351 research outputs found

    Evidence to support climate change adaptation in Lesotho, Malawi and Swaziland

    Get PDF
    In Lesotho, Malawi and Swaziland, moderately vulnerable households are likely to become highly vulnerable with changes in climate. The project aims to generate scientific understanding of localized climate scenarios in the three countries; integrate localized climate scenarios with crop growth and adaptation models; provide district-wide household vulnerability information; and determine the socio-economic feasibility of cropping options. Evidence-based policy implications are derived from the study; for instance, the importance of institutional systems that can disseminate timely climate information to smallholders, including informed planting dates

    Adiposity in childhood brain tumors: A report from the Canadian Study of determinants of endometabolic health in children (CanDECIDE Study)

    Get PDF
    Children with brain tumors (CBT) are at high risk of cardiovascular diseases and type 2 diabetes compared to the general population. Recently, adiposity has been reported to be more informative for cardiometabolic risk stratification than body mass index (BMI) in the general population. The goal of this study is to describe the adiposity phenotype in CBT, and to establish adiposity determinants. We recruited CBT (n = 56) and non-cancer controls (n = 106). Percent body fat (%FM), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were measured to determine total and central adiposity, respectively. Regression analyses were used to evaluate adiposity determinants. CBT had higher total and central adiposity compared to non-cancer controls despite having similar BMI measurements. Those with tumors at the supratentorial region had increased total and central adiposity, while those who received radiotherapy had increased total adiposity. In conclusion, CBT have increased total and central adiposity in the presence of similar BMI levels when compared to non-cancer controls. Adiposity, especially central adiposity, is a potential cardiometabolic risk factor present relatively early in life in CBT. Defining interventions to target adiposity may improve long-term outcomes by preventing cardiometabolic disorders in CBT

    Structured diet and exercise guidance in pregnancy to improve health in women and their offspring: study protocol for the Be Healthy in Pregnancy (BHIP) randomized controlled trial

    Get PDF
    BackgroundEvidence from epidemiological and animal studies support the concept of programming fetal, neonatal, and adult health in response to in utero exposures such as maternal obesity and lifestyle variables. Excess gestational weight gain (GWG), maternal physical activity, and sub-optimal and excess nutrition during pregnancy may program the offspring\u27s risk of obesity. Maternal intake of dairy foods rich in high-quality proteins, calcium, and vitamin D may influence later bone health status. Current clinical practice guidelines for managing GWG are not founded on randomized trials and lack specific active intervention ingredients. The Be Healthy in Pregnancy (BHIP) study is a randomized controlled trial (RCT) designed to test the effectiveness of a novel structured and monitored Nutrition + Exercise intervention in pregnant women of all pre-pregnancy weight categories (except extreme obesity), delivered through prenatal care in community settings (rather than in hospital settings), on the likelihood of women achieving recommended GWG and a benefit to bone status of offspring and mother at birth and sixmonths postpartum.MethodsThe BHIP study is a two-site RCT that will recruit up to 242 participants aged \u3e18years at 12-17 weeks of gestation. After baseline measures, participants are randomized to either a structured and monitored Nutrition + Exercise (intervention) or usual care (control) program for the duration of their pregnancy. The primary outcome of the study is the percent of women who achieve GWG within the Institute of Medicine (IOM) guidelines. The secondary outcomes include: (1) maternal bone status via blood bone biomarkers during pregnancy; (2) infant bone status in cord blood; (3) mother and infant bone status measured by dual-energy absorptiometry scanning (DXA scan) at sixmonths postpartum; (4) other measures including maternal blood pressure, blood glucose and lipid profiles, % body fat, and postpartum weight retention; and (5) infant weight z-scores and fat mass at sixmonths of age.DiscussionIf effective, this RCT will generate high-quality evidence to refine the nutrition guidelines during pregnancy to improve the likelihood of women achieving recommended GWG. It will also demonstrate the importance of early nutrition on bone health in the offspring

    Pilot and feasibility studies: extending the conceptual framework

    Get PDF
    In 2016, we published a conceptual framework outlining the conclusions of our work in defining pilot and feasibility studies. Since then, the CONSORT extension to randomised pilot and feasibility trials has been published and there have been further developments in the pilot study landscape. In this paper, we revisit and extend our framework to incorporate the various feasibility pathways open to researchers, which include internal pilot studies. We consider, with examples, when different approaches to feasibility and pilot studies are more effective and efficient, taking into account the pragmatic decisions that may need to be made. The ethical issues involved in pilot studies are discussed. We end with a consideration of the funders’ perspective in making difficult resource decisions to include feasibility work and the policy implications of these; throughout, we provide examples of the uncertainties and compromises that researchers have to navigate to make progress in the most efficient way

    Piloting a tool for informed consent comprehension in a cardiovascular clinical trial in South Africa: An IMPI-2 pilot trial substudy (ICC Study)

