Wide Range Of Body Mass Index Research Articles

Age and body mass index associations with body segment parameters

Body segment parameters (BSPs) such as segment mass, center of mass, and radius of gyration are required in many ergonomic tools and biomechanical models to estimate injury risk, and quantify muscle and joint contact forces. Currently, the full effects of age and obesity have not been taken into account when predicting BSPs. The goal of this study is to quantify the impact of body mass index (BMI) and age on BSPs, in order to provide more representative measures necessary for modeling inputs. A whole body dual energy X-ray absorptiometry (DXA) scan was collected for 280 working men and women with a wide range of BMI and aged 21 to 70 years. Established DXA processing methods were used to determine in-vivo estimates of the mass, center of mass, and radius of gyration for the upper arm, forearm, torso, thigh, and shank for males and females. Regression models were used to determine if age and BMI terms, as well as their interactions, were associated with these BSPs. The variability in BSPs explained by BMI alone ranged from 4 to 51%, and age explained an additional 3–19%. Thus, BMI and age are significant correlates of BSPs, and need to be taken into account when predicting certain BSPs in order to obtain accurate and representative results in biomechanical models.

Net Acid Excretion and Urinary Organic Anions in Idiopathic Uric Acid Nephrolithiasis.

Idiopathic uric acid nephrolithiasis, which is closely associated with obesity and the metabolic syndrome, is increasing in prevalence. Unduly acidic urine pH, the quintessential pathophysiologic feature of this disease, is in part explained by inadequate excretion of the principal urinary buffer ammonium. The role of net acid excretion in the pathogenesis of uric acid nephrolithiasis is incompletely understood. We compared acid-base parameters of patients with idiopathic uric acid nephrolithiasis with matched control subjects under controlled diets in an inpatient metabolic unit. Measurements included fasting blood and 24-hour urine chemistries and 24-hour urine metabolomic analysis. Comparisons between groups included analysis of covariance models controlling for urine pH or body mass index. Subjects with idiopathic uric acid nephrolithiasis had lower urine pH (5.5 versus 5.9; P<0.001) and higher net acid excretion (60 versus 43 mEq/24 h; P<0.001), with the excess H+ carried by nonammonium buffers. In all subjects, there was a positive relationship of net acid excretion with higher body mass index in spite of strictly controlled equivalent dietary acid intake. This relationship was most evident among control subjects (r=0.36; P=0.03). It was attenuated in patients with idiopathic uric acid nephrolithiasis whose net acid excretion remained fixedly high and ammonium excretion remained low relative to net acid excretion, resulting in low urine pH over a wide body mass index range. Urinary metabolomics was performed to attempt to identify excess organic acids presented to the kidney in idiopathic uric acid nephrolithiasis. Among the tricarboxylic acid cycle intermediates and amino acid and lipid metabolites analyzed, 26 organic anions with acid dissociation constants values in the range of urine pH showed greater protonation. However, protons carried by the identified organic acids did not entirely account for the higher titratable acidity seen in idiopathic uric acid nephrolithiasis. Higher acid load to the kidney, resulting in higher urinary net acid excretion, is an important factor in the pathogenesis of idiopathic uric acid nephrolithiasis.

Ethnic differences in fat and muscle mass and their implication for interpretation of bioelectrical impedance vector analysis

