A composite score combining waist circumference and body mass index more accurately predicts body fat percentage in 6- to 13-year-old children

Purpose: Body mass index (BMI) and waist circumference (WC) are widely used to predict % body fat (BF) and classify degrees of pediatric adiposity. However, both measures have limitations. The aim of this study was to evaluate whether a combination of WC and BMI would more accurately predict %BF than either alone. Methods: In a nationally representative sample of 2,303 6- to 13-year-old Swiss children, weight, height, and WC were measured, and %BF was determined from multiple skinfold thicknesses. Regression and receiver operating characteristic (ROC) curves were used to evaluate the combination of WC and BMI in predicting %BF against WC or BMI alone. An optimized composite score (CS) was generated. Results: A quadratic polynomial combination of WC and BMI led to a better prediction of %BF (r 2=0.68) compared with the two measures alone (r 2=0.58-0.62). The areas under the ROC curve for the CS [0.6*WC-SDS+0.4*BMI-SDS] ranged from 0.962±0.0053 (overweight girls) to 0.982±0.0046 (obese boys) and were somewhat greater than the AUCs for either BMI or WC alone. At a given specificity, the sensitivity of the prediction of overweight and obesity based on the CS was higher than that based on either WC or BMI alone, although the improvement was small. Conclusion: Both BMI and WC are good predictors of %BF in primary school children. However, a composite score incorporating both measures increased sensitivity at a constant specificity as compared to the individual measures. It may therefore be a useful tool for clinical and epidemiological studies of pediatric adiposit

Euclid preparation : IX. EuclidEmulator2 – power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

We present a new, updated version of the EuclidEmulator (called EuclidEmulator2), a fast and accurate predictor for the nonlinear correction of the matter power spectrum. 2 per cent level accurate emulation is now supported in the eight-dimensional parameter space of w(0)w(a)CDM+Sigma m(nu) models between redshift z = 0 and z = 3 for spatial scales within the range . In order to achieve this level of accuracy, we have had to improve the quality of the underlying N-body simulations used as training data: (i) we use self-consistent linear evolution of non-dark matter species such as massive neutrinos, photons, dark energy, and the metric field, (ii) we perform the simulations in the so-called N-body gauge, which allows one to interpret the results in the framework of general relativity, (iii) we run over 250 high-resolution simulations with 3000(3) particles in boxes of 1(h(-1)Gpc)(3) volumes based on paired-and-fixed initial conditions, and (iv) we provide a resolution correction that can be applied to emulated results as a post-processing step in order to drastically reduce systematic biases on small scales due to residual resolution effects in the simulations. We find that the inclusion of the dynamical dark energy parameter w(a) significantly increases the complexity and expense of creating the emulator. The high fidelity of EuclidEmulator2 is tested in various comparisons against N-body simulations as well as alternative fast predictors such as HALOFIT, HMCode, and CosmicEmu. A blind test is successfully performed against the Euclid Flagship v2.0 simulation. Nonlinear correction factors emulated with EuclidEmulator2 are accurate at the level of or better for and zPeer reviewe

(13)N-ammonia myocardial perfusion imaging with a PET/CT scanner: impact on clinical decision making and cost-effectiveness

PURPOSE: The purpose of the study is to determine the impact of 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI) on clinical decision making and its cost-effectiveness. MATERIALS AND METHODS: One hundred consecutive patients (28 women, 72 men; mean age 60.9 +/- 12.0 years; range 24-85 years) underwent 13N-ammonia PET scanning (and computed tomography, used only for attenuation correction) to assess myocardial perfusion in patients with known (n = 79) or suspected (n = 8) coronary artery disease (CAD), or for suspected small-vessel disease (SVD; n = 13). Before PET, the referring physician was asked to determine patient treatment if PET would not be available. Four weeks later, PET patient management was reassessed for each patient individually. RESULTS: Before PET management strategies would have been: diagnostic angiography (62 of 100 patients), diagnostic angiography and percutaneous coronary intervention (PCI; 6 of 100), coronary artery bypass grafting (CABG; 3 of 100), transplantation (1 of 100), or conservative medical treatment (28 of 100). After PET scanning, treatment strategies were altered in 78 patients leading to: diagnostic angiography (0 of 100), PCI (20 of 100), CABG (3 of 100), transplantation (1 of 100), or conservative medical treatment (76 of 100). Patient management followed the recommendations of PET findings in 97% of the cases. Cost-effectiveness analysis revealed lower costs of 206/patient as a result of PET scanning. CONCLUSION: In a population with a high prevalence of known CAD, PET is cost-effective and has an important impact on patient management

