The Canadian STOP-PAIN project: the burden of chronic pain-does sex really matter?

Objectives: The Canadian STOP-PAIN Project assessed the human and economic burden of chronic pain (CP) in individuals on waitlists of Canadian multidisciplinary pain treatment facilities. This article focuses on sex differences. Objectives were to (1) determine the pain characteristics and related biopsychosocial factors that best differentiated women and men with CP; and (2) examine whether public and private costs associated with CP differed according to sex.

Different models and single-nucleotide polymorphisms signal the simulated weak gene-gene interaction for a quantitative trait using haplotype-based and mixed models testing.

Knowledge of simulated genetic effects facilitates interpretation of methodological studies. Genetic interactions for common disorders are likely numerous and weak. Using the 200 replicates of the Genetic Analysis Workshop 16 (GAW16) Problem 3 simulated data, we compared the statistical power to detect weak gene-gene interactions using a haplotype-based test in the UNPHASED software with genotypic mixed model (GMM) and additive mixed model (AMM) mixed linear regression model in SAS.

Two-stage strategies to detect gene x gene interactions in case-control data.

Large genetic association studies based on hundreds of thousands of single-nucleotide polymorphisms (SNPs) are a popular option for the study of complex diseases. The evaluation of gene x gene interactions in such studies is a sensible method of capturing important genetic effects. The number of tests required to consider all pairs of SNPs, however, can lead to a computational burden, and efficient strategies to reduce the number of tests performed are desirable.

Multistage designs in the genomic era: providing balance in complex disease studies.

In this summary paper, we describe the contributions included in the Multistage Design group (Group 14) at the Genetic Analysis Workshop 15, which was held during November 12-14, 2006. Our group contrasted and compared different approaches to reducing complexity in a genetic study through implementation of staged designs. Most groups used the simulated dataset (problem 3), which provided ample opportunities for evaluating various staged designs.

Noninvasive evaluation of endothelial vascular reactivity: should the quest continue?

Endothelial dysfunction is an early event in the continuum of the pathogenesis of atherosclerosis that persists throughout the disease process. Endothelial dysfunction may be a valuable marker or barometer of the composite effect of the various predisposing factors, even some yet unknown, on the subsequent risk of cardiovascular events. Accumulating data suggest that clinical evaluation of endothelial function may provide incremental value to current risk stratification and to the tailoring of pharmacological and nonpharmacological therapy.