According to the World Health Organization Expert Consultation, current body mass index (BMI) cut-offs should be retained as an international classification. However, there are ethnic differences in BMI-associated health risks that may be caused by differences in body fat or skeletal muscle mass and these may affect the interpretation of phase angle and bioelectrical impedance vector analysis (BIVA). Therefore, the aim of this study was to compare body composition measured by bioelectrical impedance analysis among 1048 German, 1026 Mexican, and 995 Japanese adults encompassing a wide range of ages and BMIs (18-78 years; BMI, 13.9-44.3 kg/m2). Regression analyses between body composition parameters and BMI were used to predict ethnic-specific reference values at the standard BMI cut-offs of 18.5, 25, and 30 kg/m2. German men and women had a higher fat-free mass per fat mass compared with Mexicans. Normal-weight Japanese were similar to Mexicans but approached the German phenotype with increasing BMI. The skeletal muscle index (SMI, kg/m2) was highest in Germans, whereas in BIVA, the Mexican group had the longest vector, and the Japanese group had the lowest phase angle and the highest extracellular/total body water ratio. Ethnic differences in regional partitioning of fat and muscle mass at the trunk and the extremities contribute to differences in BIVA and phase angle. In conclusion, not only the relationship between BMI and adiposity is ethnic specific; in addition, fat distribution, SMI, and muscle mass distribution vary at the same BMI. These results emphasize the need for ethnic-specific normal values in the diagnosis of obesity and sarcopenia.

Copy number of pancreatic polypeptide receptor gene NPY4R correlates with body mass index and waist circumference.

Multiple genetic studies have linked copy number variation (CNV) in different genes to body mass index (BMI) and obesity. A CNV on chromosome 10q11.22 has been associated with body weight. This CNV region spans NPY4R, the gene encoding the pancreatic polypeptide receptor Y4, which has been described as a satiety-stimulating receptor. We have investigated CNV of the NPY4R gene and analysed its relationship to BMI, waist circumference and self-reported dietary intake from 558 individuals (216 men and 342 women) representing a wide BMI range. The copy number for NPY4R ranged from 2 to 8 copies (average 4.6±0.8). Rather than the expected negative correlation, we observed a positive correlation between NPY4R copy number and BMI as well as waist circumference (r = 0.267, p = 2.65×10−7 and r = 0.256, p = 8×10−7, respectively). Each additional copy of NPY4R correlated with 2.6 kg/m2 increase in BMI and 5.67 cm increase in waist circumference (p = 3.3×10−7 and p = 1×10−6, respectively) for women. For men, there was no statistically significant correlation between CNV and BMI. Our results suggest that NPY4R genetic variation influences body weight in women, but the exact role of this receptor appears to be more complex than previously proposed.

Effects of resveratrol on memory performance, hippocampus connectivity and microstructure in older adults – A randomized controlled trial

IntroductionThe polyphenol resveratrol has been suggested to exert beneficial effects on memory and the aging hippocampus due to calorie-restriction mimicking effects. However, the evidence based on human interventional studies is scarce. We therefore aimed to determine the effects of resveratrol on memory performance, and to identify potential underlying mechanisms using a broad array of blood-based biomarkers as well as hippocampus connectivity and microstructure assessed with ultra-high field magnetic resonance imaging (UHF-MRI). MethodsIn this double-blind, randomized controlled trial, 60 elderly participants (60–79 years) with a wide body-mass index (BMI) range of 21–37 kg/m2 were randomized to receive either resveratrol (200 mg/day) or placebo for 26 weeks (registered at ClinicalTrials.gov: NCT02621554). Baseline and follow-up assessments included the California Verbal Learning Task (CVLT, main outcome), the ModBent task, anthropometry, markers of glucose and lipid metabolism, inflammation and neurotrophins derived from fasting blood, multimodal neuroimaging at 3 and 7 T, and questionnaires to assess confounding factors. ResultsMultivariate repeated-measures ANOVA did not detect significant time by group effects for CVLT performance. There was a trend for preserved pattern recognition memory after resveratrol, while performance decreased in the placebo group (n.s., p = 0.07). Further exploratory analyses showed increases in both groups over time in body fat, cholesterol, fasting glucose, interleukin 6, high sensitive C-reactive protein, tumor necrosis factor alpha and in mean diffusivity of the subiculum and presubiculum, as well as decreases in physical activity, brain-derived neurotrophic factor and insulin-like growth factor 1 at follow-up, which were partly more pronounced after resveratrol. DiscussionThis interventional study failed to show significant improvements in verbal memory after 6 months of resveratrol in healthy elderly with a wide BMI range. A non-significant trend emerged for positive effects on pattern recognition memory, while possible confounding effects of unfavorable changes in lifestyle behavior, neurotrophins and inflammatory markers occurred. Our findings also indicate the feasibility to detect (un)healthy aging-related changes in measures of hippocampus microstructure after 6 months using 7T diffusion MRI. More studies incorporating a longer duration and larger sample size are needed to determine if resveratrol enhances memory performance in healthy older adults.

