Associations between polymorphisms in leptin and leptin receptor genes and colorectal cancer survival.

Objective: Leptin (LEP) is an obesity-associated adipokine associated with tumor cell growth. We examined the relevance of genetic variants of and leptin receptor () to colorectal cancer (CRC) survival by using data from the Newfoundland Familial Colorectal Cancer Study.

Methods: A total of 532 patients newly diagnosed with CRC between 1997 and 2003 were followed up until April 2010.

The Roles of and Gene Polymorphisms in Colorectal Cancer Survival.

Background: Paradoxically epidemiological data illustrate a negative relationship between dietary folate intake and colorectal cancer (CRC) risk. The occurrence and progression of CRC may be influenced by variants in some key enzyme coding genes in the folate metabolic pathway. We investigated the correlation between genetic variants in methionine synthase reductase () and methylenetetrahydrofolate reductase () and CRC survival.

Association between Dietary Fiber Intake and Mortality among Colorectal Cancer Survivors: Results from the Newfoundland Familial Colorectal Cancer Cohort Study and a Meta-Analysis of Prospective Studies.

We examined dietary fiber intake for its relevance to Colorectal cancer (CRC) survival in a cohort of CRC patients and a meta-analysis including results from four prospective cohort studies. We analyzed 504 CRC patients enrolled in the Newfoundland Familial Colorectal Cancer Study (NFCCS) who were newly diagnosed with CRC between 1999 and 2003. Follow-up for deaths was through April 2010.

Risk Stratification for Early-Onset Colorectal Cancer Using a Combination of Genetic and Environmental Risk Scores: An International Multi-Center Study.

Background: The incidence of colorectal cancer (CRC) among individuals aged younger than 50 years has been increasing. As screening guidelines lower the recommended age of screening initiation, concerns including the burden on screening capacity and costs have been recognized, suggesting that an individualized approach may be warranted. We developed risk prediction models for early-onset CRC that incorporate an environmental risk score (ERS), including 16 lifestyle and environmental factors, and a polygenic risk score (PRS) of 141 variants.

Variation and appropriateness of antipsychotic use in long-term care facilities across Newfoundland and Labrador.

Objective: The use of antipsychotics to treat seniors in long-term care facilities (LTCFs) has raised concern because of health consequences (i.e., increased risk of falls, stroke, death) in this vulnerable population.

Nongenetic Determinants of Risk for Early-Onset Colorectal Cancer.

Background: Incidence of early-onset (younger than 50 years of age) colorectal cancer (CRC) is increasing in many countries. Thus, elucidating the role of traditional CRC risk factors in early-onset CRC is a high priority. We sought to determine whether risk factors associated with late-onset CRC were also linked to early-onset CRC and whether association patterns differed by anatomic subsite.

Changing Health-Related Behaviors 4: Realizing Impact of Health Research Through Knowledge Translation.

Knowledge translation (KT) is critical to realizing real-world impacts from health research by reducing the amount of time it takes for evidence to inform practice. One way this is achieved is by engaging with knowledge users throughout the process to ensure that research responds to their needs. It is also important to share the study results in a way that is useful, accessible, and relevant to knowledge user groups.

Changing Health-Related Behaviors 2: On Improving the Value of Health Spending.

The quantity of health spending does not equate directly to the quality of healthcare. Social spending and nonmedical determinants of health impact on health outcomes. The value of health spending in the United States is limited by the high cost of goods and labor, and administrative costs, high use of low-level care, and lack of basic healthcare coverage in a substantial minority of the population.

Randomized Controlled Trials 7: On Contamination and Estimating the Actual Treatment Effect.

The intention-to-treat analysis is the gold standard for evaluating the efficacy in a randomized controlled trial. However, when non-adherence to randomized treatments is high the actual treatment effect may be underestimated. The impact of drop-out from the intervention group or drop-in to the control group may be controlled by trial design, increasing the sample size, effective study execution, and a pre-specified analytical plan to take contamination into account.

Randomized Controlled Trials 4: Planning, Analysis, and Interpretation of Quality-of-Life Studies.

Quality-of-life (QoL) outcomes are important elements of randomized controlled trials. The instruments for measurement of QoL vary but usually multiple comparisons are possible, a concern that can be offset by prespecifying the outcomes of interest. Missing data may threaten the validity of QoL assessments in trials.

Randomized Controlled Trials 2: Analysis.

When analyzing the results of a trial, the primary outcome variable must be kept in clear focus. In the analysis plan, consideration must be given to comparing the characteristics of the subjects, taking account of differences in these characteristics, intention-to-treat analysis, interim analyses and stopping rules, mortality comparisons, composite outcomes, research design including run-in periods, factorial, stratified and crossover designs, number needed to treat, power issues, multivariate modeling, subgroup analysis, competing risks, and hypothesis-generating analyses.

Randomized Controlled Trials 1: Design.

Today's clinical practice relies on the application of well-designed clinical research, the gold standard test of an intervention being the randomized controlled trial. Principles of the randomized control trial include emphasis on the principal research question, randomization, blinding; definitions of outcome measures, of inclusion and exclusion criteria, and of co-morbid and confounding factors; enrolling an adequate sample size; planning data management and analysis; preventing challenges to trial integrity such as drop-out, drop-in, and bias. The application of pre-trial planning is stressed to ensure the proper application of epidemiological principles resulting in clinical studies that are feasible and generalizable.

Longitudinal Studies 3: Data Modeling Using Standard Regression Models and Extensions.

In longitudinal studies, the relationship between exposure and disease can be measured once or multiple times while participants are monitored over time. Traditional regression techniques are used to model outcome data when each epidemiological unit is observed once. These models include generalized linear models for quantitative continuous, discrete, or qualitative outcome responses, and models for time-to-event data.

Longitudinal Studies 2: Modeling Data Using Multivariate Analysis.

Statistical models are used to study the relationship between exposure and disease while accounting for the potential role of other factors' impact upon outcomes. This adjustment is useful to obtain unbiased estimates of true effects or to predict future outcomes. Statistical models include a systematic and an error component.

Bias in Clinical Research.

Clinical epidemiological research entails assessing the burden and etiology of disease, the diagnosis and prognosis of disease, the efficacy of preventive measures or treatments, the analysis of the risks and benefits of diagnostic and therapeutic maneuvers, and the evaluation of health care services. In all areas, the main focus is to describe the relationship between exposure and outcome and to determine one of the following: prevalence, incidence, cause, prognosis, or effect of treatment. The accuracy of these conclusions is determined by the validity of the study.

On Framing the Research Question and Choosing the Appropriate Research Design.

Clinical epidemiology is the science of human disease investigation with a focus on diagnosis, prognosis, and treatment. The generation of a reasonable question requires definition of patients, interventions, controls, and outcomes. The goal of research design is to minimize error, ensure adequate samples, measure input and output variables appropriately, consider external and internal validities, limit bias, and address clinical as well as statistical relevance.