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Task-based estimation of mechanical job exposure in occupational groups

Mathiassen, Svend Erik LU ; Nordander, Catarina LU ; Svendsen, S W; Wellman, H M and Dempsey, P G (2005) In Scandinavian Journal of Work, Environment and Health 31(2). p.138-151
Abstract
Objectives This study examined the validity of a common belief in epidemiology with respect to work-related musculoskeletal disorders, that individual mechanical job exposure is better estimated from tasks performed in the job than from the mean exposure of the occupational group. Methods Whole-day recordings of upper trapezius electromyography were obtained from 24 cleaners and 23 office workers. Trapezius activity was analyzed in the level (gap time) and frequency (jerk time) dimensions. On the same day, the job of each person was divided into periods of active work and breaks by means of continuous observations. The bootstrap re-sampling technique was used with this database to compare task-based job-exposure estimates with estimates... (More)
Objectives This study examined the validity of a common belief in epidemiology with respect to work-related musculoskeletal disorders, that individual mechanical job exposure is better estimated from tasks performed in the job than from the mean exposure of the occupational group. Methods Whole-day recordings of upper trapezius electromyography were obtained from 24 cleaners and 23 office workers. Trapezius activity was analyzed in the level (gap time) and frequency (jerk time) dimensions. On the same day, the job of each person was divided into periods of active work and breaks by means of continuous observations. The bootstrap re-sampling technique was used with this database to compare task-based job-exposure estimates with estimates based on the occupational mean. For a particular person, the task-based estimate was obtained by combining the average work and break exposures in the occupation with the personal time proportions of the two tasks in the job. Results The task-based estimates were, in general, equivalent to, or less correct than, occupation-based estimates for both exposure parameters in both occupations and for individual exposures, as well as for group means. This was the result in spite of significant and consistent exposure differences between work and breaks, in particular among the cleaners. Conclusions Even if task exposure contrasts are large, task-based estimates of job exposures can be less correct than estimates based on the occupational mean. Since collecting and processing task information is costly, it is recommended that task-based modeling of mechanical exposure be implemented in studies only after careful examination of its possible benefits. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
occupational epidemiology, activity, muscle, job-exposure matrix, estimation bias, exposure variability, occupational group mean, task-based model
in
Scandinavian Journal of Work, Environment and Health
volume
31
issue
2
pages
138 - 151
publisher
Finnish Institute of Occupational Health
external identifiers
  • pmid:15864908
  • wos:000228618200008
  • scopus:17744398053
ISSN
0355-3140
language
English
LU publication?
yes
id
0a3585b4-2fff-48d3-b50a-a0e1ab665c8d (old id 243869)
date added to LUP
2007-10-05 09:11:01
date last changed
2017-02-12 03:33:33
@article{0a3585b4-2fff-48d3-b50a-a0e1ab665c8d,
  abstract     = {Objectives This study examined the validity of a common belief in epidemiology with respect to work-related musculoskeletal disorders, that individual mechanical job exposure is better estimated from tasks performed in the job than from the mean exposure of the occupational group. Methods Whole-day recordings of upper trapezius electromyography were obtained from 24 cleaners and 23 office workers. Trapezius activity was analyzed in the level (gap time) and frequency (jerk time) dimensions. On the same day, the job of each person was divided into periods of active work and breaks by means of continuous observations. The bootstrap re-sampling technique was used with this database to compare task-based job-exposure estimates with estimates based on the occupational mean. For a particular person, the task-based estimate was obtained by combining the average work and break exposures in the occupation with the personal time proportions of the two tasks in the job. Results The task-based estimates were, in general, equivalent to, or less correct than, occupation-based estimates for both exposure parameters in both occupations and for individual exposures, as well as for group means. This was the result in spite of significant and consistent exposure differences between work and breaks, in particular among the cleaners. Conclusions Even if task exposure contrasts are large, task-based estimates of job exposures can be less correct than estimates based on the occupational mean. Since collecting and processing task information is costly, it is recommended that task-based modeling of mechanical exposure be implemented in studies only after careful examination of its possible benefits.},
  author       = {Mathiassen, Svend Erik and Nordander, Catarina and Svendsen, S W and Wellman, H M and Dempsey, P G},
  issn         = {0355-3140},
  keyword      = {occupational epidemiology,activity,muscle,job-exposure matrix,estimation bias,exposure variability,occupational group mean,task-based model},
  language     = {eng},
  number       = {2},
  pages        = {138--151},
  publisher    = {Finnish Institute of Occupational Health},
  series       = {Scandinavian Journal of Work, Environment and Health},
  title        = {Task-based estimation of mechanical job exposure in occupational groups},
  volume       = {31},
  year         = {2005},
}