Salivary adiponectin concentration in healthy adult males in relation to anthropometric measures and fat distribution.

Body fat content, fat distribution, and adiponectin level are important variables in the development of obesity related complications. Anthropometric indices may provide an economic and faster method in measuring the risk for complications through their predictive effect of fat distribution and adiponectin concentration. We aimed to determine, which of the waist circumference (WC), waist-to-hip ratio (WHR), and body mass index (BMI) may be the best predictor for the total fat percentage (WF), visceral fat level (VF), and subcutaneous whole-body fat (SCWBF). We aimed also to investigate the potential use of the anthropometric measures and fat distribution as predictors for the salivary adiponectin level in the healthy adult males. A total of 88 adult males aged between 18-25 years with a wide range of BMI were studied. Anthropometric indices were measured using standardized methods and salivary adiponectin level was assessed using an enzyme-linked immunosorbent assay. In path analysis of the Structural Equation Model (SEM) using IBM@SPSS AMOS, version22, BMI and WC, but not WHR, were strong predictors for WF and SCWBF (p<0.05). BMI but not WC was a strong predictor for VF (p<0.001). WF was strong predictor for SCWBF (p<0.001), but not for VF. BMI, WC, WHR, WF, VF, and SCWBF were poor predictors of the salivary adiponectin level. BMI is the best predictor for the total body fat and fat distribution. However, WHR seems to be of a little value and the salivary adiponectin level independent of BMI and body fat in healthy adult Malay males.

Family-based intervention in adolescent restrictive eating disorders: early treatment response and low weight suppression is associated with favourable one-year outcome

BackgroundFamily-based treatments are first-line treatments for adolescents with restrictive eating disorders (ED) but have to be improved since outcome is poor for some. We have investigated the one-year outcome of a family-based intervention programme with defined and decisive interventions at the start of treatment.MethodData pertaining 201 adolescents with restrictive ED with features of anorexia nervosa but not fulfilling the weight criterion starting treatment 2010-2015, had a wide range of body mass index (BMI) and of weight loss at presentation, and completed a one-year follow-up was analysed. Recovery from the ED was defined as an Eating Disorder Examination-questionnaire (EDE-Q) score < 2.0 or as not fulfilling criteria for an ED at a clinical interview.ResultsBy EDE-Q 130 (65%) had recovered at 1 year and by clinical interview 106 (53%). According to the EDE-Q criterion recovery was independently associated with lower EDE-Q score at presentation, higher weight gain after 3 months of treatment and lower weight suppression at follow-up, weight suppression being defined as the difference between premorbid and current BMI. Not fulfilling criteria for an ED was associated with the same factors and also by higher BMI at presentation.ConclusionThe observations that low weight and high ED cognitions confer a poor prognosis but that rapid weight gain at the start of treatment predicts a better prognosis are presently extended to adolescents with restrictive ED with a wide range of BMI at presentation. High weight suppression at follow-up is associated with a poor prognosis and indicates the importance of taking premorbid BMI into account when setting weight targets for treatment.

Impact Response Comparison Between Parametric Human Models and Postmortem Human Subjects with a Wide Range of Obesity Levels.

