Risk of cervical cancer among female autoworkers exposed to metalworking fluids

Abstract

Objectives Cervical cancer is caused by human papilloma virus (HPV). However, only a small proportion of women infected with HPV, progress to cervical cancer. Other co-factors must therefore be necessary to cause cervical cancer. We examined cervical cancer in relation to occupational exposure to metalworking fluids (MWF), which are complex mixtures containing several known carcinogens. Methods A cohort of 4374 female autoworkers was followed from 1985-2004 for cancer diagnosis. Based on an elevated standardized incidence rate (SIR), we focused on cervical cancer in an internal analysis. Pooled logistic regression was used to model the relationship between exposure to three different types of MWF, selected constituents, and incidence of cervical cancer. Results Based on 40 cases, the SIR was statistically significantly elevated for both race specific subgroups: 3.30 and 2.43, respectively for Caucasian and African American women. The standard mortality ratio (SMR) was also statistically significantly elevated for Caucasian women (3.44) based on seven observed deaths. There was no association with oil-based straight fluid. Relative risks for soluble and synthetic MWF and nitrosamines were modestly elevated but not statistically significant. Conclusions Water-based MWF may play a role in the etiology of cervical cancer. Further studies in larger cohorts of women are needed to clearly establish this relationship.