The Linkset Model for 2^n Contingency Tables

Abstract The linkset model is defined for parametrizing the general 2^n contingency table. The linkset parameters are designed to represent latent influences that promote the co-occurrences of binary events beyond that explained by chance. Linkages involving 2 through n binary variables are included in this parametrization. The intent of this process is to elucidate the patterns of linkage, no matter how complex they might be, rather than to fit simplifying models. The relationship between linkset parameters and the natural parameters for a 2n table are derived, and large sample inference methods are provided. Examples are given from medical diagnostics, survival from the Titanic sinking, and employment discrimination in Chicago

Augmentation of Propensity Scores for Medical Records-based Research

Therapeutic research based on electronic medical records suffers from the possibility of various kinds of confounding. Over the past 30 years, propensity scores have increasingly been used to try to reduce this possibility. In this article a gap is identified in the propensity score methodology, and it is proposed to augment traditional treatment-propensity scores with outcome-propensity scores, thereby removing all other aspects of common causes from the analysis of treatment effects

Recovery of the Baseline Incidence Density in Censored Time-to-Event Analysis

Abstract Time-to-event analyses are often concerned with the effects of explanatory factors on the underlying incidence density, but since there is no intrinsic interest in the form of the incidence density itself, a proportional hazards model is used. When part of the purpose of the analysis is to use actual cumulative incidence for simulation, or for providing informative visual displays of the results, an estimate of the baseline incidence density is required. The usual method for estimating the baseline hazards in Cox’s proportional hazards analysis yields values that are of little use, and furthermore no standard deviations of the estimates (SDEs) are available. In this article we present an alternative approach to recovering an estimate of the baseline incidence density that yields smooth estimates as well as smooth estimates of SDEs. We illustrate the method on a large dataset of inter-visit times for individuals in a diabetes registry, and indicate how it can be used to incorporate different baseline incidence densities in the analysis of different subgroups. Keywords: proportional hazards, exponential regression, survival analysis, diabete

Reduction of Murine Cutaneous UVB-Induced Tumor-Infiltrating T Lymphocytes by Dietary Canthaxanthin

The effect of dietary canthaxanthin, retinyl palmitate, or their combination on the tumor-infiltrating T-lymphocyte response (T-TIL) in de novo murine ultraviolet type B irradiation-induced tumors was investigated to elucidate potential mechanisms of action of these compounds. We found that dietary canthaxanthin greatly reduced the number of tumor-infiltrating helper/inducer, suppressor/cytotoxic, and interleukin-2 receptor-positive T lymphocytes and also observed a concomitant statistically significant increase in tumour incidence in canthaxanthin-fed animals. The addition of retinyl palmitate to the canthaxanthin diet ameliorated this negative effect on TIL and the development of skin tumors. We conclude that dietary retinyl palmitate and canthaxanthin can modulate the host T-cell immune response within a growing tumor and may affect tumorigenicity

Randomized Controlled Trials of Acupuncture (1997–2007): An Assessment of Reporting Quality with a CONSORT- and STRICTA-Based Instrument

The present study describes the development of a comprehensive quality of reporting assessment tool and its application to acupuncture RCTs from 1997–2007. This Oregon CONSORT STRICTA Instrument (OCSI) is based on the revised CONSORT guidelines as modified by the STRICTA recommendations for acupuncture trials. Each of the resulting 27 OCSI items were applied to English language prospective RCTs that compared acupuncture, using manual and/or electro-stimulation, to no treatment, a sham procedure, or usual biomedical care. The 333 RCTs that met inclusion criteria were dispersed among 27 countries and 141 journals. Mean quality of reporting score for all articles was 63.0% (SD 16.5). Mean OCSI scores revealed a 30.9% improvement over the ten-year period (P < .001). Our findings suggest that to enhance quality of reporting, authors should better attend to seven specific OCSI items in three categories: practitioner training, adverse events, and aspects of randomization and blinding (n = 5). The broad diversity in geographical origin, publication site and quality of reporting, viewed in light of the considerable room for improvement in mean OCSI scores, emphasizes the importance of making STRICTA as well as CONSORT more widely known to journals and to the acupuncture research community

Hip bone density predicts breast cancer risk independently of Gail score: Results From the Women's Health Initiative

The Gail model has been commonly used to estimate a woman’s breast cancer risk in a certain time period. High bone mineral density (BMD) is also a significant risk factor for breast cancer, but it plays no role in the Gail model. The objective of this study was to investigate whether hip BMD predicts postmenopausal breast cancer risk independently of the Gail score

A Community-Based Intervention to Prevent Obesity Beginning at Birth among American Indian Children: Study Design and Rationale for the PTOTS study

Eating and physical activity behaviors associated with adult obesity have early antecedents, yet few studies have focused on obesity prevention interventions targeting very young children. Efforts to prevent obesity beginning at birth seem particularly important in populations at risk for early-onset obesity. National estimates indicate that American Indian (AI) children have higher rates of overweight and obesity than children of other races/ethnicities. The Prevention of Toddler Obesity and Teeth Health Study (PTOTS) is a community-partnered randomized controlled trial designed to prevent obesity beginning at birth in AI children. PTOTS was developed to test the effectiveness of a multi-component intervention designed to: promote breastfeeding, reduce sugar-sweetened beverage consumption, appropriately time the introduction of healthy solid foods, and counsel parents to reduce sedentary lifestyles in their children. A birth cohort of 577 children from five AI tribes is randomized by tribe to either the intervention (three tribes) or the comparison condition (two tribes). The strengths and weaknesses of PTOTS include a focus on a critical growth phase, placement in the community, and intervention at many levels, using a variety of approaches

Effectiveness guidance document (EGD) for acupuncture research - a consensus document for conducting trials

Abstract Background There is a need for more Comparative Effectiveness Research (CER) to strengthen the evidence base for clinical and policy decision-making. Effectiveness Guidance Documents (EGD) are targeted to clinical researchers. The aim of this EGD is to provide specific recommendations for the design of prospective acupuncture studies to support optimal use of resources for generating evidence that will inform stakeholder decision-making. Methods Document development based on multiple systematic consensus procedures (written Delphi rounds, interactive consensus workshop, international expert review). To balance aspects of internal and external validity, multiple stakeholders including patients, clinicians and payers were involved. Results Recommendations focused mainly on randomized studies and were developed for the following areas: overall research strategy, treatment protocol, expertise and setting, outcomes, study design and statistical analyses, economic evaluation, and publication. Conclusion The present EGD, based on an international consensus developed with multiple stakeholder involvement, provides the first systematic methodological guidance for future CER on acupuncture.http://deepblue.lib.umich.edu/bitstream/2027.42/112870/1/12906_2012_Article_1127.pd