Environment and Breast Cancer: Science Review

Evidence From Humans
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An updated investigation of cancer incidence and mortality at a Scottish semiconductor manufacturing facility with case-control and case-only studies of selected cancers
Darnton, A., Miller, B. G., Maccalman, L., Galea, K. S., Wilkinson, S., Cherrie, J. W., Shafrir, A., McElvenny, D., Osman, J. Occup Environ Med. 2012. 69:10, 767-9.
Topic area
Environmental pollutant - Occupation
Study design
Retrospective cohort
Funding agency
Health and Safety Executive
Study Participants
Number of Cases
46 female cases
Menopausal Status
The menopausal status of women included in this study is listed here.
No analyses by menopausal status
Number in Cohort
Cohort: 4,388 men and women
Cohort participation rate
Not applicable. This study was records-based.
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
The cohort consists of 4,388 men and women employed at a semiconductor factory in Scotland between opening in early 1970s through April 1999. Cases were identified using the NHS Central Register and were invited to participate via general practitioners.
Comment about participation selection
General population, including both workers and non-workers, may not be an appropriate comparison group.
Exposure Investigated
Exposures investigated
Self-reported job histories at the semiconductor factory, including exposure to: acids, solvents, gases, antimony trioxide, arsenic and compounds, carbon tetrachloride, ceramic fibre, chromium, trichloroethylene, sulfuric acid mist, ionizing radiation, RF
How exposure was measured
Questionnaire, in person
Exposure assessment comment
Cumulative exposure was measured according to duration of employment, date of first employment, whether or not workers were assigned to work in wafer fabrication areas prior to employment, and time since first employment at the factory. Factory hazard exposure comparisons were adjusted by 0-, 5-, and 10-year lags to allow for disease latency. A historical hygiene assessment was conducted to gather information about processes and working practices since the plant began operations in 1972. Employment outside the plant was assigned exposures via the Finnish FINJEM job-exposure matrix. Questionnaires on individual job histories and lifestyle were administered by nurses.
Breast cancer outcome investigated
Primary incident breast cancer
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.
Age, calendar period, Carstairs quintile (deprivation index)
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
Ever worked at semiconductor manufacturing facility: SIR 122 (95% CI 90-163)
Ever worked at semiconductor manufacturing facility, 10 year lag: SIR 109 (95% CI 73-156)
Results Comments
Authors also conducted case-control analyses within the factory cohort with individual job histories from questionnaires and historical hygiene assessment (for employment in the plant) and Finnish job-exposure matrix (FINJEM) (for work employment outside the plant) to assess individual exposure to hazards including acids, solvents, and arsenic. No significant findings from these analyses, which were based on 20 cases and 83 age-matched controls and were adjusted for "lifestyle factors."
Author address
Health and Safety Executive, Epidemiology Unit, Redgrave Court, Merton Road, Bootle, Merseyside L20 7HS, UK. andrew.darnton@hse.gsi.gov.uk
Reviewers Comments
This study was limited by the lack of control for breast cancer risk factors.