is an observational prospective cohort study evaluating a consecutive series of 1,687 patients attending our andrological unit for ED. Different clinical, biochemical, and instrumental (penile flow at color Doppler ultrasound: PCDU) parameters were evaluated.

MAIN OUTCOMES MEASURES

According to body mass index (BMI), subjects were divided into three groups: normal weight (BMI = 18.5-24.9 kg/m(2)), overweight (BMI = 25.0-29.9 kg/m(2)), and obese (BMI >or= 30.0 kg/m(2)). Information on MACE was obtained through the City of Florence Registry Office.

RESULTS

Among patients studied, 39.8% were normal weight, while 44.1% and 16.1% showed BMI 25-29.9 and 30 kg/m(2) or higher, respectively. During a mean follow-up of 4.3 +/- 2.6 years, 139 MACE, 15 of which were fatal, were observed. Cox regression model, after adjusting for age and Chronic Diseases Score, showed that obesity classes along with the presence of arteriogenic ED (peak systolic velocity at PCDU <25 cm/second) were significantly and independently associated with incident MACE (hazard ratio = 1.47 [1.1-1.95], P < 0.05 and 2.58 [1.28-5.09], P < 0.001, respectively). When a separate analysis was performed for classes of obesity, reduced peak systolic velocity at PCDU (<25 cm/second) was significantly associated with incident MACE in obese (BMI >or= 30 kg/m(2)), but not in leaner, subjects.

CONCLUSIONS

In obese subjects, more than in leaner ED subjects, impaired penile blood flow is associated with an increased risk of incident cardiovascular disease. The interaction with concomitant risk factors, such as obesity, should be taken into account when assessing the predictive value of penile blood flow for cardiovascular diseases.

Impact of body mass index on the incidence of cardiometabolic risk factors in ambulatory care settings over 5 years or more

OBJECTIVE

This study was performed to evaluate the association of body mass index (BMI) with the incidence of cardiometabolic risk factors in ambulatory care electronic medical records (EMRs) over 5 years or more.

DESIGN

A retrospective cohort of normal versus obese patients.

SUBJECTS

Subjects>or=18 years were identified between 1996 and 2005.

MEASUREMENTS

Patients were categorized as either normal weight (18 kg/m2<BMI<or=27 kg/m2) or obese (BMI>27 kg/m2) based on baseline BMI (measured 395 days or more after first EMR activity). Outcomes included development, at least 180 days after the first BMI reading date, of four cardiometabolic risk factors (elevated triglycerides, low high-density lipoprotein cholesterol [HDL-C], hypertension, or type 2 diabetes) determined from ICD-9 code, prescribed drug, or biometric reading. Logistic regression estimated the odds of developing cardiometabolic risk factors, alone and combined for normal versus obese patients forward for at least 5 years.

RESULTS

Seventy-one percent were female, mean age was 43.5 years, and 37.6% had a baseline BMI>27 kg/m2. Comparing obese versus normal weight patients, adjusted odds ratios for the incidence of elevated triglycerides, hypertension, diabetes, and low HDL-C were 2.1 (95% confidence interval [95% CI] 1.9-2.3), 2.2 (95% CI 2.1-2.4), 2.3 (95% CI 2.0-2.7), and 2.2 (95% CI 2.0-2.4), respectively. Adjusted odds ratios of developing one and all four new risk factors were 1.9 (95% CI 1.8-2.1) and 7.9 (95% CI 5.9-10.5), respectively.

CONCLUSION

Obese patients are approximately twice as likely to develop cardiometabolic risk factors compared with those having normal weight over 5 or more years.

Comparison between high-sensitivity C-reactive protein (hs-CRP) and white blood cell count (WBC) as an inflammatory component of metabolic syndrome in Japanese

OBJECTIVE

To compare two systemic inflammatory markers, high-sensitivity C-reactive protein (hs-CRP) and white blood cell count (WBC), as a component of metabolic syndrome (MetS).

METHODS

Data of hs-CRP and WBC from 2,185 Japanese men and 1,383 Japanese women were examined using receiver operating characteristic (ROC) curve for diagnosing MetS and Spearman's correlation coefficients.

