Lung cancer risk of workers in shoe manufacture and repair

Background The occupational lung cancer risk in manufacturing and repair of shoes was studied by pooling of two major case-control studies from German y. Methods Some 4184 incident hospital-based cases of primary lung cancer and 4253 population controls, matched for sex, age, and region of residence wer e intensively interviewed with respect to their occupational and smoking hi story. Based on the occupational coding and a free text search, all individ uals who had ever worked in shoe manufacturing or repair for at least half a year were identified. Shoemaker-years were calculated as the cumulated du ration of working in shoe manufacturing or repair: Odds ratios (OR) and 95% confidence intervals (CI) were calculated via conditional logistic regress ion. Additional adjustment for smoking and occupational asbestos exposure w as used. Results Seventy-six cases and 42 controls who had ever worked in shoe manuf acture or repair (OR = 1.89, 95% CI: 1.29-2.78). After adjustment for smoki ng, this risk was lowered to 1.69 (95% CI: 1.09-2.62). Further adjustment f or asbestos exposure only slightly changed the risk estimates upwards. The smoking adjusted OR in males was 1.50 (95% CI: 0.93-2.41) and 2.91 (95% CI: 0.90-9.44) in females. Logistic regression modeling showed a positive dose -effect relationship between duration of exposure in shoe manufacture and r epair and lung cancer risk. The odds ratio for 30 years of exposure varied between 1.98 and 2.24 depending on the model specified Conclusions The study demonstrates an increased lung cancer risk for shoema kers and workers in shoe manufacturing. The risk seems to double after bein g 30 years in these occupations.