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https://www.readbyqxmd.com/read/27900633/two-phase-outcome-dependent-studies-for-failure-times-and-testing-for-effects-of-expensive-covariates
#1
J F Lawless
Two- or multi-phase study designs are often used in settings involving failure times. In most studies, whether or not certain covariates are measured on an individual depends on their failure time and status. For example, when failures are rare, case-cohort or case-control designs are used to increase the number of failures relative to a random sample of the same size. Another scenario is where certain covariates are expensive to measure, so they are obtained only for selected individuals in a cohort. This paper considers such situations and focuses on cases where we wish to test hypotheses of no association between failure time and expensive covariates...
November 29, 2016: Lifetime Data Analysis
https://www.readbyqxmd.com/read/27894561/apneic-oxygenation-may-not-prevent-severe-hypoxemia-during-rapid-sequence-intubation-a-retrospective-helicopter-emergency-medical-service-study
#2
Sattha Riyapan, Jeffrey Lubin
OBJECTIVE: This study sought to determine the effectiveness of apneic oxygenation in preventing hypoxemia during prehospital rapid sequence intubation (RSI). METHODS: We performed a case-cohort study using a pre-existing database looking at intubation management by a single helicopter emergency medical service between July 2013 and June 2015. Apneic oxygenation using high-flow nasal cannula (15 L/min) was introduced to the standard RSI protocol in July 2014. Severe hypoxemia was defined as an incidence of oxygen saturation less than 90%...
November 2016: Air Medical Journal
https://www.readbyqxmd.com/read/27893808/common-polymorphisms-in-the-5-lipoxygenase-pathway-and-risk-of-incident-myocardial-infarction-a-danish-case-cohort-study
#3
Anders Gammelmark, Michael S Nielsen, Søren Lundbye-Christensen, Anne Tjønneland, Erik B Schmidt, Kim Overvad
BACKGROUND: The 5-lipoxygenase pathway (5-LOX) has been implicated in the development of cardiovascular disease and studies have suggested that genetic polymorphisms related to key enzymes in this pathway may confer risk of myocardial infarction (MI). This study investigated the association of pre-selected genetic polymorphisms in four candidate genes of 5-LOX (arachidonate 5-lipoxygenase and its activating protein (ALOX-5 and FLAP), leukotriene A4 hydroxylase (LTA4-H) and leukotriene C4 synthase (LTC4-S)) with incident MI...
2016: PloS One
https://www.readbyqxmd.com/read/27864342/systemic-levels-of-estrogens-and-pge2-synthesis-in-relation-to-postmenopausal-breast-cancer-risk
#4
Sangmi Kim, Jeff Campbell, Wonsuk Yoo, Jack A Taylor, Dale P Sandler
BACKGROUND: Prostaglandin E2 (PGE2) induces aromatase expression in adipose tissue leading to increased estrogen production that may promote the development and progression of breast cancer. However, few studies have simultaneously investigated systemic levels of PGE2 and estrogen in relation to postmenopausal breast cancer risk. METHODS: Here we determined urinary estrogen metabolites (EMs) using mass spectrometry in a case-cohort study (295 incident breast cancer cases and 294 subcohort members), and using linear regression estimated the effect of urinary levels of a major PGE2 metabolite (PGE-M) on EMs...
November 18, 2016: Cancer Epidemiology, Biomarkers & Prevention
https://www.readbyqxmd.com/read/27856445/fetuin-a-and-risk-of-diabetes-independent-of-liver-fat-content-the-multi-ethnic-study-of-atherosclerosis
#5
Sarah A Aroner, Kenneth J Mukamal, David E St-Jules, Matthew J Budoff, Ronit Katz, Michael H Criqui, Matthew A Allison, Ian H de Boer, David S Siscovick, Joachim H Ix, Majken K Jensen
Fetuin-A is a hepatic secretory protein and a novel risk factor for diabetes. However, it remains unclear whether the association between high levels of fetuin-A and diabetes can be attributed to nonalcoholic fatty liver disease. We conducted a case-cohort study among 1,957 subcohort members and 455 incident diabetes cases in the Multi-Ethnic Study of Atherosclerosis, a multicenter US study of Caucasian, African-American, Hispanic, and Chinese-American adults aged 45-84 years. Serum fetuin-A and computed tomography-determined liver fat content were measured from samples collected at baseline (2000-2002)...
