221 research outputs found
Is the biology of breast cancer changing? A study of hormone receptor status 1984-1986 and 1996-1997
Using archived tumours, those from 1984-1986 and 1996-1997 underwent immunohistochemistry for hormone receptors and grade analysis. A significant shift towards more ER-positive and low-grade disease was found; this appears to reflect screening practices, but could still influence survival
International Comparative Studies In Mathematics: Lessons For Improving students’ Learning
Comparing is one of the most basic intellectual activities. We consciously make comparisons to understand where we stand, both in relation to others as well as to our own past experiences. There has been a long history of international comparative studies in education (Alexander 2000). Especially in the past several decades, many international comparative studies of mathematics have been conducted, either to examine differences in mathematical proficiency and dispositions among students from various countries or to understand the possible influence on the observed differences of various factors such as curriculum, teacher preparation, quality of classroom instruction, and parental involvement. Some of these studies are large-scale, and others are small-scale in-depth analyses from cognitive or social perspectives. These international comparative studies in mathematics are valuable because they provide a large body of knowledge showing how students do mathematics in the context of the world’s varied educational institutions. In addition, they examine the cultural and educational factors that influence the learning of mathematics.published_or_final_versio
Circulating levels of dickkopf-1, osteoprotegerin and sclerostin are higher in old compared with young men and women and positively associated with whole-body bone mineral density in older adults
Summary: Bone mineral density declines with increasing older age. We examined the levels of circulating factors known to regulate bone metabolism in healthy young and older adults. The circulating levels of dickkopf-1, osteocalcin, osteoprotegerin and sclerostin were positively associated with WBMD in older adults, despite the average WBMD being lower and circulating dickkopf-1, osteoprotegerin and sclerostin being higher in old than young.
Purpose: To investigate the relationship between whole-body bone mineral density (WBMD) and levels of circulating factors with known roles in bone remodelling during 'healthy' ageing.
Methods: WBMD and fasting plasma concentrations of dickkopf-1, fibroblast growth factor-23, osteocalcin, osteoprotegerin, osteopontin and sclerostin were measured in 272 older subjects (69 to 81 years; 52% female) and 171 younger subjects (18-30 years; 53% female).
Results: WBMD was lower in old than young. Circulating osteocalcin was lower in old compared with young, while dickkopf-1, osteoprotegerin and sclerostin were higher in old compared with young. These circulating factors were each positively associated with WBMD in the older adults and the relationships remained after adjustment for covariates (r-values ranging from 0.174 to 0.254, all p<0.01). In multivariate regression, the body mass index, circulating sclerostin and whole-body lean mass together accounted for 13.8% of the variation with WBMD in the older adults. In young adults, dickkopf-1 and body mass index together accounted for 7.7% of variation in WBMD.
Conclusion: Circulating levels of dickkopf-1, osteocalcin, osteoprotegerin and sclerostin are positively associated with WBMD in community-dwelling older adults, despite the average WBMD being lower and circulating dickkopf-1, osteoprotegerin and sclerostin being higher in old than young
Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event
addresses: Peninsula College of Medicine and Dentistry, St Luke's Campus, University of Exeter, Exeter, UK. [email protected]: PMCID: PMC3528446types: Journal Article; Research Support, Non-U.S. Gov't© 2012 Warren et al.; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention
Happiness Through Vacationing: Just a Temporary Boost or Long-Term Benefits?
Does vacationing add to our happiness in the long run? This question was addressed in a study of 3,650 Dutch citizens who reported their leisure travel every 3 months during 2 years and rated their happiness at the end of each year. Participants who had been on vacation appeared to be marginally happier, in terms of hedonic level of affect, than those who had not. This difference in Affect balance between vacationers and non-vacationers is probably due to a very minor causal effect of vacationing on hedonic level of affect. Possibly, vacationing is positively reminisced and these memories allow for the prevalence of more positive affect in people's lives. Happiness did not predict vacationing. The effect of holiday trips on vacationers' happiness is mostly short-lived; among vacationers, happiness was unrelated to the number of trips and days spent on vacation. A separate analysis of vacationers, who value vacationing most, yielded the same results. Implications for future research are discussed
Is there a subjective well-being premium in voluntary sector employment?
