This study may have some limitations. First, a cross-sectional design may restrict causal relations.
This can be addressed in a prospective cohort study. Another limitation is that in evaluating solvent exposure we relied on environmental monitoring alone. Workers were in separate working environments, which facilitated group classification and exposure assessment, but further studies should consider using biological monitoring instead. Besides, we were not
able to calculate cumulative occupational exposure because the information on previous levels of exposure
was not available.
We investigated the effects of mixed organic solvents on hypertension, but not the effects of single solvents.
However, organic solvent mixtures are more common in workplaces.