RESULTS

The area under ROC curve (AUC) of hs-CRP was 0.71 in men and 0.74 in women. The AUC of WBC was 0.65 in men and 0.69 in women. The optimal cutoff point (sensitivity; specificity) of hs-CRP was 0.40 mg/L (0.69; 0.65) in men and 0.35 mg/L (0.67; 0.72) in women. The optimal cutoff point (sensitivity; specificity) of WBC was 5,600/L(-6) (0.61; 0.61) in men and 5,000/L(-6) (0.65; 0.63) in women. Correlations between obesity parameters, blood pressure, and liver function tests were stronger with hs-CRP than with WBC. But, no correlation between MetS-related risk factors was stronger with WBC than with hs-CRP.

CONCLUSION

Hs-CRP is superior to WBC as an inflammatory component of MetS in Japanese. However, WBC may be useful when hs-CRP is not available because WBC is routinely measured in clinical practice.

Comparison among body mass index (BMI), waist circumference (WC), and percent body fat (%BF) as anthropometric markers for the clustering of metabolic risk factors in Japanese

OBJECTIVE

To compare body mass index (BMI), waist circumference (WC), and percent body fat (%BF) as markers for the clustering of metabolic risk factors in Japanese.

METHODS

Age-adjusted correlation coefficients (Rs) were calculated between the three anthropometric markers of obesity and metabolic risk factors in 2,444 men and 1,442 women among Japanese. Areas under receiver operating characteristic curves (AUCs) of BMI, WC, and %BF were calculated for diagnosing the clustering of 1 or more, 2 or more, 3 or more, and 4 risk factors among increased blood pressure, impaired fasting glucose, increased triglycerides, and decreased HDL cholesterol and for the clustering of 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, and 6 risk factors among the upper four risk factors as well as increased high-sensitivity C-reactive protein and increased LDL cholesterol.

RESULTS

The Rs were not significantly different among BMI, WC, and %BF except for the difference between the R of BMI (0.217) and that of %BF (0.283) with LDL cholesterol in men (p=0.014). The AUCs of BMI, WC, and %BF for diagnosing any of the risk factor clustering patterns defined above were not significantly different in both men and women.

CONCLUSION

The AUCs for diagnosing the clustering of metabolic risk factors were not significantly different among BMI, WC, and %BF.

A prospective study of abdominal obesity and coronary artery calcium progression in older adults

OBJECTIVE

Little is known about obesity measurements and coronary artery calcium (CAC) progression in older adults. We examined the sex-specific association between measures of body size and fat distribution with CAC progression.

SUBJECTS AND METHODS

Participants were 156 men and 182 women (mean age 67 yr) without known heart disease who had electron-beam computed tomography for CAC at baseline and again 4.5 yr later. Obesity assessments were weight, height, body mass index, waist and hip circumference, waist to hip ratio, waist to height ratio, sc and visceral adipose tissue (SAT, VAT), and SAT to VAT ratio based on abdominal electron-beam computed tomography. CAC progression was defined as categorical (square root increased on total CAC volume score > or = 2.5 mm(3)) and continuous variables.

RESULTS

During the follow-up, 55% of men and 38.5% of women had CAC progression. Increased waist to hip ratio (> or = 0.9 for men, > or = 0.85 for women) and waist to height ratio (> or = 0.55 for men, > or = 0.54 for women) were positively and independently associated with CAC progression [median (interquartile range)] [60.8 (145) vs. 10.8 (56) mm(3), P = 0.002 and 50 (153) vs. 22(84) mm(3), P = 0.03, respectively]. In women but not men, an increased waist circumference (> 88 cm) independently predicted CAC progression (odds ratio 3.0 95% confidence interval 1.03-8.0, P = 0.04), whereas VAT to SAT ratio predicted CAC progression in men but not women (odds ratio 2.8 95% confidence interval 1.01-7.8, P = 0.04).

CONCLUSION

In this study of older adults without known heart disease, abdominal obesity was an independent predictor of CAC progression. These results point to the importance of using clinical measurements of abdominal obesity to identify individuals at increased risk for atherosclerosis.

