331 research outputs found
Growth references for height, weight and body mass index of twins aged 0–2.5 years.
Aim: To determine the size of the growth deficit in Dutch monozygotic and dizygotic twins aged 0-2.5 years as compared to singletons and to construct reference growth charts for twins. Methods: Growth of twins was studied using longitudinal data on over 4000 twins aged 0-2.5 years of the Netherlands Twin Register. The LMS method was used to obtain growth references for length/height, weight, and body mass index (BMI) for twins. Results: During the first 2.5 years of age, differences in length/height and weight between twins and singletons decrease but do not disappear. BMI of twins deviates less than that of singletons. Approximately half of the growth retardation from birth until 1.5 years of age was attributable to gestational age. Between 1.5 years and 2.5 years of age, this difference was reduced to one-third. Thus, a substantial part of the growth difference could not be explained by gestational age. © 2008 Foundation Acta Pædiatrica
Fibroblast Growth Factor 23, Glucose Homeostasis, and Incident Diabetes:Findings of 2 Cohort Studies
CONTEXT: The phosphate-regulating hormone fibroblast growth factor 23 (FGF23) has been linked to deregulations in glucose metabolism, but its role is insufficiently understood.OBJECTIVE: This study investigates potential crosstalk between FGF23 and glucose homeostasis.METHODS: First, we investigated the effect of glucose loading on plasma C-terminal FGF23 levels and its temporal relationship with changes in plasma phosphate in 45 overweight (body mass index [BMI] 25-30) individuals using time-lag analyses. Second, we studied cross-sectional associations of plasma C-terminal FGF23 levels with glucose homeostasis using multivariable linear regression in a population-based cohort. We also investigated associations of FGF23 with incident diabetes and obesity (BMI > 30) in individuals without diabetes or obesity at baseline, respectively, using multivariable Cox regression analyses. Finally, we explored whether the association between FGF23 and diabetes depends on BMI.RESULTS: After glucose loading, changes in FGF23 preceded changes in plasma phosphate (Ptime-lag = .04). In the population-based cohort (N = 5482; mean age 52 years, 52% women, median FGF23 69 RU/mL), FGF23 was associated with plasma glucose (β = .13 [.03-.23]; P = .01), insulin (β = .10 [.03-.17]; P < .001), and proinsulin (β = .06 [0.02-0.10]; P = .01) at baseline. On longitudinal analyses, a higher baseline FGF23 was independently associated with development of diabetes (199 events [4%]; fully adjusted hazard ratio [HR] 1.66 [95% CI, 1.06-2.60]; P = .03) and development of obesity (241 events [6%]; fully adjusted HR 1.84 [95% CI, 1.34-2.50]; P < .001). The association between FGF23 and incident diabetes lost significance after additional adjustment for BMI.CONCLUSION: Glucose loading has phosphate-independent effects on FGF23 and, vice versa, FGF23 is associated with glucose, insulin and proinsulin levels, and obesity. These findings suggest crosstalk between FGF23 and glucose homeostasis, which may promote susceptibility to incident diabetes.</p
Plasma phosphate and all-cause mortality in individuals with and without type 2 diabetes:the Dutch population-based lifelines cohort study
INTRODUCTION: Individuals with type 2 diabetes have a substantially elevated cardiovascular risk. A higher plasma phosphate level promotes vascular calcification, which may adversely affect outcomes in individuals with type 2 diabetes. We hypothesized that the association between plasma phosphate and all-cause mortality is stronger in individuals with type 2 diabetes, compared to those without diabetes. METHODS: We analysed the association between plasma phosphate and all-cause mortality in the Dutch population-based Lifelines cohort and in subgroups with and without type 2 diabetes, using multivariable Cox regression adjusted for potential confounders. Effect modification was tested using multiplicative interaction terms. RESULTS: We included 57,170 individuals with 9.4 [8.8-10.4] years follow-up. Individuals within the highest phosphate tertile (range 1.00-1.83 mmol/L) were at higher risk of all-cause mortality (fully adjusted HR 1.18 [95% CI 1.02-1.36], p = 0.02), compared with the intermediate tertile (range 0.85-0.99 mmol/L). We found significant effect modification by baseline type 2 diabetes status (p-interaction = 0.003). Within the type 2 diabetes subgroup (N = 1790), individuals within the highest plasma phosphate tertile had an increased mortality risk (HR 1.73 [95% CI 1.10-2.72], p = 0.02 vs intermediate tertile). In individuals without diabetes at baseline (N = 55,380), phosphate was not associated with mortality (HR 1.12 [95% CI 0.96-1.31], p = 0.14). Results were similar after excluding individuals with eGFR < 60 mL/min/1.73 m2. DISCUSSION: High-normal plasma phosphate levels were associated with all-cause mortality in individuals with type 2 diabetes. The association was weaker and non-significant in those without diabetes. Measurement of phosphate levels should be considered in type 2 diabetes; whether lowering phosphate levels can improve health outcomes in diabetes requires further study
