Abstract B60: Breast cancer risks among Vietnamese nail salon workers in California

Background: Recently, considerable public attention has focused on the safety of personal care products, which, although largely unregulated, are known to contain carcinogens and endocrine disruptors, including methylene chloride, toluene, formaldehyde, phthalates and 1,4-dioxane. Health concerns have been particularly pronounced for nail salon workers, who are exposed daily to an array of toxic compounds and are likely to have substantially greater exposures than does the general population. Yet, to date, there have been no cancer studies focused on this workforce. In the past two decades, the demographics of this workforce have shifted dramatically and the nail salon sector has tripled in size in California. Of particular note, this workforce is now heavily represented by Vietnamese women, who, due to their lower English proficiency, may often not be well trained in handling the hazardous compounds they routinely use and may consequently be disproportionately exposed. The combination of harmful occupational exposures, language barriers, inadequate ventilation and lagging regulatory standards underscore the importance of a breast cancer study focused on this workforce.

Objective: We evaluated whether nail salon workers licensed in California have an excess incidence of breast cancer compared to the general female population in California. Furthermore, we examined whether this disparity is particularly acute among Vietnamese female workers, who currently dominate the workforce.

Methods: Through a series of probabilistic record-based linkages of California's statewide cosmetology worker licensee files to the California Cancer Registry and the state's vital statistics records, we were able to identify breast cancer cases and rigorously construct person-years in order to calculate standardized incidence ratios (SIR). Because the licensee file does not contain information on race/ethnicity, we applied a name-listed methodology to identify workers of Vietnamese ancestry, with enhancements based on self-identified race/ethnicity information from their offspring's birth files, in order to calculate SIR in this ethnic population.

Results: Between 1970 and 2006, there were 254,674 female cosmetologists (providing hair and nail services) and 141,276 manicurists (providing nail services only). Based on the names-list method, approximately 8% of cosmetologists but over 50% of manicurists were Vietnamese women over the full time period. Since 1990, Vietnamese women have comprised two-thirds of newly-licensed manicurists. We identified 4,164 female breast cancer cases (invasive and in situ) prospectively diagnosed among California licensees, of which 346 were of Vietnamese descent. Preliminary age-adjusted SIRs and 95% confidence intervals will be presented.

Conclusion: California has a large number of women who are current or former nail salon workers, with Vietnamese women comprising a large proportion of the workforce. Preliminary analyses indicate a large number of breast cancer cases in this worker cohort. Findings from this study may help elucidate the relationship between cosmetic compounds and cancer, a topic with public policy implications for workers as well as consumers. Furthermore, specific findings for Vietnamese workers, may offer valuable contributions to cancer control efforts for this underserved, but potentially high risk, population.