November 17, 2016: American Journal of Epidemiology
https://www.readbyqxmd.com/read/27832250/association-of-serum-level-of-vitamin-d-at-diagnosis-with-breast-cancer-survival-a-case-cohort-analysis-in-the-pathways-study
#6
Song Yao, Marilyn L Kwan, Isaac J Ergas, Janise M Roh, Ting-Yuan David Cheng, Chi-Chen Hong, Susan E McCann, Li Tang, Warren Davis, Song Liu, Charles P Quesenberry, Marion M Lee, Christine B Ambrosone, Lawrence H Kushi
Importance: There are long-standing interests in the potential benefits of vitamin D for preventing breast cancer recurrence and mortality, yet data from prospective cohort studies are limited. Objective: To investigate a serum biomarker of vitamin D status, 25-hydroxyvitamin D (25OHD) measured at the time of breast cancer diagnosis, to determine the association with prognosis. Design, Setting, and Participants: The Pathways Study is a prospective cohort study of breast cancer survivors established in 2006...
November 10, 2016: JAMA Oncology
https://www.readbyqxmd.com/read/27826924/profiling-circulating-mirnas-from-the-plasma-of-individuals-with-metabolic-syndrome
#7
Sadhbh O'Neill, Lorraine O'Driscoll
The technique of RT-qPCR (real time-quantitative polymerase chain reaction) is invaluable in miRNA research both at the profiling and individual RT-qPCR stages. At the profiling stage, numerous miRNAs are looked at in the plasma of numerous individuals from two or more cohorts (i.e., control vs. case). The miRNAs of interest would be either upregulated or downregulated by more than twofold in the case cohort compared to the control cohort. Profiling human specimens for miRNA biomarkers has exploded over the last decade, with researchers profiling plasma, serum, urine, and also the miRNA content of extracellular vesicles, which are also isolated from human specimens...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27818017/low-maternal-25-hydroxyvitamin-d-concentration-increases-the-risk-of-severe-and-mild-preeclampsia
#8
Katharyn M Baca, Hyagriv N Simhan, Robert W Platt, Lisa M Bodnar
PURPOSE: The objective of this case-cohort study was to evaluate the relationship between maternal 25-hydroxyvitamin D (25(OH)D) concentration and preeclampsia overall and by severity. METHODS: From an eligible cohort of 12,861 women who had serum banked from aneuploidy screening in Pittsburgh, Pennsylvania from 1999 to 2010, we randomly sampled a subcohort of 2327 pregnancies and all remaining preeclampsia cases (n = 650 cases). Preeclampsia (defined as new-onset hypertension and proteinuria) and its mild and severe forms were identified using ICD-9 codes...
December 2016: Annals of Epidemiology
https://www.readbyqxmd.com/read/27798002/-omics-biomarkers-associated-with-chronic-low-back-pain-protocol-of-a-retrospective-longitudinal-study
#9
Massimo Allegri, Manuela De Gregori, Cristina E Minella, Catherine Klersy, Wei Wang, Moira Sim, Christian Gieger, Judith Manz, Iain K Pemberton, Jane MacDougall, Frances Mk Williams, Jan Van Zundert, Klaas Buyse, Gordan Lauc, Ivan Gudelj, Dragan Primorac, Andrea Skelin, Yurii S Aulchenko, Lennart C Karssen, Leonardo Kapural, Richard Rauck, Guido Fanelli
INTRODUCTION: Chronic low back pain (CLBP) produces considerable direct costs as well as indirect burdens for society, industry and health systems. CLBP is characterised by heterogeneity, inclusion of several pain syndromes, different underlying molecular pathologies and interaction with psychosocial factors that leads to a range of clinical manifestations. There is still much to understand in the underlying pathological processes and the non-psychosocial factors which account for differences in outcomes...
