Abstract
The literature is sparse on reproducibility of
self-reported exposure to physical ergonomics risk
factors for musculoskeletal disorders (MSDs). Aims of
this study were to evaluate, in a cohort of workers
interviewed up to three times: 1-year test-retest
reliability; and 5- and 6-year recall of physical
exposures. We also examined whether reproducibility was
influenced by the presence of UE MSD or by
technological changes introduced between the last two
surveys.Methods A cohort of automobile manufacturing
employees was interviewed at baseline, one and six
years later about work history, physical and
psychosocial exposures at work, upper limb symptoms,
injury and medical history, and demographics. Agreement
between interviews was evaluated by intraclass
correlation and Spearman coefficients. Differences in
exposure between 1- and 6-year follow-up were analyzed
by Wilcoxon matched-pairs signed-ranks test.Results
Large and significant decreases in work pace and
physical effort were observed from baseline, although
an upper extremity composite index was quite stable in
the total population. One-year test-retest reliability
was fair to good for the composite exposure index
(ICC=0.58), whole-body vibration, handling parts, and
tool use, but poor for the other variables considered.
Long-term reproducibility, from baseline or 1-year
follow-up to 6-year follow-up, was poor for the
composite index and almost all single items. UE MSD
case status influenced 1-year test-retest reliability,
with subjects who changed case status from baseline
displaying higher reliability, but not reproducibility
of recalled exposures. A strong regression to the mean
effect was observed on exposures reported at follow-up
surveys.Conclusions Recalled ergonomics exposures could
be employed in retrospective cohort studies as a
somewhat reliable and unbiased estimate of the
self-reported exposures that would have been obtained
up to one year earlier, but not over a longer period
(5-6 years). These longer-term results may have been
limited by difficulty in matching jobs between
interviews; also the regression to the mean effect
likely contributed to reduce agreement. Changes in
production technology and work organization produced a
decrease in physical workload intensity and job pace,
but did not have a substantial impact on an exposure
index for the upper limb.,
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