education among women only (P = 0.02) were the only
variables clearly associated with psychological distress.
Table 3 presents prevalence of psychological distress
according to working characteristics and prevalence ratios
of this association. After adjusting for age, education, and
per capita monthly income, men and women classified in
the high strain quadrant of the job strain model and those
reporting high demands and low control separately were
more likely to experience psychological distress. Low
support at work showed the clearest association with
psychological distress in both sexes, but especially among
men. Having a routine-non-manual or manual work was
associated with psychological distress in men but not in
women. Subsequently we adjusted each work characteristic
for all the other work features simultaneously in order to test
whether these effects were mutually confounded (Model 2).
As it can been seen, this resulted in a reduction of the
strength of the association between all job strain variables
and the prevalence of psychological distress. For those in
the high strain quadrant, the association remained significant
(PR = 1.30; 95% CI 1.0–1.7 for men and PR = 1.43;
95% CI 1.2–1.7 for women) after these adjustments.
However the association between job demands and control
sub-scales with psychological distress was attenuated in
women and disappeared in men. Low support at work
remained clearly associated with psychological distress for