October 19, 2016: BMJ Open
https://www.readbyqxmd.com/read/27796501/higher-serum-asymmetric-dimethylarginine-is-related-to-higher-risk-of-heart-failure-in-the-epic-potsdam-study
#10
Janine Wirth, Dorothee Atzler, Romina di Giuseppe, Kathrin Cordts, Juliane Menzel, Rainer H Böger, Heiner Boeing, Cornelia Weikert, Edzard Schwedhelm
L-Arginine is the substrate of endothelial nitric oxide (NO) synthase forming NO which inherits various biological cardio-protective functions. The dimethylarginines asymmetric (ADMA) and symmetric dimethylarginine (SDMA) can impair the synthesis of NO and are elevated in patients with cardiovascular disease, including heart failure (HF). We investigated the association between dimethylarginines and HF risk in a case-cohort study of the European Prospective Investigation into Cancer and Nutrition (n = 27,548), comprising a random subcohort (n = 2224 including 19 HF cases), and all remaining HF cases (n = 176) that occurred within 8...
October 28, 2016: Amino Acids
https://www.readbyqxmd.com/read/27777633/uncovering-obsessive-compulsive-disorder-risk-genes-in-a-pediatric-cohort-by-high-resolution-analysis-of-copy-number-variation
#11
Matthew J Gazzellone, Mehdi Zarrei, Christie L Burton, Susan Walker, Mohammed Uddin, S M Shaheen, Julie Coste, Rageen Rajendram, Reva J Schachter, Marlena Colasanto, Gregory L Hanna, David R Rosenberg, Noam Soreni, Kate D Fitzgerald, Christian R Marshall, Janet A Buchanan, Daniele Merico, Paul D Arnold, Stephen W Scherer
BACKGROUND: Obsessive-compulsive disorder (OCD) is a heterogeneous neuropsychiatric condition, thought to have a significant genetic component. When onset occurs in childhood, affected individuals generally exhibit different characteristics from adult-onset OCD, including higher prevalence in males and increased heritability. Since neuropsychiatric conditions are associated with copy number variations (CNVs), we considered their potential role in the etiology of OCD. METHODS: We genotyped 307 unrelated pediatric probands with idiopathic OCD (including 174 that were part of complete parent-child trios) and compared their genotypes with those of 3861 population controls, to identify rare CNVs (<0...
2016: Journal of Neurodevelopmental Disorders
https://www.readbyqxmd.com/read/27774627/a-case-cohort-approach-for-multi-state-models-in-hospital-epidemiology
#12
Maja von Cube, Martin Schumacher, Mercedes Palomar-Martinez, Pedro Olaechea-Astigarraga, Francisco Alvarez-Lerma, Martin Wolkewitz
Analysing the determinants and consequences of hospital-acquired infections involves the evaluation of large cohorts. Infected patients in the cohort are often rare for specific pathogens, because most of the patients admitted to the hospital are discharged or die without such an infection. Death and discharge are competing events to acquiring an infection, because these individuals are no longer at risk of getting a hospital-acquired infection. Therefore, the data is best analysed with an extended survival model - the extended illness-death model...
October 24, 2016: Statistics in Medicine
https://www.readbyqxmd.com/read/27773353/suicide-in-tourette-s-and-chronic-tic-disorders
#13
Lorena Fernández de la Cruz, Mina Rydell, Bo Runeson, Gustaf Brander, Christian Rück, Brian M D'Onofrio, Henrik Larsson, Paul Lichtenstein, David Mataix-Cols
BACKGROUND: Persons with neuropsychiatric disorders are at increased risk of suicide, but there is little data concerning Tourette's and chronic tic disorders (TD/CTD). We aimed to quantify the risk of suicidal behavior in a large nationwide cohort of patients with TD/CTD, establish the contribution of psychiatric comorbidity to this risk, and identify predictors of suicide. METHODS: Using a validated algorithm, we identified 7736 TD/CTD cases in the Swedish National Patient Register during a 44-year period (1969-2013)...
