Study on postural stress and shoulder disorders - authors' reply.
Scand J Work, Environ & Health 2001 Feb; 27(1):82-83
We thank Drs Bonde & Kolstad for their thoughtful reading of our study. The questions that they raise are of interest to investigators of episodic events with sometimes poorly delineated onset. In our study of shoulder musculoskeletal disorders, in a unionized workplace, a few workers (but probably not all) who developed pain and functional limitation were able to obtain transfers to less physically stressful jobs. Thus to link a case to the current job at the time of interview would have risked underestimation of the etiologically relevant exposures. However, it is also true that reliance on a subject`s recall to identify the job at onset risks overestimation if "onset" is interpreted by the worker to mean "onset of such severe pain that I could no longer tolerate it" rather than "when I first felt any shoulder discomfort". We did not have access to data regarding how much job mobility had actually been exercised in relation to musculoskeletal symptoms, and therefore we could not determine the number of cases that had held different jobs at the 2 moments in the progression of their condition. We agree that the selection of the appropriate point in time for the assessment of exposures is a methodological challenge in the study of musculoskeletal disorders.
Posture; Musculoskeletal-system-disorders; Muscular-disorders; Muscle-stress; Etiology; Muscle-tension
Univ Massachusetts, Dept Work Environm, 1 Univ Ave, Lowell, MA 01854 USA
Scandinavian Journal of Work, Environment and Health