A Mailed-questionnaire Survey of Ex-workers: A Tool to Evaluate the Healthy-worker Effect in Cross-sectional Studies.
In order to evaluate a possible healthy-worker effect in a cross-sectional study in a viscose rayon plant, a survey of ex-workers was conducted. From the personnel records of this factory, 475 male, Caucasian, Dutch-speaking, carbon disulfide (CS&inf2;)-exposed workers who had been employed ten years prior to the cross-sectional study were selected for study. Of these, 142 were still employed in the same plant, and 64 were deceased. Retrieval of the causes of death proved impossible. A questionnaire was mailed to the remaining 269 men, of whom 149 completed and returned it. Eighty-nine subjects reported having left the plant for health reasons. Among the health reasons specified, eye-irritation complaints were most often mentioned (53.7%), followed by gastrointestinal complaints (32.8%), complaints concerning the central nervous system (19.4%) and the peripheral nerves (11.9%), heart or lung problems (14.9%), and problems affecting the skin (9.0%). The average duration of employment decreased significantly with the intensity of the exposure to CS&inf2;. The results suggest that the findings of a cross-sectional study of current workers in the same viscose rayon plant may represent underestimates of some conditions, in particular the acute eye-irritation complaints. Other complaints with high prevalences in the cross-sectional study, such as complaints consistent with polyneuropathy, seemed less, while others, such as impotence, seemed not at all, subject to underestimation.
Vanhoorne
MH
Department of Public Health, Occupational and Environmental Health Section, State University of Ghent, University Hospital, De Pintelaan, 185, 9000 Ghent, Belgium.
De Smet FP
De Fruyt FK
Seghers
KE
De Bacquer DA