August 26, 2016: Biological Psychiatry
https://www.readbyqxmd.com/read/27768709/maternal-and-birth-characteristics-and-childhood-embryonal-solid-tumors-a-population-based-report-from-brazil
#14
Neimar de Paula Silva, Rejane de Souza Reis, Rafael Garcia Cunha, Júlio Fernando Pinto Oliveira, Marceli de Oliveira Santos, Maria S Pombo-de-Oliveira, Beatriz de Camargo
BACKGROUND: Several maternal and birth characteristics have been reported to be associated with an increased risk of many childhood cancers. Our goal was to evaluate the risk of childhood embryonal solid tumors in relation to pre- and perinatal characteristics. METHODS: A case-cohort study was performed using two population-based datasets, which were linked through R software. Tumors were classified as central nervous system (CNS) or non-CNS-embryonal (retinoblastoma, neuroblastoma, renal tumors, germ cell tumors, hepatoblastoma and soft tissue sarcoma)...
2016: PloS One
https://www.readbyqxmd.com/read/27765293/effectiveness-of-one-dose-of-oral-cholera-vaccine-in-response-to-an-outbreak-a-case-cohort-study
#15
Andrew S Azman, Lucy A Parker, John Rumunu, Fisseha Tadesse, Francesco Grandesso, Lul L Deng, Richard Laku Lino, Bior K Bior, Michael Lasuba, Anne-Laure Page, Lameck Ontweka, Augusto E Llosa, Sandra Cohuet, Lorenzo Pezzoli, Dossou Vincent Sodjinou, Abdinasir Abubakar, Amanda K Debes, Allan M Mpairwe, Joseph F Wamala, Christine Jamet, Justin Lessler, David A Sack, Marie-Laure Quilici, Iza Ciglenecki, Francisco J Luquero
BACKGROUND: Oral cholera vaccines represent a new effective tool to fight cholera and are licensed as two-dose regimens with 2-4 weeks between doses. Evidence from previous studies suggests that a single dose of oral cholera vaccine might provide substantial direct protection against cholera. During a cholera outbreak in May, 2015, in Juba, South Sudan, the Ministry of Health, Médecins Sans Frontières, and partners engaged in the first field deployment of a single dose of oral cholera vaccine to enhance the outbreak response...
November 2016: Lancet Global Health
https://www.readbyqxmd.com/read/27756783/plasma-lipidomic-profiles-improve-upon-traditional-risk-factors-for-the-prediction-of-cardiovascular-events-in-type-2-diabetes
#16
Zahir H Alshehry, Piyushkumar A Mundra, Christopher K Barlow, Natalie A Mellett, Gerard Wong, Malcolm J McConville, John Simes, Andrew M Tonkin, David R Sullivan, Elizabeth H Barnes, Paul J Nestel, Bronwyn A Kingwell, Michel Marre, Bruce Neal, Neil R Poulter, Anthony Rodgers, Bryan Williams, Sophia Zoungas, Graham S Hillis, John Chalmers, Mark Woodward, Peter J Meikle
BACKGROUND: -Clinical lipid measurements do not show the full complexity of the altered lipid metabolism associated with diabetes or cardiovascular disease. Lipidomics enables the assessment of hundreds of lipid species as potential markers for disease risk. METHODS: -Plasma lipid species (310) were measured by a targeted lipidomic analysis with liquid chromatography electrospray ionisation-tandem mass spectrometry on a case-cohort (n=3,779) subset from the ADVANCE (Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation) trial...
