Multiple Myeloma and lifetime occupation: results from the EPILYMPH study

Background: The EPILYMPH study applied a detailed occupational exposure assessment approach to a large multi-centre case-control study conducted in six European countries. This paper analysed multiple myeloma (MM) risk associated with level of education, and lifetime occupational history and occupational exposures, based on the EPILYMPH data set. Methods: 277 MM cases and four matched controls per each case were included. Controls were randomly selected, matching for age (+/- 5 years), centre and gender. Lifetime occupations and lifetime exposure to specific workplace agents was obtained through a detailed questionnaire. Local industrial hygienists assessed likelihood and intensity for specific exposures. The odds ratio and 95% confidence intervals (OR, 95% CI) were calculated for level of education, individual occupations and specific exposures. Unconditional logistic regression models were run for individual occupations and exposures. Results: A low level of education was associated with MM OR = 1.68 (95% CI 1.02-2.76). An increased risk was observed for general farmers (OR = 1.77; 95% CI 1.05-2.99) and cleaning workers (OR = 1.69; 95% CI 1.04-2.72) adjusting for level of education. Risk was also elevated, although not significant, for printers (OR = 2.06; 95% CI 0.97-4.34). Pesticide exposure over a period of ten years or more increased MM risk (OR = 1.62; 95% CI 1.01-2.58). Conclusion: These results confirm an association of MM with farm work, and indicate its association with printing and cleaning. While prolonged exposure to pesticides seems to be a risk factor for MM, an excess risk associated with exposure to organic solvents could not be confirmed