1,034 research outputs found
Acute Alcohol Consumption, Alcohol Outlets, and Gun Suicide
A case-control study of 149 intentionally self-inflicted gun injury cases (including completed gun suicides) and 302 population-based controls was conducted from 2003 to 2006 in a major US city. Two focal independent variables, acute alcohol consumption and alcohol outlet availability, were measured. Conditional logistic regression was adjusted for confounding variables. Gun suicide risk to individuals in areas of high alcohol outlet availability was less than the gun suicide risk they incurred from acute alcohol consumption, especially to excess. This corroborates prior work but also uncovers new information about the relationships between acute alcohol consumption, alcohol outlets, and gun suicide. Study limitations and implications are discussed
Random Effects Logistic Models for Analyzing Efficacy of a Longitudinal Randomized Treatment With Non-Adherence
We present a random effects logistic approach for estimating the efficacy of treatment for compliers in a randomized trial with treatment non-adherence and longitudinal binary outcomes. We use our approach to analyse a primary care depression intervention trial. The use of a random effects model to estimate efficacy supplements intent-to-treat longitudinal analyses based on random effects logistic models that are commonly used in primary care depression research. Our estimation approach is an extension of Nagelkerke et al.\u27s instrumental variables approximation for cross-sectional binary outcomes. Our approach is easily implementable with standard random effects logistic regression software. We show through a simulation study that our approach provides reasonably accurate inferences for the setting of the depression trial under model assumptions. We also evaluate the sensitivity of our approach to model assumptions for the depression trial
The Identification and Estimation of Direct and Indirect Effects in A/B Tests through Causal Mediation Analysis
E-commerce companies have a number of online products, such as organic
search, sponsored search, and recommendation modules, to fulfill customer
needs. Although each of these products provides a unique opportunity for users
to interact with a portion of the overall inventory, they are all similar
channels for users and compete for limited time and monetary budgets of users.
To optimize users' overall experiences on an E-commerce platform, instead of
understanding and improving different products separately, it is important to
gain insights into the evidence that a change in one product would induce users
to change their behaviors in others, which may be due to the fact that these
products are functionally similar. In this paper, we introduce causal mediation
analysis as a formal statistical tool to reveal the underlying causal
mechanisms. Existing literature provides little guidance on cases where
multiple unmeasured causally-dependent mediators exist, which are common in A/B
tests. We seek a novel approach to identify in those scenarios direct and
indirect effects of the treatment. In the end, we demonstrate the effectiveness
of the proposed method in data from Etsy's real A/B tests and shed lights on
complex relationships between different products.Comment: Accepted by The 25th ACM SIGKDD Conference on Knowledge Discovery and
DataMining (KDD '19), August 4-8, 2019, Anchorage, AK, US
Genetic heterogeneity and trans regulators of gene expression
Heterogeneity poses a challenge to linkage mapping. Here, we apply a latent class extension of Haseman-Elston regression to expression phenotypes with significant evidence of linkage to trans regulators in 14 large pedigrees. We test for linkage, accounting for heterogeneity, and classify individual families as "linked" and "unlinked" on the basis of their contribution to the overall evidence of linkage
Economic inequalities in the effectiveness of a primary care intervention for depression and suicidal ideation.
BACKGROUND: Economic disadvantage is associated with depression and suicide. We sought to determine whether economic disadvantage reduces the effectiveness of depression treatments received in primary care. METHODS: We conducted differential-effects analyses of the Prevention of Suicide in Primary Care Elderly: Collaborative Trial, a primary-care-based randomized, controlled trial for late-life depression and suicidal ideation conducted between 1999 and 2001, which included 514 patients with major depression or clinically significant minor depression. RESULTS: The intervention effect, defined as change in depressive symptoms from baseline, was stronger among persons reporting financial strain at baseline (differential effect size = -4.5 Hamilton Depression Rating Scale points across the study period [95% confidence interval = -8.6 to -0.3]). We found similar evidence for effect modification by neighborhood poverty, although the intervention effect weakened after the initial 4 months of the trial for participants residing in poor neighborhoods. There was no evidence of substantial differences in the effectiveness of the intervention on suicidal ideation and depression remission by economic disadvantage. CONCLUSIONS: Economic conditions moderated the effectiveness of primary-care-based treatment for late-life depression. Financially strained individuals benefited more from the intervention; we speculate this was because of the enhanced treatment management protocol, which led to a greater improvement in the care received by these persons. People living in poor neighborhoods experienced only temporary benefit from the intervention. Thus, multiple aspects of economic disadvantage affect depression treatment outcomes; additional work is needed to understand the underlying mechanisms
The design of a randomised controlled trial to evaluate the (cost-) effectiveness of the posterolateral versus the direct anterior approach for THA (POLADA - trial)