Previous studies have found that employment in the voluntary sector offers a so-called ‘job satisfaction premium’: despite lower salaries, voluntary sector employees are more satisfied with their jobs than workers in other sectors. This paper examines whether voluntary sector employees also experience a subjective well-being premium. Using data from the UK Annual Population Survey 2012/2013, we find that voluntary sector employees do have higher levels of subjective well-being but this subjective well-being premium is not evenly distributed between men and women. Men score higher on happiness and life satisfaction. However, women in the voluntary sector have lower levels of life satisfaction compared with their counterparts in the public sector. We discuss the implications of our findings for policy and practice in the voluntary sector in the UK
Barriers and enablers to recruiting participants within paediatric perioperative and anaesthetic settings: lessons learned from a trial of melatonin versus midazolam in the premedication of anxious children (the MAGIC trial)
\ua9 2025 The Author(s)Background: Poor recruitment is one key reason for premature closure of randomised controlled trials. The Melatonin for Anxiety prior to General Anaesthesia In Children (MAGIC) trial was a multicentre randomised controlled trial of melatonin vs midazolam in the premedication of anxious children, before surgery. The trial ran between 2019 and 2022, closing early because of recruitment futility. This paper describes the challenges that arose during the trial and offers recommendations for the design of future perioperative trials. Methods: A case-based approach was used to identify barriers to recruitment. As part of a qualitative sub-study, semi-structured interviews with local site teams, participants, and caregivers also explored barriers and enablers to recruitment. Results: Issues encountered included time sensitivity within pressured environments; feasibility of paediatric assent; research pharmacy availability; variation in anaesthetist equipoise; multifactorial decision-making issues in premedication selection; and the Associate Principal Investigator scheme being unable to support trials within anaesthetic trainee rotations. Future paediatric perioperative medicine trials could consider funding for research pharmacy outside of working hours; conducting risk assessments for study drugs to be held on theatre admission units; and a tailored design of site feasibility assessments to help address variation in practice. Challenges remain for the feasibility of including anaesthetic trainees within the Associate Principal Investigator scheme structure. Conclusions: There are significant challenges to recruitment for paediatric clinical trials in anaesthesia and perioperative medicine. The MAGIC trial highlighted variations within anaesthetic practice at individual, local, and regional levels. Lessons learned from the MAGIC trial identifies specific barriers to paediatric trial enrolment, offer solutions and discusses ongoing challenges. Clinical trial registration: ISRCTN registry: ISRCTN18296119
Inclusion of zero total event trials in meta-analyses maintains analytic consistency and incorporates all available data
BACKGROUND: Meta-analysis handles randomized trials with no outcome events in both treatment and control arms inconsistently, including them when risk difference (RD) is the effect measure but excluding them when relative risk (RR) or odds ratio (OR) are used. This study examined the influence of such trials on pooled treatment effects. METHODS: Analysis with and without zero total event trials of three illustrative published meta-analyses with a range of proportions of zero total event trials, treatment effects, and heterogeneity using inverse variance weighting and random effects that incorporates between-study heterogeneity. RESULTS: Including zero total event trials in meta-analyses moves the pooled estimate of treatment effect closer to nil, decreases its confidence interval and decreases between-study heterogeneity. For RR and OR, inclusion of such trials causes small changes, even when they comprise the large majority of included trials. For RD, the changes are more substantial, and in extreme cases can eliminate a statistically significant effect estimate. CONCLUSION: To include all relevant data regardless of effect measure chosen, reviewers should also include zero total event trials when calculating pooled estimates using OR and RR
Variables with time-varying effects and the Cox model: Some statistical concepts illustrated with a prognostic factor study in breast cancer
International audienceBACKGROUND: The Cox model relies on the proportional hazards (PH) assumption, implying that the factors investigated have a constant impact on the hazard - or risk - over time. We emphasize the importance of this assumption and the misleading conclusions that can be inferred if it is violated; this is particularly essential in the presence of long follow-ups. METHODS: We illustrate our discussion by analyzing prognostic factors of metastases in 979 women treated for breast cancer with surgery. Age, tumour size and grade, lymph node involvement, peritumoral vascular invasion (PVI), status of hormone receptors (HRec), Her2, and Mib1 were considered. RESULTS: Median follow-up was 14 years; 264 women developed metastases. The conventional Cox model suggested that all factors but HRec, Her2, and Mib1 status were strong prognostic factors of metastases. Additional tests indicated that the PH assumption was not satisfied for some variables of the model. Tumour grade had a significant time-varying effect, but although its effect diminished over time, it remained strong. Interestingly, while the conventional Cox model did not show any significant effect of the HRec status, tests provided strong evidence that this variable had a non-constant effect over time. Negative HRec status increased the risk of metastases early but became protective thereafter. This reversal of effect may explain non-significant hazard ratios provided by previous conventional Cox analyses in studies with long follow-ups. CONCLUSIONS: Investigating time-varying effects should be an integral part of Cox survival analyses. Detecting and accounting for time-varying effects provide insights on some specific time patterns, and on valuable biological information that could be missed otherwise
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