Primary liver cancer and renal cell carcinoma in laundry and dry-cleaning workers in Denmark

Objectives: Previous studies have shown an excess risk of primary liver cancer among women working in laundries and dry-cleaning shops in Denmark at the time of the census in 1970. During the period 1970-1987, 14 cases of primary liver cancer were observed (standardized mortality ratio 2.7, 95% confidence interval 1.5-4.5). A nested case-referent study was undertaken in order to classify laundry workers and dry-cleaning workers separately. According to hints in the literature, renal-cell carcinomas were also included in this analysis. Methods: Original census forms from 1970 were retrieved from the Danish National Record Office for the 17 cases with primary liver cancer and the 16 cases with renal-cell carcinoma and five matched referents per case. Results: All of the 17 patients with primary liver cancer worked in laundries in 1970, whereas only 74% of the referents worked in laundries. Neither was the risk of renal-cell carcinoma associated with dry-cleaning work (relative risk 0.7, 95% CI 0.2-2.6). Conclusions: The excess risk of primary liver cancer observed for women working in laundries and dry-cleaning shops in Denmark is not likely to be explained by exposure to dry-cleaning solvents. Excessive alcohol consumption is not a likely explanation either, and the excess risk therefore remains unexplained.