Environment and Breast Cancer: Science Review

Evidence From Humans
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Occupation and occupational exposure to endocrine disrupting chemicals in male breast cancer: a case-control study in Europe
Villeneuve, S., Cyr, D., Lynge, E., Orsi, L., Sabroe, S., Merletti, F., Gorini, G., Morales-Suarez-Varela, M., Ahrens, W., Baumgardt-Elms, C., Kaerlev, L., Eriksson, M., Hardell, L., Fevotte, J., Guenel, P. Occup Environ Med. 2010. 67:12, 837-44.
Topic area
Environmental pollutant - Occupation PCBs dioxin phthalates alkylphenolic c
Study design
Mix of hospital and population based case-control
Funding agency
European Commission Denmark: The Strategic Environ
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Study restricted to men
Number of Controls
Controls: 1,901
Country where study was conducted
Denmark, France, Germany, Italy, Sweden Latvia, Po
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cases were men aged 35-70 living in Denmark, France (10 regions), Germany (5 regions), Italy (3 regions), Latvia, Portugal (2 regions), Spain (3 regions) or Sweden (4 regions) and diagnosed with breast cancer between the years of 1995 and 1997. Cases were identified through contact with local clinical and pathology departments, and each case was reviewed by a pathologist. Controls were randomly selected during case recruitment from population registers in Denmark, Italy, and Sweden, from electoral rolls in France, and from municipality registers in Germany. Hospital based cancer controls were randomly selected in Latvia and Spain from among incident colon cancer patients and in Portugal from among colon and stomach cancer patients.
Comment about participation selection
The authors report that occupational exposure to chemicals is not known to play a role in colon cancer. Controls were selected only in study areas where at least one male breast cancer patient was included. The differences in control participation rate by country may reflect selection bias. However, restricting analyses to countries with high participation rates among controls (France, Italy) did not alter the findings.
Exposure Investigated
Exposures investigated
Occupation, industry, and estimated cumulative occupational exposure to endocrine disrupting compounds (EDC) assessed from detailed occupational questionnaires that captured information on production, work tasks, equipment and chemicals used for each job
How exposure was measured
Job history Questionnaire, in person (France, Italy, Germany, Latvia, Spain, Portugal) Questionnaire, by telephone (Denmark, Sweden)
Exposure assessment comment
The use of expert exposure assessment on an individual basis, rather than a job exposure matrix, may have produced more refined exposure estimates. Many of the occupations have exposures to other potentially endocrine disrupting chemicals that were not assessed in the cumulative exposure score. The selection of chemicals for the cumulative exposure score was based on expert judgment and a literature review.
Breast cancer outcome investigated
Primary incident breast cancer (male)
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, country, study area, education, BMI, and alcohol consumption
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
Compared to those who never worked as/in:
Motor vehicle mechanics (9 cases): aOR 2.1 (95% CI 1.0-4.4)
Painters (7 cases): aOR 2.3 (95% CI 1.0-5.2)
Wood preparation workers, paper makers (5 cases): aOR 2.4 (95% CI 0.9-6.5)
Forestry/logging (7 cases): aOR 2.4 (95% CI 1.0-5.6)
Manufacture of rubber and plastic (6 cases): aOR 1.9 (95% CI 0.8-4.6)
Manufacture of electrical machinery (5 cases): aOR 2.0 (95% CI 0.8-5.3)
Sale and repair of motor vehicles: aOR 1.8 (95% CI 1.0-3.2)
Health and social work (8 cases): aOR 2.3 (95% CI 1.1-5.1)
Manufacture of furniture (9 cases): aOR 1.8 (95% 0.9-3.7)

≥ Median cumulative exposure score (Ref = not exposed):
Alkylphenolic compounds (7 cases): aOR 3.3 (95% CI 1.1-9.9)
Phthalates (3 cases): aOR 0.8 (95% CI 0.2-3.7)
PCBs and dioxins (9 cases): aOR 1.6 (95% CI 0.7-3.7)

Pesticides cumulative exposure score (ref = not exposed):
Tertile 1 (7 cases) aOR 0.9 (95% CI 0.4-2.1)
Tertile 2 (10 cases) aOR 1.2 (95% CI 0.6-2.4)
Tertile 3 (10 cases) aOR 0.8 (95% CI 0.4-1.7)
Results Comments
Combining PCBs and dioxins exposure assessment limits interpretation somewhat. Men who worked >10 years as motor vehicle mechanics had a higher risk of breast cancer (OR 5.9; CI not reported) compared to men who had never worked as motor vehicle mechanics. Unfortunately the study did not report risks for other occupations by duration of exposure.
Author address
CESP-INSERM (National Institute of Health and Medical Research), Villejuif, France.
Reviewers Comments
General population, including both workers and non-workers, may not be an appropriate comparison group. A strength of this study is that it is a large cohort of male breast cancer cases, with a high participation rate. Additional occupations/industries were considered. We focused on (1) significant positive associations (2) if a particular job or sector was significantly associated with breast cancer in at least one study in our review, we report results from all other studies that considered that sector, regardless of significance. It is important to note that job coding criteria generally differ across studies. The exposure assessment by occupation helps address concerns about studying individual chemicals independently, and indeed the authors note that workers in their study were often exposed to more than one EDC. However there may be significant variation in duration and intensity of exposure to job-related chemicals between individuals classified as being part of the same industry or even the same occupation.