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Composite quantile regression

David Bann, William Johnson, Leah Li, Diana Kuh, Rebecca Hardy
BACKGROUND: Socioeconomic inequalities in childhood body-mass index (BMI) have been documented in high-income countries; however, uncertainty exists with regard to how they have changed over time, how inequalities in the composite parts (ie, weight and height) of BMI have changed, and whether inequalities differ in magnitude across the outcome distribution. Therefore, we aimed to investigate how socioeconomic inequalities in childhood and adolescent weight, height, and BMI have changed over time in Britain...
March 20, 2018: Lancet. Public Health
Xiaofang Jia, Jiawu Liu, Bo Chen, Donghui Jin, Zhongxi Fu, Huilin Liu, Shufa Du, Barry M Popkin, Michelle A Mendez
OBJECTIVE: Eating away from home is associated with poor diet quality, in part due to less healthy food choices and larger portions. However, few studies account for the potential additional contribution of differences in food composition between restaurant- and home-prepared dishes. The present study aimed to investigate differences in nutrients of dishes prepared in restaurants v. at home. DESIGN: Eight commonly consumed dishes were collected in twenty of each of the following types of locations: small and large restaurants, and urban and rural households...
January 8, 2018: Public Health Nutrition
Caterina Trozzi, Francesca Raffaelli, Arianna Vignini, Laura Nanetti, Rosaria Gesuita, Laura Mazzanti
PURPOSE: Recently, there was an increasing interest on the use of ancient grains because of their better health-related composition. The aim of this study was to evaluate in healthy human subjects the antioxidative and diabetes-preventive properties of ancient KAMUT ® khorasan wheat compared to modern wheat. METHODS: The study was a randomized, non-blind, parallel arm study where the biochemical parameters of volunteers with a diet based on organic whole grain KAMUT ® khorasan products, as the only source of cereal products were compared to a similar replacement diet based on organic whole grain modern durum wheat products...
November 16, 2017: European Journal of Nutrition
Darren L Dahly, Xia Li, Hazel A Smith, Ali S Khashan, Deirdre M Murray, Mairead E Kiely, Jonathan O'B Hourihane, Fergus P McCarthy, Louise C Kenny, Patricia M Kearney
Background: Neonatal body composition likely mediates fetal influences on life long chronic disease risk. A better understanding of how maternal lifestyle is related to newborn body composition could thus inform intervention efforts. Methods: Using Cork participant data (n = 1754) from the Screening for Pregnancy Endpoints (SCOPE) cohort study [ECM5(10)05/02/08], we estimated how pre-pregnancy body size, gestational weight gain, exercise, alcohol, smoking and diet were related to neonatal fat and fat-free mass, as well as length and gestational age at birth, using quantile regression...
February 1, 2018: International Journal of Epidemiology
Maliheh Arekhi, Osman Yalçın Yılmaz, Hatice Yılmaz, Yaşar Feyza Akyüz
The diversity of forest trees as an indicator of ecosystem health can be assessed using the spectral characteristics of plant communities through remote sensing data. The objectives of this study were to investigate alpha and beta tree diversity using Landsat data for six dates in the Gönen dam watershed of Turkey. We used richness and the Shannon and Simpson diversity indices to calculate tree alpha diversity. We also represented the relationship between beta diversity and remotely sensed data using species composition similarity and spectral distance similarity of sampling plots via quantile regression...
October 28, 2017: Environmental Monitoring and Assessment
Erik Nilsson, Yang Cao, Bengt Lindholm, Ayane Ohyama, Juan Jesus Carrero, Abdul Rashid Qureshi, Peter Stenvinkel
Background: High pregnancy-associated plasma protein-A (PAPP-A) levels are linked to atherosclerosis and associate with increased mortality in prevalent dialysis patients. We investigated associations of PAPP-A, measured at dialysis initiation, with cardiovascular disease (CVD), CVD risk factors and mortality in incident dialysis patients, and explored if body composition and inflammation modulated these associations. Methods: Baseline plasma PAPP-A levels, inflammation biomarkers and body composition, using dual-energy X-ray absorptiometry, were measured in 286 incident dialysis patients...
