4.1. Limitations and strengths of the study
We did not identify, measure, or control for variables in the
analysis, which could have acted as confounding factors. Therefore,
conclusions resulting from the comparison between values of
prevalence rates and the correlation between occupational dermatoses
and type of enterprise might be biased. This deficiency could
be rectified in further research. Nevertheless, there is no reason to
assume that the proportion of employees with dermatoses (either
occupational or nonoccupational) manifested prior to their
appointment in the enterprises studied was significantly different
among the 20 types of enterprises included in our study. Therefore,
prior dermatoses were not considered as a confounding factor.
Clearly, our target populations allowed us to perform a more
valid study compared with any study that would have been carried
out in one enterprise only. Based on our own study, industry specific
studies of occupational dermatoses could be carried out in
Greece.
Another limitation of this study concerns its external validity. Its
internal validity has some value as regards the study population
studied, i.e., the 104 firms, it has no external validity. Our findings are
only indicative with regard to the prevalence of dermatoses in all the
enterprises of the same type in this country. Nevertheless, our study
revealed an occupational health problem in Greece, i.e., that many
cases of occupational diseases do exist. It has two valid conclusions:
there is a need for the establishment of a systematic voluntary
occupational disease recording system in Greece; and more attention
should be paid to the prevention of occupational dermatoses.
Similar circumstances may exist in the same types of enterprises in
other countries, where our study might also be of some use.