Wet work exposure: comparison of observed and self-reported data

Purpose Wet work is the most important exposure leading to occupational hand eczema; however, the prevalence and character of wet work in various wet work professions remain not fully covered. Self-reported data are widely used in studies of wet work although the validity of these remains uncertain. The objective of the present study is to provide information on validity of self-reported wet work exposure in different professions by comparing work place observations with self-reported data. Methods 114 workers from 15 various wet work professions were observed. The observations covered duration and frequency of wet work activities. The observed population as well as a non-observed population from each work place were given a questionnaire covering the same wet work activities. Results Correspondence analysis between self-reported and observed wet work showed that misclassification was larger regarding duration than frequency. 29.2% overestimated and 23.9% underestimated total wet work with more than 2 h/day. Professions with high wet work prevalence overestimated duration of wet work activities, but underestimated frequency. Females overestimated frequency, but not duration. The observed group (45%) significantly more often, than the non-observed group (32%), reported having more than 2 h of wet work/day (OR 2.8, 95% CI 1.6–4.9). Sensitivity and specificity of the questionnaire regarding total wet work in the observed population showed 51% sensitivity and 59% specificity. Conclusion Over- and underestimation of wet work were found to be equally distributed. The correspondence analyses illustrate a noticeable misclassification between the estimations and the observations on all wet work variables, but largest for total wet work.