Field data analyses have shown that obesity significantly increases the occupant injury risks in motor vehicle crashes, but the injury assessment tools for people with obesity are largely lacking. The objectives of this study were to use a mesh morphing method to rapidly generate parametric finite element models with a wide range of obesity levels and to evaluate their biofidelity against impact tests using postmortem human subjects (PMHS). Frontal crash tests using three PMHS seated in a vehicle rear seat compartment with body mass index (BMI) from 24 to 40 kg/m2 were selected. To develop the human models matching the PMHS geometry, statistical models of external body shape, rib cage, pelvis, and femur were applied to predict the target geometry using age, sex, stature, and BMI. A mesh morphing method based on radial basis functions was used to rapidly morph a baseline human model into the target geometry. The model-predicted body excursions and injury measures were compared to the PMHS tests. Comparisons of occupant kinematics and injury measures between the tests and simulations showed reasonable correlations across the wide range of BMI levels. The parametric human models have the capability to account for the obesity effects on the occupant impact responses and injury risks.

Low AMY1 Gene Copy Number Is Associated with Increased Body Mass Index in Prepubertal Boys.

BackgroundGenome-wide association studies have identified more than 60 single nucleotide polymorphisms associated with Body Mass Index (BMI). Additional genetic variants, such as copy number variations (CNV), have also been investigated in relation to BMI. Recently, the highly polymorphic CNV in the salivary amylase (AMY1) gene, encoding an enzyme implicated in the first step of starch digestion, has been associated with obesity in adults and children. We assessed the potential association between AMY1 copy number and a wide range of BMI in a population of Italian school-children.Methods744 children (354 boys, 390 girls, mean age (±SD): 8.4±1.4years) underwent anthropometric assessments (height, weight) and collection of saliva samples for DNA extraction. AMY1 copies were evaluated by quantitative PCR.ResultsA significant increase of BMI z-score by decreasing AMY1 copy number was observed in boys (β: -0.117, p = 0.033), but not in girls. Similarly, waist circumference (β: -0.155, p = 0.003, adjusted for age) was negatively influenced by AMY1 copy number in boys. Boys with 8 or more AMY1 copy numbers presented a significant lower BMI z-score (p = 0.04) and waist circumference (p = 0.01) when compared to boys with less than 8 copy numbers.ConclusionsIn this pediatric-only, population-based study, a lower AMY1 copy number emerged to be associated with increased BMI in boys. These data confirm previous findings from adult studies and support a potential role of a higher copy number of the salivary AMY1 gene in protecting from excess weight gain.

Fast Automated Liver Delineation from Computational Tomography Angiography

Accurate liver segmentation is essential for surgery planning and diagnosis of liver abnormality with algorithms. We propose and validate a multi-atlas segmentation approach with local decision fusion for fast automated liver (with/without abnormality) segmentation on computational tomography angiography (CTA). Thirty-five patients were enrolled in this study. A co-registered segmented CTA atlas is constructed with 20 CTA scans, normal and abnormal subjects with wide range of body-mass index (BMI). Liver segmentation candidates are achieved by a multi-atlas registration algorithm which propagates the segmentation label on each atlas image to the test image by image registration. The final segmentation result is calculated by applying local decision fusion weights to each propagated candidate segmentation. We applied our algorithm on the rest 15 patients and compared them with manual segmentation by two expert readers. Voxel overlap by Dice coefficient between the algorithm and expert readers was 0.93 (range 0.89 - 0.94). The mean surface distance and Hausdorff distance in millimeters between manually drawn contoursand the automatically obtained contours were 1.1 ± 0.9mm and 5.9 ± 1.7mm respectively. Using our approach, physicians can accurately segment liver from CTA without tedious manual tracing. Our automated algorithm for liver segmentation achieved accurate segmentation with/without abnormality.

Relationship between etonogestrel level and BMI in women using the contraceptive implant for more than 1 year

Progestin-only contraceptive methods, including the 3-year, single-rod etonogestrel (ENG) implant, may be preferred for obese women to avoid additional estrogen-related thrombosis risk; however, whether obese women receive an ENG sufficient dose to suppress ovulation is understudied. Our analysis expands on the limited information currently available by studying ENG levels related to body mass index (BMI) in a community sample of primarily Hispanic women. This cross-sectional, descriptive study of 52 long-term implant users found comparable ENG levels across a wide BMI range (p=.1). These results further support that ENG levels are independent of BMI through 3 years of implant use and are thus reassuring that ENG implants will be effective for women of all BMIs.

