title: Concurrent and predictive validity of physical activity measurement items commonly used in clinical settings--data from SCAPIS pilot study.
abstract: BACKGROUND
  As the understanding of how different aspects of the physical activity (PA) pattern relate to health and disease, proper assessment is increasingly important. In clinical care, self-reports are the most commonly used assessment technique. However, systematic comparisons between questions regarding concurrent or criterion validity are rare, as are measures of predictive validity. The aim of the study was to examine the concurrent (using accelerometry as reference) and predictive validity (for metabolic syndrome) of five PA questions.
  
  
  METHODS
  A sample of 948 middle-aged Swedish men and women reported their PA patterns via five different questions and wore an accelerometer (Actigraph GT3X) for a minimum of 4 days. Concurrent validity was assessed as correlations and ROC-analyses. Predictive validity was assessed using logistic regression, controlling for potential confounders.
  
  
  RESULTS
  Concurrent validity was low-to-moderate (r <0.35 and ROC AUC <0.7) with large misclassifications regarding time spent sitting/sedentary and in moderate-to vigorous PA. The predictive validity of the questions was good, and one question (PHAS) showed an 80 % decreased odds-ratio of having metabolic syndrome, after taking potential confounders into consideration.
  
  
  CONCLUSIONS
  In this mixed sample of adults, both concurrent and predictive validity vaired between items and between measures of the physical activity pattern. The PHAS and WALK items are proposed for assessment of adherence to PA recommendations.
  
  
  CONCLUSIONS
  Assessing PA patterns using self-report measures results in methodological problems when trying to predict individual risk for the metabolic syndrome, as the concurrent validity generally was low. However, several of the investigated questions may be useful for assessing risk at a group level, showing better predictive validity.
authors.affiliation: Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, Stockholm, Sweden. orjan.ekblom@gih.se.
authors.forename: Örjan
authors.initials: Ö
authors.lastname: Ekblom
authors.affiliation: Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, Stockholm, Sweden. eline@gih.se.
authors.forename: Elin
authors.initials: E
authors.lastname: Ekblom-Bak
authors.affiliation: Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, Stockholm, Sweden. kate.bolam@gih.se.|School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia. kate.bolam@gih.se.
authors.forename: Kate A
authors.initials: KA
authors.lastname: Bolam
authors.affiliation: Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, Stockholm, Sweden. bjorn.ekblom@gih.se.
authors.forename: Björn
authors.initials: B
authors.lastname: Ekblom
authors.affiliation: Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden. Caroline.Schmidt@wlab.gu.se.|Sahlgrenska Centre for Cardiovascular and Metabolic Research, Wallenberg Laboratory, Sahlgrenska University Hospital, Gothenburg, Sweden. Caroline.Schmidt@wlab.gu.se.
authors.forename: Caroline
authors.initials: C
authors.lastname: Schmidt
authors.affiliation: Department of Public Health and Clinical Medicine, Medicine and Heart Centre, Umeå University, Umeå, Sweden. stefan.soderberg@medicin.umu.se.
authors.forename: Stefan
authors.initials: S
authors.lastname: Söderberg
authors.affiliation: Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden. Goran.Bergstrom@hjl.gu.se.|Sahlgrenska Centre for Cardiovascular and Metabolic Research, Wallenberg Laboratory, Sahlgrenska University Hospital, Gothenburg, Sweden. Goran.Bergstrom@hjl.gu.se.
authors.forename: Göran
authors.initials: G
authors.lastname: Bergström
authors.affiliation: Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, Stockholm, Sweden. mats.brjesson@telia.com.|Karolinska University Hospital, Stockholm, Sweden. mats.brjesson@telia.com.
authors.forename: Mats
authors.initials: M
authors.lastname: Börjesson
mesh_terms: D061725:Accelerometry; D001837:Body Weights and Measures; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology*; D008875:Middle Aged; D016017:Odds Ratio; D010865:Pilot Projects; D012372:ROC Curve; D015203:Reproducibility of Results; D012306:Risk; D057185:Sedentary Behavior; D057566:Self Report / Q000592:standards*; D012959:Socioeconomic Factors; D013997:Time Factors