July 24, 2017: Nephrology, Dialysis, Transplantation
Monique Anderson Starks, Robert H Schmicker, Eric D Peterson, Susanne May, Jason E Buick, Peter J Kudenchuk, Ian R Drennan, Heather Herren, Jamie Jasti, Michael Sayre, Dion Stub, Gary M Vilke, Shannon W Stephens, Anna M Chang, Jack Nuttall, Graham Nichol
Importance: We examined whether resuscitation care and outcomes vary by the racial composition of the neighborhood where out-of-hospital cardiac arrests (OHCAs) occur. Objective: To evaluate the association between bystander treatments (cardiopulmonary resuscitation and automatic external defibrillation) and timing of emergency medical services personnel on OHCA outcomes according to the racial composition of the neighborhood where the OHCA event occurred. Design, Setting, and Participants: This retrospective observational cohort study examined patients with OHCA from January 1, 2008, to December 31, 2011, using data from the Resuscitation Outcomes Consortium...
October 1, 2017: JAMA Cardiology
Lisa H Nowell, Patrick W Moran, Travis S Schmidt, Julia E Norman, Naomi Nakagaki, Megan E Shoda, Barbara J Mahler, Peter C Van Metre, Wesley W Stone, Mark W Sandstrom, Michelle L Hladik
Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May-August 2013. In weekly water samples, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per sample and 54 detected per site...
February 1, 2018: Science of the Total Environment
David C Wheeler, Jenna Czarnota, Resa M Jones
Socioeconomic status (SES) is often considered a risk factor for health outcomes. SES is typically measured using individual variables of educational attainment, income, housing, and employment variables or a composite of these variables. Approaches to building the composite variable include using equal weights for each variable or estimating the weights with principal components analysis or factor analysis. However, these methods do not consider the relationship between the outcome and the SES variables when constructing the index...
2017: PloS One
Chi-Chuan Yang, Yi-Hau Chen, Hsing-Yi Chang
Childhood and adolescenthood overweight or obesity, which may be quantified through the body mass index (BMI), is strongly associated with adult obesity and other health problems. Motivated by the child and adolescent behaviors in long-term evolution (CABLE) study, we are interested in individual, family, and school factors associated with marginal quantiles of longitudinal adolescent BMI values. We propose a new method for composite marginal quantile regression analysis for longitudinal outcome data, which performs marginal quantile regressions at multiple quantile levels simultaneously...
June 2, 2017: Statistics in Medicine
Patrick W Moran, Lisa H Nowell, Nile E Kemble, Barbara J Mahler, Ian R Waite, Peter C Van Metre
Simultaneous assessment of sediment chemistry, sediment toxicity, and macroinvertebrate communities can provide multiple lines of evidence when investigating relations between sediment contaminants and ecological degradation. These three measures were evaluated at 99 wadable stream sites across 11 states in the Midwestern United States during the summer of 2013 to assess sediment pollution across a large agricultural landscape. This evaluation considers an extensive suite of sediment chemistry totaling 274 analytes (polycyclic aromatic hydrocarbons, organochlorine compounds, polychlorinated biphenyls, polybrominated diphenyl ethers, trace elements, and current-use pesticides) and a mixture assessment based on the ratios of detected compounds to available effects-based benchmarks...
December 1, 2017: Science of the Total Environment
Jianqing Fan, Quefeng Li, Yuyan Wang
Data subject to heavy-tailed errors are commonly encountered in various scientific fields. To address this problem, procedures based on quantile regression and Least Absolute Deviation (LAD) regression have been developed in recent years. These methods essentially estimate the conditional median (or quantile) function. They can be very different from the conditional mean functions, especially when distributions are asymmetric and heteroscedastic. How can we efficiently estimate the mean regression functions in ultra-high dimensional setting with existence of only the second moment? To solve this problem, we propose a penalized Huber loss with diverging parameter to reduce biases created by the traditional Huber loss...
January 2017: Journal of the Royal Statistical Society. Series B, Statistical Methodology
Franziska Jannasch, Janine Kröger, Matthias B Schulze
Background: Different methodologic approaches for constructing dietary patterns and differences in their composition limit conclusions on healthful patterns for diabetes prevention. Objective: We summarized evidence from prospective studies that examined associations of dietary patterns with type 2 diabetes by considering different methodologic approaches. Methods: The literature search (MEDLINE and Web of Science) identified prospective studies (cohorts or trials) that associated dietary patterns with diabetes incidence in nondiabetic and apparently healthy participants...
June 2017: Journal of Nutrition
Alessandra C de Paula Silveira, Sacha B Chaves, Leandro A Hilgert, Ana Paula D Ribeiro
STATEMENT OF PROBLEM: The precision of fit of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) complete crowns is affected by digital impression and restorative material. PURPOSE: The purpose of this in vitro study was to evaluate by microcomputed tomography (μCT) the marginal and internal adaptation of composite resin and ceramic complete crowns fabricated with 2 different intraoral cameras and 2 restorative materials. MATERIAL AND METHODS: Ten extracted human third molars received crown preparations...