Evaluation of Lean Body Weight Equation by Dual-Energy X-Ray Absorptiometry Measures.

When managing patients with disorders that require clinical intervention, a practical assessment of body habitus is valued. The Duffull-Green lean body weight (LBW) equation was derived and validated in adults across a wide body mass index (BMI) range. Whether this predictive equation will perform well in patients at BMI extremes or perform better than a widely used empiric "ideal" body weight (IBW) equation is unknown. Calculated LBW and calculated IBW were each compared with the dual-energy x-ray absorptiometry (DXA)-derived lean body mass (LBM) by simple linear regression. A mixed model was used to determine how well the LBW equation performed over time in patients with more than 1 DXA measurement. At time 0, 32 patients were 18-67 years old, and all were obese (BMI: 36-65 kg/m2), while the remaining 7 had parenteral nutrition-dependent intestinal failure (BMI: 17-25 kg/m2). A subset of patients underwent bariatric surgery after time 0 (BMI at follow-up: 22-49 kg/m2). The LBW equation was a predictor of LBM ( R2 = 0.67, P < .0001), while the IBW equation was not ( R2 = 0.04, P = .25). The LBW equation remained a predictor of LBM over time ( P < .0001) without significant interaction by number of months since time 0. The Duffull-Green LBW equation successfully predicted lean body mass in a patient population with a wide range of BMIs at both a single point in time and after considerable weight loss. In the clinical setting, an equation that performs well in various disease states and body sizes is advantageous.

Body Mass Index: Obesity, BMI, and Health: A Critical Review.

The body mass index (BMI) is the metric currently in use for defining anthropometric height/weight characteristics in adults and for classifying (categorizing) them into groups. The common interpretation is that it represents an index of an individual’s fatness. It also is widely used as a risk factor for the development of or the prevalence of several health issues. In addition, it is widely used in determining public health policies.The BMI has been useful in population-based studies by virtue of its wide acceptance in defining specific categories of body mass as a health issue. However, it is increasingly clear that BMI is a rather poor indicator of percent of body fat. Importantly, the BMI also does not capture information on the mass of fat in different body sites. The latter is related not only to untoward health issues but to social issues as well. Lastly, current evidence indicates there is a wide range of BMIs over which mortality risk is modest, and this is age related. All of these issues are discussed in this brief review.

Correlation Between Intraocular Pressure and Body Mass Index in the Seated and Supine Positions

Examine the relationship between intraocular pressure (IOP) and body mass index (BMI) in the seated and supine positions. A prospective observational study was conducted in which the IOP was measured with a Tono-Pen (Reichert Inc., Depew, NY) in seated and supine positions in eligible participants with a wide range of BMI (18 to 70 kg/m). The paired t test was used to compare seated to supine IOP. Stepwise regression analyses were used to investigate the correlation between IOP and BMI at these positions after adjusting for confounding variables of increased IOP, including age, race, mean arterial blood pressure, and central corneal thickness (μm). The mean sitting IOP (16.3±2.9 mm Hg) was statistically lower than the mean supine IOP (17.7±3.1 mm Hg; P<0.0001). For each 10 unit increase in BMI, there was an increase of 0.55±0.23 mm Hg (P=0.0184) in IOP in the seated position and an increase of 0.49±0.24 mm Hg in IOP in the supine position (P=0.0409). BMI did not have a significant effect on the amount of increase in IOP observed in changing from the seated to supine position. Higher BMI is correlated with higher IOP in both the seated and supine positions. However, BMI has no significant effect on the amount of increase in IOP observed in changing from the seated to supine position.