Comparative relation of general, central, and visceral adiposity measures for coronary artery calcium in subjects without previous coronary events

It is unclear whether visceral obesity is largely responsible for an increased risk of coronary artery disease. In the present study, 1,054 men underwent coronary artery calcium (CAC) scoring and abdominal computed tomography. Risk factor information, body mass index, waist circumference, and waist-to-hip ratio were collected for all participants. The total fat, visceral fat, and subcutaneous fat areas were also quantified at the level of the umbilicus using computed tomography. We then investigated the association of these obesity parameters with the CAC score. Participants with a CAC score >10 had a larger waist circumference (97 +/- 12 vs 95 +/- 12 cm, p <0.001), a larger total fat area (434 cm(2), interquartile range 339 to 565, vs 415 cm(2), interquartile range 315 to 521; p = 0.005), a larger visceral fat area (200 cm(2), interquartile range 143 to 256, vs 175 cm(2), interquartile range 124 to 225; p <0.001), and a greater waist-to-hip ratio (0.93 +/- 0.07 vs 0.91 +/- 0.07, p <0.001) than those with a CAC score of < or =10. Those with a CAC score >10 also tended to have a greater body mass index and larger subcutaneous fat area. After adjusting for traditional cardiovascular risk factors, however, only a large waist circumference (odds ratio 1.5, 95% confidence interval 1.04 to 2.0), a high total fat area (odds ratio 1.5, 95% confidence interval 1.1 to 2.1), and a high waist-to-hip ratio (odds ratio 1.6, 95% confidence interval 1.2 to 2.3) remained significantly associated with a CAC score >10. In conclusion, the measures of central obesity were more strongly associated with the CAC score than either the parameters assessing overall obesity or other more direct measures of visceral adiposity. These findings suggest that the total amount of central obesity is more important than the relative distribution of visceral versus subcutaneous fat.

Carotid arterial elasticity is a sensitive atherosclerosis value reflecting visceral fat accumulation in obese subjects

BACKGROUND

We previously reported the arterial elasticity value we measured to reflect the characteristic features of vessel walls, and to possibly be useful for detecting early stage atherosclerosis in type 2 diabetes. Obesity, especially visceral adiposity, is well known to play a crucial role in the development of metabolic disorders and atherosclerosis. To assess whether arterial elasticity value reflects the effect of obesity on atherosclerosis, we examined the associations of obesity characteristics with atherosclerosis values including arterial elasticity, carotid intima-media thickness (IMT) and pulse wave velocity (PWV).

METHODS

Three atherosclerosis values were measured in 78 obese subjects (body mass index >/=30). We investigated the associations of atherosclerosis values with obesity-related parameters including abdominal fat accumulation determined by computed tomography.

RESULTS

Arterial elasticity values were positively related to established atherosclerosis values, carotid IMT and PWV, in obese subjects. Age, systolic blood pressure and hypertension also correlated with these atherosclerosis values. Single regression analysis showed all three atherosclerosis values to correlate significantly with visceral fat area. Intriguingly, visceral fat area is an independent variable affecting arterial elasticity, but not IMT or PWV. Furthermore, multiple regression analysis revealed that arterial elasticity correlates strongly with visceral fat area.

CONCLUSIONS

Arterial elasticity value we measure is a new parameter for evaluating atherosclerosis in subjects with visceral adiposity and more sensitive than the currently established atherosclerosis values, carotid IMT and PWV. Measuring arterial elasticity has the potential to reveal minute vascular changes, and may have broad clinical applications for evaluating early stage atherosclerosis.

Menopause, the metabolic syndrome, and mind-body therapies

Cardiovascular disease risk rises sharply with menopause, likely due to the coincident increase in insulin resistance and related atherogenic changes that together comprise the metabolic or insulin resistance syndrome, a cluster of metabolic and hemodynamic abnormalities strongly implicated in the pathogenesis and progression of cardiovascular disease. A growing body of research suggests that traditional mind-body practices such as yoga, tai chi, and qigong may offer safe and cost-effective strategies for reducing insulin resistance syndrome-related risk factors for cardiovascular disease in older populations, including postmenopausal women. Current evidence suggests that these practices may reduce insulin resistance and related physiological risk factors for cardiovascular disease; improve mood, well-being, and sleep; decrease sympathetic activation; and enhance cardiovagal function. However, additional rigorous studies are needed to confirm existing findings and to examine long-term effects on cardiovascular health.

The impact of obesity on cardiovascular disease risk factors and subclinical vascular disease: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

To assess the importance of the obesity epidemic on cardiovascular disease (CVD) risk, we determined the prevalence of obesity and the relationship of obesity to CVD risk factors and subclinical vascular disease.

METHODS

The Multi-Ethnic Study of Atherosclerosis is an observational cohort study involving 6814 persons aged 45 to 84 years who were free of clinical CVD at baseline (2000-2002). The study assessed the association between body size and CVD risk factors, medication use, and subclinical vascular disease (coronary artery calcium, carotid artery intimal medial thickness, and left ventricular mass).