13N-ammonia myocardial perfusion imaging with hybrid PET/CT: impact on clinical decision-making and cost-effectiveness

To determine the impact of 13N-ammonia myocardial perfusion positron emission tomography-computed tomography (PET/CT) hybrid imaging on clinical decision-making and its cost-effectiveness. Methods: One hundred consecutive patients (28 women, 72 men; mean age 60.9�12.0 years; range 24-85 years) underwent 13N-ammonia PET/CT (CT was only used for attenuation correction) scanning to assess myocardial perfusion in patients with known (n=79) or suspected (n=8) coronary artery disease (CAD), or for suspected small vessel disease (SVD)(n=13). Prior to PET/CT the referring physician was asked to determine patient treatment if PET/CT would not be available. Four weeks after PET/CT patient management was re-assessed for each patient individually. Results: Prior to PET/CT management strategies would have been: diagnostic angiography (62/100 patients), percutaneous coronary intervention (PCI) (6/100), coronary artery bypass grafting (CABG) (3/100), transplantation (1/100), or conservative medical treatment (28/100). After PET/CT scanning treatment strategies were altered in 78 patients leading to: diagnostic angiography (0/100), PCI (20/100), CABG (3/100), transplantation (1/100), or conservative medical treatment (76/100). Patient management followed the recommendations of PET/CT findings in 97% of the cases. Cost-effectiveness analysis revealed lower costs of $273/patient as a result of PET/CT scanning. Conclusion: In a population with a high prevalence of CAD, PET/CT is cost-effective and has an important impact on patient management

Decrease in the prevalence of paediatric adiposity in Switzerland from 2002 to 2007

OBJECTIVE: A national study in Switzerland in 2002 suggested nearly one in five schoolchildren was overweight. Since then, many programmes have been introduced in an attempt to control the problem. The aim of the present study was to determine the prevalence of childhood overweight in Switzerland five years later. DESIGN: In both studies a cross-sectional, three-stage, probability-proportional-to-size cluster sampling of schools throughout Switzerland was used to obtain a representative sample of approximately 2500 children aged 6-13 years. Height and weight were measured and BMI calculated. The BMI references from the Centers for Disease Control and Prevention were used to determine the prevalences of underweight (/=85th and /=95th percentile). RESULTS: In 2007 the prevalences of underweight, overweight and obesity in boys were 3.5 %, 11.3 % and 5.4 %, respectively; in girls they were 2.6 %, 9.9 % and 3.2 %. Compared with 2002, there was a significant decrease in the prevalence of overweight in girls and of obesity in both genders. In contrast to 2002, where there were no differences, in 2007 the prevalence of paediatric obesity was significantly higher in communities with a population >100 000 compared with smaller communities (P < 0.05). CONCLUSIONS: In summary, over the past 5 years, the prevalence of adiposity has decreased in Swiss children. These findings suggest that increased awareness combined with mainly school-based programmes aimed at physical activity and healthy nutrition may have helped to control this public health problem. Future monitoring in Switzerland will determine if these findings are sustained

Waist circumference and waist-to-height ratio percentiles in a nationally representative sample of 6-13 year old children in Switzerland

OBJECTIVES: Central obesity, measured as waist circumference (WC), is an important risk factor for cardiovascular disease and diabetes already in children. The ratio of waist circumference to height (WHtR) is a further indicator for body shape. International reference values, however, do not exist for any of the two measures and neither do references specific to Switzerland. The aim of this study therefore was to develop WC and WHtR percentiles from a nationally representative sample of Swiss children. METHODS: In a nationally representative sample of 2,303 6 to 13 year old children in Switzerland weight, height and WC were measured and body fat % (%BF) was determined from multiple skinfold-thickness measurements. WC, WHtR and % BF percentiles were calculated using the LMS-Method of Cole and Green. RESULTS: WC increases almost linearly over the age range of 6 to 13 years for both boys and girls. Generally, girls show slightly lower WC than boys, but in the higher percentiles (85th, 90th and 95th) they reach the same or even slightly higher values around 10 years of age. At the 85th percentile for boys and the 90th percentile for girls, WHtR remains constant over the entire age range. Above these levels the ratio increases and below it decreases with age. Percentiles for %BF in boys increase constantly up to an age of 11.5 years, after which they plateau. For girls, the plateau can be seen earlier, around 10.5 years, but at 12.5 years another increase begins. CONCLUSION: These first WC and WHtR percentiles may be useful for clinical and epidemiological use in Switzerland until official, validated references become available. An advantage in using WHtR seems to be that it is not age dependent at certain levels and it may therefore be possible to use a single cut-off value for all children

