title: Breast cancer risk after occupational solvent exposure: the influence of timing and setting.
abstract: Organic solvents are ubiquitous in occupational settings where they may contribute to risks for carcinogenesis. However, there is limited information on organic solvents as human breast carcinogens. We examined the relationship between occupational exposure to solvents and breast cancer in a prospective study of 47,661 women with an occupational history in the Sister Study cohort. Occupational solvent exposure was categorized using self-reported job-specific solvent use collected at baseline. Multivariable Cox regression analyses were used to assess breast cancer risk, adjusting for established breast cancer risk factors. A total of 1,798 women were diagnosed with breast cancer during follow-up, including 1,255 invasive cases. Overall the risk of invasive breast cancer was not associated with lifetime exposure to solvents [HR, 1.04; 95% confidence interval (CI), 0.88-1.24]. Parous women who worked with solvents before their first full-term birth had an increased risk of estrogen receptor-positive invasive breast cancer compared with women who never worked with solvents (HR, 1.39; 95% CI, 1.03-1.86). A significantly elevated risk for estrogen receptor-positive invasive breast cancer was associated with solvent exposure among clinical laboratory technologists and technicians (HR, 2.00; 95% CI, 1.07-3.73). Occupational exposure to solvents before first birth, a critical period of breast tissue differentiation, may result in increased vulnerability for breast cancer. Our findings suggest a need for future studies in this area to focus on exposure time windows and solvent types in different occupational settings.
authors.affiliation: Authors' Affiliations: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Department of Health and Human Services, Research Triangle Park, North Carolina; and Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway christine.ekenga@nih.gov.
authors.forename: Christine C
authors.initials: CC
authors.lastname: Ekenga
authors.affiliation: Authors' Affiliations: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Department of Health and Human Services, Research Triangle Park, North Carolina; and Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: Christine G
authors.initials: CG
authors.lastname: Parks
authors.affiliation: Authors' Affiliations: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Department of Health and Human Services, Research Triangle Park, North Carolina; and Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: Aimee A
authors.initials: AA
authors.lastname: D'Aloisio
authors.affiliation: Authors' Affiliations: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Department of Health and Human Services, Research Triangle Park, North Carolina; and Department of Global Public Health and Primary Care, University of Bergen, Bergen, NorwayAuthors' Affiliations: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Department of Health and Human Services, Research Triangle Park, North Carolina; and Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: DeRoo
authors.affiliation: Authors' Affiliations: Epidemiology Branch, National Institute of Environmental Health Sciences, NIH, Department of Health and Human Services, Research Triangle Park, North Carolina; and Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: Dale P
authors.initials: DP
authors.lastname: Sandler
mesh_terms: D001943:Breast Neoplasms / Q000139:chemically induced* / Q000453:epidemiology / Q000378:metabolism; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced* / Q000453:epidemiology / Q000378:metabolism; D016273:Occupational Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D011446:Prospective Studies; D011647:Puerto Rico / Q000453:epidemiology; D011960:Receptors, Estrogen / Q000378:metabolism; D012307:Risk Factors; D057566:Self Report; D012997:Solvents / Q000506:poisoning*; D014481:United States / Q000453:epidemiology
chemical_list: D011960:Receptors, Estrogen; D012997:Solvents