Environment and Breast Cancer: Science Review

Evidence From Humans
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Cancer incidence in a group of workers potentially exposed to ethylene oxide
Norman, S. A., Berlin, J. A., Soper, K. A., Middendorf, B. F., Stolley, P. D. Int J Epidemiol. 1995. 24:2, 276-84.
Topic area
Environmental pollutant - Ethylene oxide, occupation
Funding agency
Johnson & Johnson Company
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Not reported
Number of Controls
1,132 (82% female, 12% of females were regular employees); 342 female regular employees
Cohort participation rate
Greater than 70%; 31% loss to followup after 1984;
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Participants of the Health Appraisal Project; regular and temporary employees at a plant with exposure to ethylene oxide followed 1982-1987
Comment about participation selection
Median duration of employment for regular female employees was 822 days; 90 days for temporary employees. Loss to follow-up may result in bias. 65% of person-years were women under 45, young for breast cancer.
Exposures investigated
Work in plant where exposure to ethylene oxide was documented by sampling.
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Not adequately controlled
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Strength of associations reported
Regular employees
1985 RR 2.55 (1.31-4.98) 8 cancers, study participants not lost to follow-up
1986 RR 2.09 (1.10-3.95) 9 cancers, including women lost to follow-up and searched in NY Cancer Registry data
1987 RR 1.88 (0.99-3.58) 9 cancers, including women lost to follow-up and searched in NY Cancer Registry data
Results Comments
Loss to follow-up after 1985 is problematic. Lag time of 11 years or less between beginning of employment and diagnosis means that some cancer may predate exposure.
Author address
Center for Clinical Epidemiology and Biostatics, University of Pennsylvania, Philadelphia 19104, USA.