Euclid preparation: IX. EuclidEmulator2 – power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

We present a new, updated version of the EuclidEmulator (called EuclidEmulator2), a fast and accurate predictor for the nonlinear correction of the matter power spectrum. 2 per cent level accurate emulation is now supported in the eight-dimensional parameter space of w0waCDM+∑mν models between redshift z = 0 and z = 3 for spatial scales within the range 0.01hMpc−1≤k≤10hMpc−1⁠. In order to achieve this level of accuracy, we have had to improve the quality of the underlying N-body simulations used as training data: (i) we use self-consistent linear evolution of non-dark matter species such as massive neutrinos, photons, dark energy, and the metric field, (ii) we perform the simulations in the so-called N-body gauge, which allows one to interpret the results in the framework of general relativity, (iii) we run over 250 high-resolution simulations with 30003 particles in boxes of 1(h−1 Gpc)3 volumes based on paired-and-fixed initial conditions, and (iv) we provide a resolution correction that can be applied to emulated results as a post-processing step in order to drastically reduce systematic biases on small scales due to residual resolution effects in the simulations. We find that the inclusion of the dynamical dark energy parameter wa significantly increases the complexity and expense of creating the emulator. The high fidelity of EuclidEmulator2 is tested in various comparisons against N-body simulations as well as alternative fast predictors such as HALOFIT, HMCode, and CosmicEmu. A blind test is successfully performed against the Euclid Flagship v2.0 simulation. Nonlinear correction factors emulated with EuclidEmulator2 are accurate at the level of 1 per cent or better for 0.01hMpc−1≤k≤10hMpc−1 and z ≤ 3 compared to high-resolution dark-matter-only simulations. EuclidEmulator2 is publicly available at https://github.com/miknab/EuclidEmulator2

A composite score combining waist circumference and body mass index more accurately predicts body fat percentage in 6-to 13-year-old children

Body mass index (BMI) and waist circumference (WC) are widely used to predict % body fat (BF) and classify degrees of pediatric adiposity. However, both measures have limitations. The aim of this study was to evaluate whether a combination of WC and BMI would more accurately predict %BF than either alone. In a nationally representative sample of 2,303 6- to 13-year-old Swiss children, weight, height, and WC were measured, and %BF was determined from multiple skinfold thicknesses. Regression and receiver operating characteristic (ROC) curves were used to evaluate the combination of WC and BMI in predicting %BF against WC or BMI alone. An optimized composite score (CS) was generated. A quadratic polynomial combination of WC and BMI led to a better prediction of %BF (r (2) = 0.68) compared with the two measures alone (r (2) = 0.58-0.62). The areas under the ROC curve for the CS [0.6 * WC-SDS + 0.4 * BMI-SDS] ranged from 0.962 +/- A 0.0053 (overweight girls) to 0.982 +/- A 0.0046 (obese boys) and were somewhat greater than the AUCs for either BMI or WC alone. At a given specificity, the sensitivity of the prediction of overweight and obesity based on the CS was higher than that based on either WC or BMI alone, although the improvement was small. Both BMI and WC are good predictors of %BF in primary school children. However, a composite score incorporating both measures increased sensitivity at a constant specificity as compared to the individual measures. It may therefore be a useful tool for clinical and epidemiological studies of pediatric adiposity

c-Myc controls the balance between hematopoietic stem cell self-renewal and differentiation

The activity of adult stem cells is essential to replenish mature cells constantly lost due to normal tissue turnover. By a poorly understood mechanism, stem cells are maintained through self-renewal while concomitantly producing differentiated progeny. Here, we provide genetic evidence for an unexpected function of the c-Myc protein in the homeostasis of hematopoietic stem cells (HSCs). Conditional elimination of c-Myc activity in the bone marrow (BM) results in severe cytopenia and accumulation of HSCs in situ. Mutant HSCs self-renew and accumulate due to their failure to initiate normal stem cell differentiation. Impaired differentiation of c-Myc-deficient HSCs is linked to their localization in the differentiation preventative BM niche environment, and correlates with up-regulation of N-cadherin and a number of adhesion receptors, suggesting that release of HSCs from the stem cell niche requires c-Myc activity. Accordingly, enforced c-Myc expression in HSCs represses N-cadherin and integrins leading to loss of self-renewal activity at the expense of differentiation. Endogenous c-Myc is differentially expressed and induced upon differentiation of long-term HSCs. Collectively, our data indicate that c-Myc controls the balance between stem cell self-renewal and differentiation, presumably by regulating the interaction between HSCs and their niche