We
have
a
substantial
and
consistent
body
of
knowledge
that
demonstrates
the
strong
association
of
MSDs
with
many
exposures
found
in
workplaces
and
have
high
attributable
fractions
for
many
of
these.
Exposure
measures
have
improved
over
the
years
from
initially
just
considering
job
titles,
to
self-reports
of
physical
and
psychosocial
risk
factors,
to
structured
observations,
and
more
recently
to
technical
measures
of
muscle
activity
or
modeled
joint
loads.
Identified
risk
factors
now
include
physical
or
mechanical
factors
(force,
posture,
repetition,
duration),
work
organizational
factors
(worker
perceptions
of
demand,
control,
and
co-worker
and
supervisor
support;
the
so-called
psychosocial
factors)
as
well
as
individual
factors.
These
relationships
have
been
demonstrated
in
multiple
types
of
work,
with
a
wide
variety
of
exposure
assessment
approaches,
and
a
wide
variety
of
study
designs,
including
high-quality
prospective
cohort
studies;
the
NIOSH
MSD
Consortium
Studies
are
an
example
of
a
concerted
attack
on
this
question.
While
it
is
possible
to
identify
risk
factors
without
having
knowledge
of
the
underlying
patho-physiology
using
epidemiological
approaches,
acquiring
a
strong
relationship
between
the
statistical
and
physiological
information
would
give
us
more
confidence
that
the
relationships
are
causal,
and
will
increase
the
likelihood
that
intervening
on
the
risk
factors
will
have
an
effect
on
MSD
development
and
burden.
How
good
are
our
MSD
risk
factors?
We
ask
this
question
because
it
is
possible
to
have
an
excellent
intervention
that
is
based
on
risk
factors
derived
from
a
preceding
etiologic
study,
yet
the
effects
on
MSDs
were
disappointing.
It
may
be
the
risk
factors
themselves
were
misleading,
or
that
the
identified
risk
factors
were
too
far
removed
from
the
target
tissue
pathophysiology,
or
that
the
intervention
itself
was
the
weak
link.
For more information, read the editorial Why have we not solved the MSD problem?, by Dr. Richard Wells.