Accuracy of Reduced-Dose Computed Tomography for Ureteral Stones in Emergency Department Patients

Reduced-dose computed tomography (CT) scans have been recommended for diagnosis of kidney stone but are rarely used in the emergency department (ED) setting. Test characteristics are incompletely characterized, particularly in obese patients. Our primary outcome is to determine the sensitivity and specificity of a reduced-dose CT protocol for symptomatic ureteral stones, particularly those large enough to require intervention, using a protocol stratified by patient size. This was a prospective, blinded observational study of 201 patients at an academic medical center. Consenting subjects underwent both regular- and reduced-dose CT, stratified into a high and low body mass index (BMI) protocol based on effective abdominal diameter. Reduced-dose CT scans were interpreted by radiologists blinded to regular-dose interpretations. Follow-up for outcome and intervention was performed at 90 days. CT scans with both regular and reduced doses were conducted for 201 patients, with 63% receiving the high BMI reduced-dose protocol. Ureteral stone was identified in 102 patients (50.7%) of those receiving regular-dose CT, with a ureteral stone greater than 5 mm identified in 26 subjects (12.9%). Sensitivity of the reduced-dose CT for any ureteral stone was 90.2% (95% confidence interval [CI] 82.3% to 95.0%), with a specificity of 99.0% (95% CI 93.7% to 100.0%). For stones greater than 5 mm, sensitivity was 100% (95% CI 85.0% to 100.0%). Reduced-dose CT identified 96% of patients who required intervention for ureteral stone within 90 days. Mean reduction in size-specific dose estimate was 18.6 milligray (mGy), from 21.7 mGy (SD 9.7) to 3.4 mGy (SD 0.9). CT with substantial dose reduction was 90.2% (95% CI 82.3% to 95.0%) sensitive and 98.9% (95% CI 85.0% to 100.0%) specific for ureteral stones in ED patients with a wide range of BMIs. Reduced-dose CT was 96.0% (95% CI 80.5% to 99.3%) sensitive for ureteral stones requiring intervention within 90 days.

Body mass index and incident coronary heart disease in women: a population-based prospective study.

BackgroundA high body mass index (BMI) is associated with an increased risk of mortality from coronary heart disease (CHD); however, a low BMI may also be associated with an increased mortality risk. There is limited information on the relation of incident CHD risk across a wide range of BMI, particularly in women. We examined the relation between BMI and incident CHD overall and across different risk factors of the disease in the Million Women Study.Methods1.2 million women (mean age = 56 years) participants without heart disease, stroke, or cancer (except non-melanoma skin cancer) at baseline (1996 to 2001) were followed prospectively for 9 years on average. Adjusted relative risks and 20-year cumulative incidence from age 55 to 74 years were calculated for CHD using Cox regression.ResultsAfter excluding the first 4 years of follow-up, we found that 32,465 women had a first coronary event (hospitalization or death) during follow-up. The adjusted relative risk for incident CHD per 5 kg/m2 increase in BMI was 1.23 (95% confidence interval (CI) 1.22 to 1.25). The cumulative incidence of CHD from age 55 to 74 years increased progressively with BMI, from 1 in 11 (95% CI 1 in10 to 12) for BMI of 20 kg/m2, to 1 in 6(95% CI 1 in 5 to 7) for BMI of 34 kg/m2. A 10 kg/m2 increase in BMI conferred a similar risk to a 5-year increment in chronological age. The 20 year cumulative incidence increased with BMI in smokers and non-smokers, alcohol drinkers and non-drinkers, physically active and inactive, and in the upper and lower socioeconomic classes. In contrast to incident disease, the relation between BMI and CHD mortality (n = 2,431) was J-shaped. For the less than 20 kg/m2 and ≥35 kg/m2 BMI categories, the respective relative risks were 1.27 (95% CI 1.06 to 1.53) and 2.84 (95% CI 2.51 to 3.21) for CHD deaths, and 0.89 (95% CI 0.83 to 0.94) and 1.85 (95% CI 1.78 to 1.92) for incident CHD.ConclusionsCHD incidence in women increases progressively with BMI, an association consistently seen in different subgroups. The shape of the relation with BMI differs for incident and fatal disease.

