A Wide Range of Activity Duration Cutoffs Provided Unbiased Estimates of Exposure to Computer Use

Details

• Personal Author:
  Chang CH ; Dennerlein, Jack T. ; Johnson PW ; Chang CH ; Dennerlein, Jack T. ; Johnson PW
• Description:
  Integrative computer usage monitors have become widely used in epidemiologic studies to investigate the exposure-response relationship of computer-related musculoskeletal disorders. These software programs typically estimate the exposure duration of computer use by summing precisely recorded durations of input device activities and durations of inactivity periods shorter than a predetermined activity duration cutoff value, usually 30 or 60 sec. The goal of this study was to systematically compare the validity of a wide range of cutoff values. Computer use activity of 20 office workers was observed for 4 consecutive hours using both a video camera and a usage monitor. Video recordings from the camera were analyzed using specific observational criteria to determine computer use duration. This observed duration then served as the reference and was compared with 238 estimates of computer use duration calculated from the usage monitor data using activity duration cutoffs ranging from 3 to 240 sec in 1-sec increments. Estimates calculated with cutoffs ranging from 28 to 60 sec were highly correlated with the observed duration (Spearman's correlation 0.87 to 0.92) and had nearly ideal linear relationships with the observed duration (slopes and r-squares close to one, and intercepts close to zero). For the same range of cutoff values, when the observed and estimated durations were compared for dichotomous exposure classification across participants, minimal exposure misclassification was observed. It is concluded that activity duration cutoffs ranging from 28 to 60 sec provided unbiased estimates of computer use duration. [Description provided by NIOSH]
• Subjects:
  Biomechanical Phenomena Computers Ergonomics Musculoskeletal Diseases Musculoskeletal System Occupational Health Risk Assessment Risk Factors Safety
• Keywords:
  Biomechanics Computer-equipment Dose-response Mathematical-models Muscles Musculoskeletal-system Musculoskeletal-system-disorders Risk-analysis Risk-factors Statistical-analysis Time-weighted-average-exposure

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• ISSN:
  1545-9624
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article ; Journal Article
• Place as Subject:
  Massachusetts ; OSHA Region 1 ; OSHA Region 10 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH) ; National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health ; Workplace Safety & Health
• Location:
  North America ; North America
• Volume:
  5
• Issue:
  12
• NIOSHTIC Number:
  nn:20034652
• Citation:
  J Occup Environ Hyg 2008 Dec; 5(12):790-796
• Contact Point Address:
  Che-hsu Chang, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02115
• Federal Fiscal Year:
  2009
• Performing Organization:
  Harvard University, Boston, Massachusetts
• Peer Reviewed:
  True
• Start Date:
  19990930
• Source Full Name:
  Journal of Occupational and Environmental Hygiene
• End Date:
  20090831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ed91aae476f7b065017a8c12a5fc083592d1e6b3d162033ac23222cd39eb878b638263d5e80ca3fef1f2cb04481f64ef51a353b7c802fba8a3db73a65d5a72d6
• Download URL:
  https://stacks.cdc.gov/view/cdc/186783/cdc_186783_DS1.pdf
• File Type:
  [PDF - 111.99 KB ]