March 2017: Journal of Prosthetic Dentistry
Degui Li, Runze Li
In this paper, we study the local polynomial composite quantile regression (CQR) smoothing method for the nonlinear and nonparametric models under the Harris recurrent Markov chain framework. The local polynomial CQR regression method is a robust alternative to the widely-used local polynomial method, and has been well studied in stationary time series. In this paper, we relax the stationarity restriction on the model, and allow that the regressors are generated by a general Harris recurrent Markov process which includes both the stationary (positive recurrent) and nonstationary (null recurrent) cases...
September 2016: Journal of Econometrics
Amit G Singal, Peng Zhang, Akbar K Waljee, Lakshmi Ananthakrishnan, Neehar D Parikh, Pratima Sharma, Pranab Barman, Venkataramu Krishnamurthy, Lu Wang, Stewart C Wang, Grace L Su
OBJECTIVES: Existing prognostic models for patients with hepatocellular carcinoma (HCC) have limitations. Analytic morphomics, a novel process to measure body composition using computational image-processing algorithms, may offer further prognostic information. The aim of this study was to develop and validate a prognostic model for HCC patients using body composition features and objective clinical information. METHODS: Using computed tomography scans from a cohort of HCC patients at the VA Ann Arbor Healthcare System between January 2006 and December 2013, we developed a prognostic model using analytic morphomics and routine clinical data based on multivariate Cox regression and regularization methods...
May 26, 2016: Clinical and Translational Gastroenterology
James P Herrera
Models of ecological community assembly predict how communities of interacting organisms may be shaped by abiotic and biotic factors. Competition and environmental filtering are the predominant factors hypothesized to explain community assembly. This study tested the effects of habitat, phylogenetic and phenotypic trait predictors on species co-occurrence patterns and abundances, with the endemic primates of Madagascar as an empirical system. The abundance of 11 primate species was estimated along gradients of elevation, food resource abundance and anthropogenic habitat disturbance at local scales in south-east Madagascar...
July 2016: Journal of Animal Ecology
Darrell J Gaskin, Hossein Zare, Adil H Haider, Thomas A LaVeist
OBJECTIVE: To explore the association between quality of care for surgical and pneumonia patients and the racial/ethnic composition of hospitals' patients. DATA SOURCE: Our primary data were surgical and pneumonia processes of care indicators from the 2012 Medicare Hospital Compare Data. We merged this data with information from the 2011 American Hospital Association Annual Survey of Hospitals. We computed the racial and ethnic composition of hospital patients using 2008 data from the Healthcare Costs and Utilization Project...
June 2016: Health Services Research
Ping Shi, J Max Goodson, Mor-Li Hartman, Hatice Hasturk, Tina Yaskell, Jorel Vargas, Maryann Cugini, Roula Barake, Osama Alsmadi, Sabiha Al-Mutawa, Jitendra Ariga, Pramod Soparkar, Jawad Behbehani, Kazem Behbehani, Francine Welty
BACKGROUND: Binary definitions of the metabolic syndrome based on the presence of a particular number of individual risk factors are limited, particularly in the pediatric population. To address this limitation, we aimed at constructing composite and continuous metabolic syndrome scores (cmetS) to represent an overall measure of metabolic syndrome (MetS) in a large cohort of metabolically at-risk children, focusing on the use of the usual clinical parameters (waist circumference (WC) and systolic blood pressure (SBP), supplemented with two salivary surrogate variables (glucose and high density lipoprotein cholesterol (HDLC)...
2015: PloS One
Grace H Lo, Timothy E McAlindon, Gillian A Hawker, Jeffrey B Driban, Lori Lyn Price, Jing Song, Charles B Eaton, Marc C Hochberg, Rebecca D Jackson, C Kent Kwoh, Michael C Nevitt, Dorothy D Dunlop
OBJECTIVE: Pain is not always correlated with severity of radiographic osteoarthritis (OA), possibly because people modify activities to manage symptoms. Measures of symptoms that consider pain in the context of activity level may therefore provide greater discrimination than a measure of pain alone. We undertook this study to compare discrimination provided by a measure of pain alone with that provided by combined measures of pain in the context of physical activity across radiographic OA severity levels...
November 2015: Arthritis & Rheumatology
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