Abstract P370: Obesity and Incident Coronary Heart Disease in the Million Women Study: A Prospective, Population-based Cohort Study

Background: Higher body-mass index (BMI) has been associated with increased risk for coronary heart disease (CHD) mortality but its association with incident CHD is less investigated, and data for women are limited. Methods: We examined the prospective relation between BMI and incident CHD (first CHD hospitalization or death) in 1.2 million women aged ≥50 years without prior CHD, who were recruited through a national breast screening programme in 1996 to 2001 and followed for an average of 9 years (48,842 events with 10.7 million person-years of follow-up). Absolute and relative risks (using Cox regression) associated with higher BMI were estimated. Results: After excluding the first 4 years of follow-up, there were 32,465 events (5.9 million person-years) including 3,345 CHD deaths. The adjusted relative risk per 5 kg/m 2 BMI difference was 1.24 [95% confidence interval (CI) 1.22 to 1.25]. CHD risk increased linearly across a wide range of BMI, with no apparent excess risk in the lower end of BMI distribution. The relation persisted after excluding current smokers or limiting cases to myocardial infarction only. For women in this cohort, the 20-year cumulative risk of CHD from age 55 to 74 years (95% CI) ranged from 9% (8 to10) to 18% (16 to 20) for women with BMI of 20 to 22.5 kg/m 2 and ≥35 kg/m 2 , respectively. Never smokers with BMI ≥35 kg/m 2 had comparable cumulative risk to current smokers with BMI of 20 to 22.5 kg/m 2 . Conclusion: In this large cohort of women, the impact of excess weight on CHD morbidity and mortality is substantial. Measures to prevent and control excess weight and other CHD risk factors are needed to help reduce CHD burden in women.

Expression of Clock Genes in Human Subcutaneous and Visceral Adipose Tissues

Disrupted circadian rhythms are associated with obesity and metabolic alterations, but little is known about the participation of peripheral circadian clock machinery in these processes. The aim of the present study was to analyze RNA expression of clock genes in subcutaneous (SAT) and visceral (VAT) adipose tissues of male and female subjects in AM (morning) and PM (afternoon) periods, and its interactions with body mass index (BMI). Ninety-one subjects (41 ± 11 yrs of age) presenting a wide range of BMI (21.4 to 48.6 kg/m2) were included. SAT and VAT biopsies were obtained from patients undergoing abdominal surgeries. Clock genes expressions were evaluated by qRT-PCR. The only clock gene that showed higher expression (p < .0001) in SAT in comparison to VAT was PER1 of female (372%) and male (326%) subjects. Different patterns of expression between the AM and PM periods were observed, in particular REV-ERBα, which was reduced (p < .05) at the PM period in SAT and VAT of both women and men (women: ∼53% lower; men: ∼78% lower), whereas CLOCK expression was not altered. Relationships between clock genes were different in SAT vs. VAT. BMI was negatively correlated with SATPER1 (r = −.549; p = .001) and SATPER2 (r = −.613; p = .0001) and positively with VATCLOCK (r = .541; p = .001) and VATBMAL1 (r = .468; p = .007) only in women. These data suggest that the circadian clock machinery of adipose tissue depots differs between female and male subjects, with a sex-specific effect observed for some genes. BMI correlated with clock genes, but at this moment it is not possible to establish the cause-effect relationship. (Author correspondence: mzanquetta@gmail.com)

Reduction of radiation exposure and improvement of image quality with BMI-adapted prospective cardiac computed tomography and iterative reconstruction