October 18, 2016: Circulation
https://www.readbyqxmd.com/read/27754924/urinary-cadmium-and-breast-cancer-a-prospective-danish-cohort-study
#17
Kirsten T Eriksen, Jane A McElroy, James M Harrington, Keith E Levine, Camilla Pedersen, Mette Sørensen, Anne Tjønneland, Jaymie R Meliker, Ole Raaschou-Nielsen
BACKGROUND: Cadmium is a human lung carcinogen, and recent evidence suggests it may play a role in hormone-related cancers because of its estrogenic activity. Case-control studies consistently show higher cadmium concentrations in urine from women diagnosed with breast cancer compared with control women. Our aim was to investigate the association between urinary cadmium and breast cancer in a prospective design. METHODS: We conducted a case-cohort study using the population-based Danish Diet Cancer and Health Cohort...
February 2017: Journal of the National Cancer Institute
https://www.readbyqxmd.com/read/27748414/prospective-study-of-serum-b-vitamins-levels-and-oesophageal-and-gastric-cancers-in-china
#18
Jiansong Ren, Gwen Murphy, Jinhu Fan, Sanford M Dawsey, Philip R Taylor, Jacob Selhub, Youlin Qiao, Christian C Abnet
B vitamins play an essential role in DNA synthesis and methylation, and may protect against oesophageal and gastric cancers. In this case-cohort study, subjects were enrolled from the General Population Nutrition Intervention Trial in Linxian, China. Subjects included 498 oesophageal squamous cell carcinomas (OSCCs), 255 gastric cardia adenocarcinomas (GCAs), and an age- and sex-matched sub-cohort of 947 individuals. Baseline serum riboflavin, pyridoxal phosphate (PLP), folate, vitamin B12, and flavin mononucleotide (FMN) were measured for all subjects...
October 17, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27743920/development-and-validation-of-a-24-gene-predictor-of-response-to-postoperative-radiotherapy-in-prostate-cancer-a-matched-retrospective-analysis
#19
Shuang G Zhao, S Laura Chang, Daniel E Spratt, Nicholas Erho, Menggang Yu, Hussam Al-Deen Ashab, Mohammed Alshalalfa, Corey Speers, Scott A Tomlins, Elai Davicioni, Adam P Dicker, Peter R Carroll, Matthew R Cooperberg, Stephen J Freedland, R Jeffrey Karnes, Ashley E Ross, Edward M Schaeffer, Robert B Den, Paul L Nguyen, Felix Y Feng
BACKGROUND: Postoperative radiotherapy has an important role in the treatment of prostate cancer, but personalised patient selection could improve outcomes and spare unnecessary toxicity. We aimed to develop and validate a gene expression signature to predict which patients would benefit most from postoperative radiotherapy. METHODS: Patients were eligible for this matched, retrospective study if they were included in one of five published US studies (cohort, case-cohort, and case-control studies) of patients with prostate adenocarcinoma who had radical prostatectomy (with or without postoperative radiotherapy) and had gene expression analysis of the tumour, with long-term follow-up and complete clinicopathological data...
October 12, 2016: Lancet Oncology
https://www.readbyqxmd.com/read/27734520/comparisons-of-risk-prediction-methods-using-nested-case-control-data
#20
Agus Salim, Bénédicte Delcoigne, Krystyn Villaflores, Woon-Puay Koh, Jian-Min Yuan, Rob M van Dam, Marie Reilly
Using both simulated and real datasets, we compared two approaches for estimating absolute risk from nested case-control (NCC) data and demonstrated the feasibility of using the NCC design for estimating absolute risk. In contrast to previously published results, we successfully demonstrated not only that data from a matched NCC study can be used to unbiasedly estimate absolute risk but also that matched studies give better statistical efficiency and classify subjects into more appropriate risk categories. Our result has implications for studies that aim to develop or validate risk prediction models...
October 13, 2016: Statistics in Medicine
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