RESULTS

A large proportion of white, African American, and Hispanic participants were overweight (60% to 85%) and obese (30% to 50%), while fewer Chinese American participants were overweight (33%) or obese (5%). Hypertension and diabetes were more prevalent in obese participants despite a much higher use of antihypertensive and/or antidiabetic medications. Obesity was associated with a greater risk of coronary artery calcium (17%), internal carotid artery intimal medial thickness greater than 80th percentile (32%), common carotid artery intimal medial thickness greater than 80th percentile (45%), and left ventricular mass greater than 80th percentile (2.7-fold greater) compared with normal body size. These associations persisted after adjustment for traditional CVD risk factors.

CONCLUSIONS

These data confirm the epidemic of obesity in most but not all racial and ethnic groups. The observed low prevalence of obesity in Chinese American participants indicates that high rates of obesity should not be considered inevitable. These findings may be viewed as indicators of potential future increases in vascular disease burden and health care costs associated with the obesity epidemic.

Visceral adiposity and subclinical coronary artery disease in elderly adults: Rancho Bernardo Study

OBJECTIVE

Despite growing attention to central obesity as a predictor of clinical coronary heart disease (CHD), there are few reports about the association between directly measured visceral obesity and subclinical coronary atherosclerosis in elderly adults. We examined this association in elderly, community-dwelling adults without clinically recognized CHD.

METHODS AND PROCEDURES

Elderly adults (190 men, BMI 27.2 +/- 3.6 kg/m(2); 220 women, BMI 25.8 +/- 4.6) aged 55-88 years (median 69 years) with no history of CHD or coronary revascularization had an electron beam computed tomography (EBCT) to measure coronary artery calcification score (CACS), an estimate of coronary plaque burden. Visceral and subcutaneous adiposity were assessed by a triple-slice EBCT scan at the lumbar 4-5 disc level and height, weight, and waist and hip circumferences were measured.

RESULTS

In sex-specific ordinal logistic regression analyses, no measure of obesity or body fat distribution, including BMI, waist-to-hip ratio, waist girth, and visceral and subcutaneous fat by EBCT, was significantly associated with CACS before or after adjusting for multiple covariates of CACS (age, smoking, alcohol intake, exercise, pulse pressure, low-density lipoprotein (LDL)/high-density lipoprotein (HDL)-cholesterol ratio, and fasting plasma glucose).

DISCUSSION

In elderly adults without clinically recognized CHD, body weight and fat distribution do not predict coronary artery plaque burden. These results raise questions about the value of weight reduction diets for preventing heart disease in elderly survivors without clinical heart disease.

Visceral adipose tissue, a potential risk factor for carotid atherosclerosis: results of the Multicultural Community Health Assessment Trial (M-CHAT)

BACKGROUND AND PURPOSE

The association between abdominal obesity and atherosclerosis is believed to be due to excess visceral adipose tissue (VAT), which is associated with traditional risk factors. We hypothesized that VAT is an independent risk factor for atherosclerosis.

METHODS

Healthy men and women (N=794) matched for ethnicity (aboriginal, Chinese, European, and South Asian) and body mass index range (<25, 25 to 29.9, or > or =30 kg/m(2)) were assessed for VAT (by computed tomography scan), carotid atherosclerosis (by ultrasound), total body fat, cardiovascular risk factors, lifestyle, and demographics.

RESULTS

VAT was associated with carotid intima-media thickness (IMT), plaque area, and total area (IMT area and plaque area combined) after adjusting for demographics, family history, smoking, and percent body fat in men and women. In men, VAT was associated with IMT and total area after adjusting for insulin, glucose, homocysteine, blood pressure, and lipids. This association remained significant with IMT after further adjustment for either waist circumference or the waist-to-hip ratio. In women, VAT was no longer associated with IMT or total area after adjusting for risk factors.

CONCLUSIONS

VAT is the primary region of adiposity associated with atherosclerosis and likely represents an additional risk factor for carotid atherosclerosis in men. Most but not all of this risk can be reflected clinically by either the waist circumference or waist-hip ratio measures.

The Association of Differing Measures of Overweight and Obesity With Prevalent Atherosclerosis

OBJECTIVES

This study sought to evaluate the associations between different measures of obesity and prevalent atherosclerosis in a large population-based cohort.

BACKGROUND

Although obesity is associated with cardiovascular mortality, it is unclear whether this relationship is mediated by increased atherosclerotic burden.

