A primer on the use of cluster analysis or factor analysis to assess co-occurrence of risk behaviors

Objective: The aim of this paper is to provide a guideline to a universal understanding of the analysis of co-occurrence of risk behaviors. The use of cluster analysis and factor analysis was clarified. Method: A theoretical introduction to cluster analysis and factor analysis and examples from literature were provided. A representative sample ...

Overlap of cognitive concepts in chronic widespread pain: An exploratory study

Background: A wide variety of cognitive concepts have been shown to play an important role in chronic widespread pain (CWP). Although these concepts are generally considered to be distinct entities, some might in fact be highly overlapping. The objectives of this study were to (i) to establish inter-relationships between self-efficacy, cognitive...

Self-report form of the Child Health Questionnaire in a Dutch adolescent population

The Child Health Questionnaire (CHQ)-87-item child and adolescent self-report (CF87) is an increasingly used health-related quality-of-life instrument for measuring the self-perceived physical and psychosocial well-being of children aged 10 years and older. The aims of this study were to evaluate structure, reliability and validity of the Dutch...

Testing the structural and cross-cultural validity of the KIDSCREEN-27 quality of life questionnaire

Objectives: The aim of this study is to assess the structural and cross-cultural validity of the KIDSCREEN-27 questionnaire. Methods: The 27-item version of the KIDSCREEN instrument was derived from a longer 52-item version and was administered to young people aged 8-18 years in 13 European countries in a cross-sectional survey. Structural and...

Characteristics of peaks of inhalation exposure to organic solvents

Objectives: To determine which exposure metrics are sufficient to characterize 'peak' inhalation exposure to organic solvents (OS) during spraying operations. Methods: Personal exposure measurements (n = 27; duration 5-159 min) were collected during application of paints, primers, resins and glues in 15 companies. A MiniRAE Photolonization...

Extended histopathology in immunotoxicity testing: Interlaboratory validation studies

There has been considerable interest in the use of expanded histopathology as a primary screen for immunotoxicity assessment. To determine the utility of a semiquantitative histopathology approach for examining specific structural and architectural changes in lymphoid tissues, a validation effort was initiated. This study addresses the...

Dietary patterns associated with colon and rectal cancer: Results from the Dietary Patterns and Cancer (DIETSCAN) Project

Background: An analysis of dietary patterns or combinations of foods may provide insight regarding the influence of diet on the risk of colon and rectal cancer. Objective: A primary aim of the Dietary Patterns and Cancer (DIETSCAN) Project was to develop and apply a common methodologic approach to study dietary patterns and cancer in 4 European...

The Depression Anxiety Stress Scales (DASS): Detecting anxiety disorder and depression in employees absent from work because of mental health problems

Aims: To (1) evaluate the psychometric properties and (2) examine the ability to detect cases with anxiety disorder and depression in a population of employees absent from work because of mental health problems. Methods: Internal consistency, construct validity, and criterion validity of the Depression Anxiety Stress Scales (DASS) were assessed....

Polytomous Rasch analysis as a tool for revision of the severity of disability code of the ICIDH

Purpose: To develop a preliminary proposal for the revision of the severity code of the ICIDH-D 1980. Method: Quantitative analysis (polytomous Rasch analysis) of linked existing data sources including items about walking and dressing disability. Results: The Rasch analysis provided estimates of threshold parameters for walking and dressing item...

Statistically designed experiments to screen chemical mixtures for possible interactions

For the accurate analysis of possible interactive effects of chemicals in a defined mixture, statistical designs are necessary to develop clear and manageable experiments. For instance, factorial designs have been successfully used to detect two-factor interactions. Particularly useful for this purpose are fractionated factorial designs,...

Subacute toxicity of a mixture of nine chemicals in rats: Detecting interactive effects with a fractionated two-level factorial design

The present study was intended (1) to find out whether simultaneous administration of nine chemicals at a concentration equal to the 'no-observed-adverse-effect level' (NOAEL) for each of them would result in a NOAEL for the combination and (2) to test the usefulness of fractionated factorial models to detect possible interactions between...

Use of factorial designs in combination toxicity studies

The use of factorial designs, in which n chemicals are studied at x(n) dose levels (x treatment groups), has been put forward as one of the valuable statistical approaches for hazard assessment of chemical mixtures. Very recently a '25 study' was presented to describe interactions between the carcinogenic activity of five polycyclic aromatic...

Psychosocial stressors at work and musculoskeletal problems

Objectives - This paper examines the relationship between work stressors and the following health indicators: psychosomatic complaints, health behavior, and musculoskeletal problems. Methods - Secondary analyses were performed on data from the National Work and Living Condition Survey, which provides a representative sample of the working...