PurposeTo assess the impact of body mass index (BMI)-adapted protocols and iterative reconstruction algorithms (iDose) on patient radiation exposure and image quality in patients undergoing prospective ECG-triggered 256-slice coronary computed tomography angiography (CCTA). MethodsImage quality and radiation exposure were systematically analyzed in 100 patients. 60 Patients underwent prospective ECG-triggered CCTA using a non-tailored protocol and served as a ‘control’ group (Group 1: 120kV, 200mAs). 40 Consecutive patients with suspected coronary artery disease (CAD) underwent prospective CCTA, using BMI-adapted tube voltage and standard (Group 2: 100/120kV, 100–200mAs) versus reduced tube current (Group 3: 100/120kV, 75–150mAs). Iterative reconstructions were provided with different iDose levels and were compared to filtered back projection (FBP) reconstructions. Image quality was assessed in consensus of 2 experienced observers and using a 5-grade scale (1=best to 5=worse), and signal- and contrast-to-noise ratios (SNR and CNR) were quantified. ResultsCCTA was performed without adverse events in all patients (n=100, heart rate of 47–87bpm and BMI of 19–38kg/m2). Patients examined using the non-tailored protocol in Group 1 had the highest radiation exposure (3.2±0.4mSv), followed by Group 2 (1.7±0.7mSv) and Group 3 (1.2±0.6mSv) (radiation savings of 47% and 63%, respectively, p<0.001). Iterative reconstructions provided increased SNR and CNR, particularly when higher iDose level 5 was applied with Multi-Frequency reconstruction (iDose5 MFR) (14.1±4.6 versus 21.2±7.3 for SNR and 12.0±4.2 versus 18.1±6.6 for CNR, for FBP versus iDose5 MFR, respectively, p<0.001). The combination of BMI adaptation with iterative reconstruction reduced radiation exposure and simultaneously improved image quality (subjective image quality of 1.4±0.4 versus 1.9±0.5 for Group 2 reconstructed using iDose5 MFR versus Group 1 reconstructed using FBP, p<0.05). ConclusionsProspective ECG-triggered 256-slice CCTA allows for visualization of the coronary artery tree with high image quality within a wide range of heart rates and BMIs. The combination of BMI-adapted protocols with iterative reconstruction algorithms can reduce radiation exposure for the patients and simultaneously improve image quality.

Clinical and Radiographic Predictors of GOLD–Unclassified Smokers in the COPDGene Study

A significant proportion of smokers have lung function impairment characterized by a reduced FEV(1) with a preserved FEV(1)/FVC ratio. These smokers are a poorly characterized group due to their systematic exclusion from chronic obstructive pulmonary disease (COPD) studies. To characterize the clinical, functional, and radiographic features of Global Initiative for Chronic Obstructive Lung Disease (GOLD)-Unclassified (FEV(1)/FVC ≥ 0.7 and FEV(1) < 80% predicted) and lower limits of normal (LLN)-unclassified (FEV(1)/FVC ≥ LLN and FEV(1) < LLN) subjects compared to smokers with normal lung function and subjects with COPD. Data from the first 2,500 subjects enrolled in the COPDGene study were analyzed. All subjects had 10 or more pack-years of smoking and were between the ages of 45 and 80 years. Multivariate regression models were constructed to determine the clinical and radiological variables associated with GOLD-Unclassified (GOLD-U) and LLN-Unclassified status. Separate multivariate regressions were performed in the subgroups of subjects with complete radiologic measurement variables available. GOLD-U smokers account for 9% of smokers in COPDGene and have increased body mass index (BMI), a disproportionately reduced total lung capacity, and a higher proportion of nonwhite subjects and subjects with diabetes. GOLD-U subjects exhibit increased airway wall thickness compared to smoking control subjects and decreased gas trapping and bronchodilator responsiveness compared to subjects with COPD. When LLN criteria were used to define the "unclassified" group, African American subjects were no longer overrepresented. Both GOLD-U and LLN-Unclassified subjects demonstrated a wide range of lung function impairment, BMI, and percentage of total lung emphysema. Subjects with reduced FEV(1) and a preserved FEV(1)/FVC ratio are a heterogeneous group with significant symptoms and functional limitation who likely have a variety of underlying etiologies beyond increased BMI. Clinical trial registered with www.clinicaltrials.gov (NCT000608764).