Background: Total hip arthroplasty (THA) is one of the most successful orthopaedic procedures. Because of the increasing number of THAs, a growing demand for faster recovery and a greater emphasis on cost-effectiveness, minimally invasive THAs have been introduced in the last decades. The direct anterior approach is a minimally invasive, tissue-sparing approach in which intermuscular planes are used. Theoretically, this approach should result in a faster recovery of physical functioning and higher health-related quality of life. Methods/design: A randomised controlled trial will be performed. Patients will be randomly allocated to undergo THA by means of the anterior or posterolateral approach. Both the intervention and control group will consist of two subgroups: 1) patients with a good bone stock who will receive an uncemented femoral stem, and 2) patients with a poor bone stock who will receive a cemented femoral stem. Patients between 18 and 90 years with primary or secondary osteoarthritis will be included. Physical functioning and health-related quality of life will be assessed by means of questionnaires. Additionally, performance based tests will be performed to objectively assess the physical functioning. Cost-effectiveness will be assessed by obtaining data on medical costs in and outside the hospital and other nonmedical costs. Measurements will take place preoperatively, two and six weeks, three months and one year postoperatively. Discussion: There is some evidence that the anterior approach results in reduced tissue damage and faster recovery in the direct postoperative period, compared to the posterolateral approach. However, there is still a lack of well-designed studies that have confirmed the better outcomes and cost-effectiveness of the anterior approach. Therefore, the purpose of this study is to assess the physical functioning, health related quality of life and the cost-effectiveness of the anterior approach, compared to the conventional posterolateral approach
Mediation Analysis With Principal Stratification
In assessing the mechanism of treatment efficacy in randomized clinical trials, investigators often perform mediation analyses by analyzing if the significant intent-to-treat treatment effect on outcome occurs through or around a third intermediate or mediating variable: indirect and direct effects, respectively. Standard mediation analyses assume sequential ignorability, i.e. conditional on covariates the intermediate or mediating factor is randomly assigned, as is the treatment in a randomized clinical trial. This research focuses on the application of the principal stratification (PS) approach for estimating the direct effect of a randomized treatment but without the standard sequential ignorability assumption. This approach is used to estimate the direct effect of treatment as a difference between expectations of potential outcomes within latent subgroups of participants for whom the intermediate variable behavior would be constant, regardless of the randomized treatment assignment. Using a Bayesian estimation procedure, we also assess the sensitivity of results based on the PS approach to heterogeneity of the variances among these principal strata. We assess this approach with simulations and apply it to two psychiatric examples. Both examples and the simulations indicated robustness of our findings to the homogeneous variance assumption. However, simulations showed that the magnitude of treatment effects derived under the PS approach were sensitive to model mis-specification
‘What’s it like to have ME?’ The discursive construction of ME in computer-mediated communication and face-to-face interaction
ME/CFS (chronic fatigue syndrome) is a debilitating illness for which no cause or medical tests have been identified. Debates over its nature have generated interest from qualitative researchers. However, participants are difficult to recruit because of the nature of their condition. Therefore, this study explores the utility of the internet as a means of eliciting accounts. We analyse data from focus groups and the internet in order to ascertain the extent to which previous research findings apply to the internet domain. Interviews were conducted among 49 members of internet (38 chatline, 11 personal) and 7 members of two face-to-face support groups. Discourse analysis of descriptions and accounts of ME/CFS revealed similar devices and interactional concerns in both internet and face-to-face communication. Participants constructed their condition as serious, enigmatic and not psychological. These functioned to deflect problematic assumptions about ME/CFS and to manage their accountability for the illness and its effects
Effect of dietary interventions on markers of type 2 inflammation in asthma:A systematic review
INTRODUCTION: Type 2 (T2) inflammation is a key mechanism in the pathophysiology of asthma. Diet may have immunomodulatory effects, and a role for diet in T2 inflammation has been suggested in the literature. Indeed, diet and food allergies play a role in children with atopic asthma, but less is known about diet in relation to adult asthma, which is often non-atopic.OBJECTIVE: To review the effect of dietary interventions on markers of T2 inflammation in adults with asthma.METHODS: The databases PubMed, Embase, Cochrane Library, and CINAHL were searched for eligible studies until December 2022. We included studies of all types of foods, nutrients, diets or supplements, either as an exposure or as an intervention, in adults and adolescents with asthma. Outcomes of interest included the T2 biomarkers FeNO, eosinophils, IL-4, IL-5, IL-13, eosinophil cationic protein and eosinophil peroxidase. The methodological quality of eligible studies was systematically evaluated, and the results were summarised according to dietary clusters.RESULTS: The systematic search identified studies on the dietary clusters antioxidants (n = 14), fatty acids, (n = 14), Mediterranean-style diets (n = 5), phytotherapy (n = 7), prebiotics & probiotics (n = 8), vitamin D (n = 7), and other dietary factors (n = 5). Studies within the phytotherapy and omega-3 poly-unsaturated fatty acids (PUFA) clusters showed possible improvements in T2 inflammation. Furthermore, we found little evidence for an effect of antioxidants, prebiotics & probiotics, and Mediterranean-style diets on T2 inflammation. However, heterogeneity in study protocols, methodological shortcomings and limited power of almost all studies make it difficult to fully determine the impact of different dietary approaches on T2 inflammation in asthma.CONCLUSIONS: Overall, the current evidence does not support a specific dietary intervention to improve T2 inflammation in asthma. Interventions involving phytotherapy and omega-3 PUFA currently have the best evidence and warrant further evaluation in well-designed and adequately powered studies, while taking into account T2-high phenotypes of asthma.</p
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