The Danish Physical Activity Cohort with Objective measurements: cohort profile

Background.
Current available research on the association between physical work demandsand musculoskeletal pain has been criticized for using self-reported data, crosssectionaldesign, insufficient adjustment for potential confounders and inadequate followup on the recurrent and fluctuating pattern of musculoskeletal pain. In this abstract, wereport on the profile of the Danish Physical Activity Cohort with Objective Measurements(DPhacto). DPhacto investigated the association between objective diurnal field measurementsof physical activities and provides follow up on pain.
Methods.
Eligible workers (n=2,107) from 15 Danish companies within the cleaning,transportation and manufacturing sectors were invited to participate in the study. Workersresponded to a baseline questionnaire and participated in physical tests. They alsowore accelerometers and heart rate monitors for four consecutive days. Finally, workersresponded to monthly text messages regarding pain and quarterly questionnaires concerningthe consequences of pain on work activities, social activities and work ability for aone-year, follow-up period.Results. 1,087 (52%) workers participated – 901 from blue-collar occupations and 185from white-collar occupations. Analyses of the representativeness of the study populationindicated that it was representative of the background target population, exceptthat women were slightly more likely to consent to participate. Objective measurementdevices were mounted on 909 workers in total and response rate to the monthly text messages was >80%. Almost all (99%) participants provided their social security number, which offers a unique opportunity for longitudinal register-based follow up.
Discussion.
Opportunities for high quality, prospective analyses on the association between physical activities at work and leisure that account for health and work-related outcomes are enabled by a number of factors. These include: successful recruitment of participants; good follow-up rates; and, large variance in types and amounts of physical activities during work and leisure within the measured population.