Search results for "Biostatistics"
showing 10 items of 124 documents
An Empirical Evaluation of the Utility of Convex Hull and Standard Ellipse Areas for Assessing Population Niche Widths from Stable Isotope Data
2013
Stable isotope analyses are increasingly employed to characterise population niche widths. The convex hull area (TA) in a δ¹³C–δ¹⁵N biplot has been used as a measure of isotopic niche width, but concerns exist over its dependence on sample size and associated difficulties in among-population comparisons. Recently a more robust method was proposed for estimating and comparing isotopic niche widths using standard ellipse areas (SEA), but this approach has yet to be tested with empirical stable isotope data. The two methods measure different kind of isotopic niche areas, but both are now widely used to characterise isotopic niche widths of populations. We used simulated data and an extensive e…
Using the Intervention Mapping protocol to develop a family-based intervention for improving lifestyle habits among overweight and obese children: st…
2016
Abstract Background In light of the high prevalence of childhood overweight and obesity, there is a need of developing effective prevention programs to address the rising prevalence and the concomitant health consequences. The main aim of the present study is to systematically develop and implement a tailored family-based intervention for improving lifestyle habits among overweight and obese children, aged 6–10 years old, enhancing parental self-efficacy, family engagement and parent-child interaction. A subsidiary aim of the intervention study is to reduce the prevalence of overweight and obesity among those participating in the intervention study. Methods/design The Intervention Mapping p…
Early food for future health: a randomized controlled trial evaluating the effect of an eHealth intervention aiming to promote healthy food habits fr…
2017
Childhood overweight and obesity is a global public health challenge. Primary prevention initiatives targeting parents have been called for to encourage a positive feeding environment and healthy eating habits that may lay a good foundation for future health. At the same time, there is a need for interventions which combine accessibility and scalability with cost effectiveness. Today’s parents are extensive Internet-users, but only a few randomized controlled trials have investigated the use of Internet to promote healthy eating habits in early childhood. In Early Food for Future Health we have developed and will evaluate an Internet-based tool for parents of children between 6 and 12 month…
Towards development of a statistical framework to evaluate myotonic dystrophy type 1 mRNA biomarkers in the context of a clinical trial
2020
AbstractMyotonic dystrophy type 1 (DM1) is a rare genetic disorder, characterised by muscular dystrophy, myotonia, and other symptoms. DM1 is caused by the expansion of a CTG repeat in the 3’-untranslated region of DMPK. Longer CTG expansions are associated with greater symptom severity and earlier age at onset. The primary mechanism of pathogenesis is thought to be mediated by a gain of function of the CUG-containing RNA, that leads to trans-dysregulation of RNA metabolism of many other genes. Specifically, the alternative splicing (AS) and alternative polyadenylation (APA) of many genes is known to be disrupted. In the context of clinical trials of emerging DM1 treatments, it is important…
Evaluation of tumor immune contexture among intrinsic molecular subtypes helps to predict outcome in early breast cancer
2021
BackgroundThe prognosis of early breast cancer is linked to clinic-pathological stage and the molecular characteristics of intrinsic tumor cells. In some patients, the amount and quality of tumor-infiltrating immune cells appear to affect long term outcome. We aimed to propose a new tool to estimate immune infiltrate, and link these factors to patient prognosis according to breast cancer molecular subtypes.MethodsWe performed in silico analyses in more than 2800 early breast cancer transcriptomes with corresponding clinical annotations. We first developed a new gene expression deconvolution algorithm that accurately estimates the quantity of immune cell populations (tumor immune contexture,…
The IASLC Lung Cancer Staging Project: Proposals for Revision of the TNM Stage Groupings in the Forthcoming (Eighth) Edition of the TNM Classificatio…
2016
AbstractThe IASLC Staging and Prognostic Factors Committee has collected a new database of 94,708 cases donated from 35 sources in 16 countries around the globe. This has now been analysed by our statistical partners at Cancer Research And Biostatistics and, in close collaboration with the members of the committee proposals have been developed for the T, N, and M categories of the 8th edition of the TNM Classification for lung cancer due to be published late 2016. In this publication we describe the methods used to evaluate the resultant Stage groupings and the proposals put forward for the 8th edition.
Stagewise pseudo-value regression for time-varying effects on the cumulative incidence
2015
In a competing risks setting, the cumulative incidence of an event of interest describes the absolute risk for this event as a function of time. For regression analysis, one can either choose to model all competing events by separate cause-specific hazard models or directly model the association between covariates and the cumulative incidence of one of the events. With a suitable link function, direct regression models allow for a straightforward interpretation of covariate effects on the cumulative incidence. In practice, where data can be right-censored, these regression models are implemented using a pseudo-value approach. For a grid of time points, the possibly unobserved binary event s…
Pathways of care for HIV infected children in Beira, Mozambique: pre-post intervention study to assess impact of task shifting
2018
Abstract Background In 2013, Mozambique implemented task-shifting (TS) from clinical officers to maternal and child nurses to improve care for HIV positive children < 5 years old. A retrospective, pre-post intervention study was designed to evaluate effectiveness of a new pathway of care in a sample of Beira District Local Health Facilities (LHFs), the primary, local, community healthcare services. Methods The study was conducted by accessing registries of At Risk Children Clinics (ARCCs) and HIV Health Services. Two time periods, pre- and post-intervention, were compared using a set of endpoints. Variables distribution was explored using descriptive statistics. T-student, Mann Whitney and …