Tomography and state reconstruction with superconducting single-photon detectors
We perform quantum state reconstruction of coherent and thermal states with a
detector which has an enhanced multiphoton response. The detector is based on
superconducting nanowires, where the bias current sets the dependence of the
click probability on the photon number; this bias current is used as tuning
parameter in the state reconstruction. The nonlinear response makes our
nanowire-based detector superior to the linear detectors that are
conventionally used for quantum state reconstruction.Comment: revision of intro compared to V
Prognostic factors of local control and disease free survival in centrally located non-small cell lung cancer treated with stereotactic body radiation therapy
Background: Stereotactic body radiation therapy (SBRT) results in high local control (LC) rates in
patients with non-small cell lung cancer (NSCLC). For central lung tumors, risk-adapted fractionation
schedules are used and underdosage to the Planned Target Volume (PTV) is often accepted to respect
the dose constraints of the organs at risk in order to avoid high rates of toxicity. The purpose of this
study was to analyze the effect of PTV underdosage and other possible prognostic factors on localand disease control after SBRT in patients with central lung tumors.
Material and Methods: Patients with centrally located NSCLC treated with SBRT were included. The
doses were converted into biologically equivalent dose using a/b-value of 10 Gy (BED10). Underdosage
to the PTV was defined as the (percentage of) PTV receiving less than 100 Gy BED10; (%)PTV < 100
BED10. Potential prognostic factors for LC and Disease Free Survival (DFS) were evaluated using Cox
regression analysis.
Results: Two hundred and twenty patients received 12 fractions of SBRT. LC-rates were 88% at
2 years and 81% at 3 years. Twenty-seven patients developed a local recurrence. Both the PTV < 100
BED10 and %PTV < 100 BED10 were not prognostic for LC. Tumor size and forced expiratory volume in
1 second (FEV1) were independently prognostic for LC. Disease progression was reported in 75 patients
with DFS-rates of 66% at 2 years and 56% at 3 years. Disea
Tensor Regression with Applications in Neuroimaging Data Analysis
Classical regression methods treat covariates as a vector and estimate a
corresponding vector of regression coefficients. Modern applications in medical
imaging generate covariates of more complex form such as multidimensional
arrays (tensors). Traditional statistical and computational methods are proving
insufficient for analysis of these high-throughput data due to their ultrahigh
dimensionality as well as complex structure. In this article, we propose a new
family of tensor regression models that efficiently exploit the special
structure of tensor covariates. Under this framework, ultrahigh dimensionality
is reduced to a manageable level, resulting in efficient estimation and
prediction. A fast and highly scalable estimation algorithm is proposed for
maximum likelihood estimation and its associated asymptotic properties are
studied. Effectiveness of the new methods is demonstrated on both synthetic and
real MRI imaging data.Comment: 27 pages, 4 figure
Protocol for the CUPIDO trials; multicenter randomized controlled trials to assess the value of combining prolapse surgery and incontinence surgery in patients with genital prolapse and evident stress incontinence (CUPIDO I) and in patients with genital prolapse and occult stress incontinence (CUPIDO II)
Background: About 40% of all patients with genital prolapse report stress-incontinence. In about half of the 60% patients that do not report stress-incontinence, occult urinary stress-incontinence can be detected. In these patients stress-incontinence is masked due to kinking or compression of the urethra by the prolapse. In case surgical correction is indicated there are two strategies to manage patients with combined prolapse and (occult) stress incontinence. This strategy is either (i) a combination of prolapse surgery and stress-incontinence surgery or (ii) to correct the prolapse first and evaluate afterwards whether additional stress-incontinence surgery is indicated. The advantage of combining prolapse and stress-incontinence surgery is that only few patients report stress-incontinence following such combination. However, this combination has been associated with an increased