    Get PDF
    Background. Informed consent is a key requirement in research. However, the comprehension of information presented is rarely evaluated prior to or during the research. Ensuring that participants understand the key issues in trials is important, not just for ethical reasons, but also because it can help set patient expectations. We evaluated the feasibility of using the University of California Brief Assessment of Capacity to Consent (UBACC) questionnaire to guide informed consent comprehension in the pilot study for the second Investigation of the Management of Pericarditis in Africa (IMPI-2) trial. IMPI-2 is a randomised control trial (RCT) on the use of alteplase-facilitated pericardial drainage, compared with routine care among patients with large pericardial effusion. We used an abbreviated version of the UBACC to evaluate participant comprehension of key elements of the consent documentation and to guide discussions. Method. Comprehension was assessed using a 10-item UBACC at baseline, 6 weeks, 3 months and 6 months follow-up to reiterate the information about the trial. Each response was scored from 0 to 3 and the sum at each visit was recorded to represent comprehension. A UBACC score ≄25 was considered adequate comprehension. Bivariate logistic regression was performed to evaluate comprehension over time. A multivariate analysis was conducted to identify predictors of UBACC score. Results. The Informed Consent Comprehension (ICC) Study included 71 participants with a median age of 42 years; 45% were females and 49% had at least a secondary level of education. Level of comprehension improved with time; the odds of passing the evaluation at baseline compared with 6 months was higher (odds ratio (OR) 1.39, 95% confidence interval (CI) 1.17 - 1.65, p<0.001). Not using interpreters and having a secondary level of education were associated with higher comprehension. Despite knowing that they were participating in research, many participants still did not accept that the trial drug may have no effect. Conclusion. It is feasible to use the UBACC questionnaire for informed consent comprehension evaluation in RCTs. Repeated learning during follow-up improves comprehension over time, while a low level of education and use of interpreters reduces comprehension

    Influence of radiation damage on xenon diffusion in silicon carbide

    Get PDF
    Diffusion of xenon in poly and single crystalline silicon carbide and the possible influence of radiation damage on it are investigated. For this purpose 360 keV xenon ions were implanted in commercial 6H-SiC and CVD-SiC wafers at room temperature, 350 °C and 600 °C. Width broadening of the implantation profiles and xenon retention during isochronal and isothermal annealing up to temperatures of 1500 °C was determined by RBS-analysis, whilst in the case of 6H-SiC damage profiles were simultaneously obtained by aparticle channelling. No diffusion or xenon loss was detected in the initially amorphized and eventually recrystallized surface layer of cold implanted 6H-SiC during annealing up to 1200 °C. Above that temperature serious erosion of the implanted surface occurred, which made any analysis impossible. No diffusion or xenon loss is detected in the hot implanted 6H-SiC samples during annealing up to 1400 °C. Radiation damage dependent grain boundary diffusion is observed at 1300 °C in CVD-SiC.National Research Foundation and the Bundesministerium fĂŒr Bildung und Forschunghttp://www.elsevier.com/locate/nimbhb201

    Progression from external pilot to definitive randomised controlled trial : a methodological review of progression criteria reporting

    Get PDF
    Objectives: Prespecified progression criteria can inform the decision to progress from an external randomised pilot trial to a definitive randomised controlled trial. We assessed the characteristics of progression criteria reported in external randomised pilot trial protocols and results publications, including whether progression criteria were specified a priori and mentioned in prepublication peer reviewer reports. Study design: Methodological review. Methods: We searched four journals through PubMed: British Medical Journal Open, Pilot and Feasibility Studies, Trials and Public Library of Science One. Eligible publications reported external randomised pilot trial protocols or results, were published between January 2018 and December 2019 and reported progression criteria. We double data extracted 25% of the included publications. Here we report the progression criteria characteristics. Results: We included 160 publications (123 protocols and 37 completed trials). Recruitment and retention were the most frequent indicators contributing to progression criteria. Progression criteria were mostly reported as distinct thresholds (eg, achieving a specific target; 133/160, 83%). Less than a third of the planned and completed pilot trials that included qualitative research reported how these findings would contribute towards progression criteria (34/108, 31%). The publications seldom stated who established the progression criteria (12/160, 7.5%) or provided rationale or justification for progression criteria (44/160, 28%). Most completed pilot trials reported the intention to proceed to a definitive trial (30/37, 81%), but less than half strictly met all of their progression criteria (17/37, 46%). Prepublication peer reviewer reports were available for 153/160 publications (96%). Peer reviewer reports for 86/153 (56%) publications mentioned progression criteria, with peer reviewers of 35 publications commenting that progression criteria appeared not to be specified. Conclusions: Many external randomised pilot trial publications did not adequately report or propose prespecified progression criteria to inform whether to proceed to a future definitive randomised controlled trial

    Trials

    Get PDF
    BACKGROUND: An international workshop on population health intervention research (PHIR) was organized to foster exchanges between experts from different disciplines and different fields. AIMS: This paper aims to summarize the discussions around one of the issues addressed: the place or role of pilot studies in PHIR. Pilot studies are well-established in biomedical research, but the situation is more ambiguous for PHIR, in which a pilot study could refer to different purposes. METHODS: The workshop included formal presentations of participants and moderated discussions. An oral synthesis was carried out by a rapporteur to validate by expert consensus the key points of the discussion and the recommendations. All discussions have been recorded and fully transcribed. DISCUSSION: PHIR generally addresses complex interventions. Thus, numerous tasks may be required to inform the intervention and test different aspects of its design and implementation. While in clinical research the pilot study mainly concerns the preparation of the trial, in PHIR the pilot study focuses on the preparation of both the intervention and the trial. In particular, pilot studies in PHIR could be used for viability evaluation and theory development. RECOMMENDATIONS FROM THE WORKSHOP PARTICIPANTS: The following recommendations were generated by consensus from the workshop discussions: i) terms need to be clarified for PHIR; ii) reporting and publication should be standardized and transparency should be promoted; iii) the objectives and research questions should drive the methods used and be clearly stated; iv) a pilot study is generally needed for complex intervention evaluation and for research-designed programs; and v) for field-designed programs, it is important to integrate evaluability assessments as pilot studies . CONCLUSION: Pilot studies play an important role in intervention development and evaluation. In particular, they contribute to a better understanding of the mechanisms of intervention and the conditions of its applicability and transferability. Pilot studies could therefore facilitate evidence-based decisions about design and conduct of main studies aimed to generate evidence to inform public health policy
    • 

    corecore