Occupational exposure to styrene is widespread and has been suggested to be carcinogenic. The aim of this study was to investigate whether occupational exposure to styrene increases the risk of cancer, in particular lymphohematopoietic cancers.
We established a study population of 72,292 workers employed in 443 small and medium-sized companies producing reinforced plastics 1964–2007 by utilizing several national registries, expert assessment, and worker survey data. We identified incident cancer cases from 1968 to 2012 in the national Danish cancer registry and computed standardized incidence rate ratios (SIRs) with 95% confidence intervals (95% CI) based on national rates.
Increasing SIRs of Hodgkin lymphoma, myeloid leukemia, and cancer of nasal cavities and sinuses were inconsistently associated with increasing duration of employment, early year of first employment, or styrene exposure probability. No such trends were observed for cancer of the esophagus, pancreas, lung, kidney, or urinary bladder, which have previously been associated with styrene exposure. Lung cancer showed an overall increased risk that decreased by duration of employment.
Occupational styrene exposure may be associated with Hodgkin lymphoma, myeloid leukemia, and cancer of nasal cavities and sinuses. Further studies are needed to evaluate if the observed associations are likely to be causal.
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From the aDepartment of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark; bCentre for Integrated Register-Based Research, CIRRAU, Aarhus University, Aarhus, Denmark; cDanish Cancer Society Research Centre, Copenhagen, Denmark; dDepartment of Public Health, Section for Epidemiology, Aarhus University, Aarhus, Denmark; and eDepartment of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Submitted 11 September 2015; accepted 28 November 2016.
The study is funded by the Danish Working Environment Research Fund (Grant No.32-2011-09).
The authors report no conflicts of interest.
Data are available for replication through access to Statistics Denmark.
Supplemental digital content is available through direct URL citations in the HTML and PDF versions of this article (www.epidem.com).
Correspondence: Mette Skovgaard Christensen, Department of Occupational Medicine, Aarhus University Hospital, Norrebrogade 44, 2C, DK-8000 Aarhus C, Denmark. E-mail: Mette.S.Christensen@auh.rm.dk.