METHODS

Using data from the Dallas Heart Study, we assessed the association between gender-specific obesity measures (i.e., body mass index [BMI]; waist circumference [WC]; waist-to-hip ratio [WHR]) and prevalent atherosclerosis defined as coronary artery calcium (CAC) score >10 Agatston units measured by electron-beam computed tomography and detectable aortic plaque measured by magnetic resonance imaging.

RESULTS

In univariable analyses (n = 2,744), CAC prevalence was significantly greater only in the fifth versus first quintile of BMI, whereas it increased stepwise across quintiles of WC and WHR (p trend <0.001 for each). After multivariable adjustment for standard risk factors, prevalent CAC was more frequent in the fifth versus first quintile of WHR (odds ratio 1.91, 95% confidence interval 1.30 to 2.80), whereas no independent positive association was observed for BMI or WC. Similar results were observed for aortic plaque in both univariable and multivariable-adjusted analyses. The c-statistic for discrimination of prevalent CAC was greater for WHR compared with BMI and WC in women and men (p < 0.001 vs. BMI; p < 0.01 vs. WC).

CONCLUSIONS

We discovered that WHR was independently associated with prevalent atherosclerosis and provided better discrimination than either BMI or WC. The associations between obesity measurements and atherosclerosis mirror those observed between obesity and cardiovascular mortality, suggesting that obesity contributes to cardiovascular mortality via increased atherosclerotic burden.

Early experimental obesity is associated with coronary endothelial dysfunction and oxidative stress

Obesity is independently associated with increased cardiovascular risk. However, since established obesity clusters with various cardiovascular risk factors, configuring the metabolic syndrome, the early effects of obesity on vascular function are still poorly understood. The current study was designed to evaluate the effect of early obesity on coronary endothelial function in a new animal model of swine obesity. As to method, juvenile domestic crossbred pigs were randomized to either high-fat/high-calorie diet (HF) or normal chow diet for 12 wk. Coronary microvascular permeability and abdominal wall fat were determined by using electron beam computerized tomography. Epicardial endothelial function and oxidative stress were measured in vitro. Systemic oxidative stress, renin-angiotensin activity, leptin levels, and parameters of insulin sensitivity were evaluated. As a result, HF pigs were characterized by abdominal obesity, hypertension, and elevated plasma lysophosphatidylcholine and leptin in the presence of increased insulin sensitivity. Coronary endothelium-dependent vasorelaxation was reduced in HF pigs and myocardial microvascular permeability increased compared with those values in normal pigs. Systemic redox status in HF pigs was similar to that in normal pigs, whereas the coronary endothelium demonstrated higher content of superoxide anions, nitrotyrosine, and NADPH-oxidase subunits, indicating increased tissue oxidative stress. In conclusion, the current study shows that early obesity is characterized by increased vascular oxidative stress and endothelial dysfunction in association with increased levels of leptin and before the development of insulin resistance and systemic oxidative stress. Vascular dysfunction is therefore an early manifestation of obesity and might contribute to the increased cardiovascular risk, independently of insulin resistance.

Progression of Subclinical Coronary Atherosclerosis

Background— Obesity is associated with coronary artery calcification (CAC), a marker of the presence and extent of subclinical coronary atherosclerosis. Obesity adds incremental information in identifying those at higher risk of coronary heart disease to traditional risk factor assessment. The present study examined associations between obesity measures and progression of CAC in those at higher (≥10%) and lower (<10%) 10-year coronary heart disease risk according to the Framingham risk equation.

Methods and Results— In this study, 443 asymptomatic white individuals >30 years of age (243 men) had baseline and follow-up CAC measurements an average of 8.9 years apart. Multivariable linear regression models were fit to determine associations of obesity measures at baseline with progression of CAC defined as log e of the difference between follow-up and baseline CAC area plus 1 divided by time (in years) between examinations, adjusting for baseline CAC quantity, age, sex, baseline hypertension status, and baseline cholesterol level. Among 329 participants (74.3%) in the lower-risk group, waist circumference ( P =0.024), waist-to-hip ratio ( P <0.001), body mass index ( P =0.036), and being overweight compared with being underweight or of normal weight ( P =0.008) were each significantly positively associated with progression of CAC. Among those at higher coronary heart disease risk, no baseline obesity measures were associated with CAC progression.

Conclusions— Various measures of obesity were associated with increased progression of CAC in those at lower risk of coronary heart disease. Future studies examining the effectiveness of weight reduction strategies in reducing CAC progression among those with an otherwise favorable risk factor profile may be warranted.