Working environment and myeloproliferative neoplasm: A population-based case-control study following a cluster investigation

Background: Occupational exposures, including those to polycyclic aromatic hydrocarbons (PAH), are suspected risk factors for myeloproliferative neoplasms (MPN). Methods: We investigated occupational exposures and MPN risk (54 cases and 472 controls) in a population-based case-control study in three rural Pennsylvania counties. Occupational histories, coded to SIC/SOC 1980, were linked to a previously created PAH job-exposure matrix. Odds ratios for industry (17 categories), occupation (26 categories), and PAH exposure were adjusted using logistic regression. Results: No industries or occupations were strongly or consistently associated with increased MPN risk. Analysis of employment duration found that being employed for 5 or more years in transportation, communications, and other public utilities was associated with MPN risk. There was no indication of an association with cumulative PAH exposure. Conclusions: These few associations did not appear to have a common exposure. This exploratory study does not support the hypothesis that occupational exposure, including PAH, are strong risk factors for MPNs.