Environment and Breast Cancer: Science Review

Evidence From Humans
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Breast cancer risk and the combined effect of environmental estrogens
Ibarluzea Jm, J., Fernandez, M. F., Santa-Marina, L., Olea-Serrano, M. F., Rivas, A. M., Aurrekoetxea, J. J., Exposito, J., Lorenzo, M., Torne, P., Villalobos, M., Pedraza, V., Sasco, A. J., Olea, N. Cancer Causes and Control. 2004. 15:6, 591-600.
Topic area
Environmental pollutant - Pesticides, organochlorine, DDE, DDT, Aldrin, Endo
Study design
Hospital based case-control
Funding agency
Other: Spanish Ministry of Health and the European
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 260
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cases were recruited from among women undergoing breast cancer surgery in three public hospitals, age 35 to 70 years at time of surgery. Cases included invasive and in situ cancers. Controls were women undergoing non-cancer related surgery. Ex: previous history of breast cancer; had gynecological or endocrine disease; non-caucasian.
Comment about participation selection
Most of the controls underwent surgery for diseases of the gall bladder and hernia which are associated with obesity as a risk factor; more controls in the highest quintiles of BMI than in the lower two quintiles;
Exposure Investigated
Exposures investigated
Adipose tissue concentrations (from breast for cases, from abdomen for controls) of DDE, Aldrin, Endosulfan-ether, Lindane, and TEXB. BMI
How exposure was measured
Biological Questionnaire, in person (does not specify how anthropometric data was obtained)
Exposure assessment comment
Strengths: developed and utilized a standardized method to assess the total effective xenoestrogen burden (TEXB) in human adipose tissue and serum; conducted in-person interviews. Limitations: does not state method of obtaining BMI; used breast fat as the adipose tissue analyzed for cases and abdominal fat for controls; only stratifies BMI by >median and by < median in table.
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Caucasian origin
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.
Confounding was adequately controlled for. Confounders considered: marital status, education, social class, occupation, number of full-term pregnancies, age at first full term pregnancy, months of lactation, BMI, family history of bc, oc use, HRT use, men
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Description of major analysis
ORs were calculated using unconditional logistic regression. Analyses were stratified by menopausal status, BMI, and parity. Body size analysis considered xenoestrogens and total effective xenoestrogen burden (TEXB) as effect modifiers
Strength of associations reported
Only Aldrin was associated with a statistically significantly increased risk of breast cancer among all women.
However among women with BMI below the median, those with the highest concentrations of TEXB-alpha showed a significantly elevated OR of 2.44 (1.03-5.78).
Among postmenopausal women, Aldrin, Lindane, and TEXB-beta (3rd quartile only) were all associated with significantly elevated risks.
Association between breast cancer risk in women with a high concentration of TEXB-alpha xenoestrogen, >197.51 picomolars of Estradiol equivalent per gram of lipid vs. <0.25, who also have a BMI less than 28.4, OR=2.44(1.03-5.78) trend p=0.03
Results Comments
Strength; assessed the relationship between BMI and xenoestrogen levels with breast cancer risk; found a strong relationship between leaner women with high levels of estradiol equivalent in the alpha-fraction and breast cancer risk
Author address
Department of Health Guipuzkoa, San Sebastian, Basque Country, Spain.