CASE-CONTROL STUDIES IN CANCER-PATIENTS AS A SURVEILLANCE SYSTEM OF OCCUPATIONAL EXPOSURE IN THE EUROPEAN-COMMUNITY

Study Objective-The main aim was to detect known relationships between lung and blood cancers and various occupational exposures (using job titles as proxies) using a case-control design. The suitability of thi s system for routine surveillance could then be assessed. Design-A cas e-control study was carried out in 1989. Setting-Hospitals in eight Eu ropean Community countries. Subjects-Men aged 25 to 75 years with inci dent and prevalent cancer of the lung (190 cases), haematopietic syste m (210 cases), or gastrointestinal tract (245 controls) were studied. Measurements and main results-The crude estimate of the overall odds r atio exposure (OR) for relevant occupational exposure of lung cancer r elative to gastrointestinal cancer was 1.20 (95% confidence interval ( CI) 0.82, 1.77). In a logistic regression analysis adjusting for count ry, age at diagnosis, smoking, and alcohol consumption, the overall OR was not greatly changed. A significant interaction of occupational ex posure and age at diagnosis showed that lung cancer patients diagnosed at a younger age had a higher OR than patients diagnosed at an older age. Thus, the overall, insignificant result may have been due to a lo w reliability of occupational history in older age or to a selective m echanism related to age. The overall OR for occupational exposure of c ancer of the blood relative to gastrointestinal cancer was 0.88 (95% C I 0.60, 1.31). The logistic regression analysis did not alter these re sults. Conclusion-A surveillance based on a case-control design using job titles would not be sensitive enough to detect possible occupation al risks.