risk on complications, of which the development of obstructive micturition symptoms, overactive bladder symptoms and bladder retention are the most important ones. Furthermore, combining two procedures may be unnecessary as performing only prolapse surgery may cure stress-incontinence In the randomized CUPIDO trials both strategies are compared in patients with prolapse and evident stress incontinence (CUPIDO I trial) and in patients with prolapse and occult stress incontinence (CUPIDO II trial). Methods/Design: The CUPIDO trials are two multicenter randomized controlled trials in which women with stress urinary incontinence (SUI) or occult stress urinary incontinence (OSUI) are randomized to prolapse surgery combined with anti incontinence surgery (concomitant surgery) or to prolapse surgery only. Patients with at least stage 2 POP are eligible, women with evident SUI are randomized in CUPIDO I. Patients without SUI are eligible for CUPIDO II and will have urodynamic evaluation or a standardized redression test. Women with OSUI are randomized, women without OSUI are followed up but not randomized. The primary outcome measure is absence of SUI twelve months after surgery. Furthermore, economic evaluations are conducted, and the effectiveness of urodynamic investigation is evaluated against a non-invasive way to determine SUI in women with POP. A total of 450 women will be included in the study
Detecting the direction of a signal on high-dimensional spheres: Non-null and Le Cam optimality results
We consider one of the most important problems in directional statistics,
namely the problem of testing the null hypothesis that the spike direction
of a Fisher-von Mises-Langevin distribution on the -dimensional
unit hypersphere is equal to a given direction . After a reduction
through invariance arguments, we derive local asymptotic normality (LAN)
results in a general high-dimensional framework where the dimension goes
to infinity at an arbitrary rate with the sample size , and where the
concentration behaves in a completely free way with , which
offers a spectrum of problems ranging from arbitrarily easy to arbitrarily
challenging ones. We identify various asymptotic regimes, depending on the
convergence/divergence properties of , that yield different
contiguity rates and different limiting experiments. In each regime, we derive
Le Cam optimal tests under specified and we compute, from the Le Cam
third lemma, asymptotic powers of the classical Watson test under contiguous
alternatives. We further establish LAN results with respect to both spike
direction and concentration, which allows us to discuss optimality also under
unspecified . To investigate the non-null behavior of the Watson test
outside the parametric framework above, we derive its local asymptotic powers
through martingale CLTs in the broader, semiparametric, model of rotationally
symmetric distributions. A Monte Carlo study shows that the finite-sample
behaviors of the various tests remarkably agree with our asymptotic results.Comment: 47 pages, 4 figure
Trade-offs in Large-Scale Distributed Tuplewise Estimation and Learning
The development of cluster computing frameworks has allowed practitioners to
scale out various statistical estimation and machine learning algorithms with
minimal programming effort. This is especially true for machine learning
problems whose objective function is nicely separable across individual data
points, such as classification and regression. In contrast, statistical
learning tasks involving pairs (or more generally tuples) of data points - such
as metric learning, clustering or ranking do not lend themselves as easily to
data-parallelism and in-memory computing. In this paper, we investigate how to
balance between statistical performance and computational efficiency in such
distributed tuplewise statistical problems. We first propose a simple strategy
based on occasionally repartitioning data across workers between parallel
computation stages, where the number of repartitioning steps rules the
trade-off between accuracy and runtime. We then present some theoretical
results highlighting the benefits brought by the proposed method in terms of
variance reduction, and extend our results to design distributed stochastic
gradient descent algorithms for tuplewise empirical risk minimization. Our
results are supported by numerical experiments in pairwise statistical
estimation and learning on synthetic and real-world datasets.Comment: 23 pages, 6 figures, ECML 201
Two Randomized Controlled Trials of Bacillus Calmette-Guerin Vaccination to reduce absenteeism among health care workers and hospital admission by elderly persons during the COVID-19 pandemic: A structured summary of the study protocols for two randomised controlled trials (vol 21, 481, 2020)
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