Environment and Breast Cancer: Science Review

Evidence From Humans
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Circulating levels of sex hormones and their relation to risk factors for breast cancer: a cross-sectional study in 1092 pre- and postmenopausal women (United Kingdom)
Verkasalo, P. K., Thomas, H. V., Appleby, P. N., Davey, G. K., Key, T. J. Cancer Causes & Control. 2001. 12:1, 47-59.
Topic area
Body size - Physical Activity
Study design
Other: Cross sectional analysis
Funding agency
Other: Finnish Cancer Foundations, Finnish Medical
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number in Cohort
Cohort: 1,092 (636 pre) (456 post)
Cohort participation rate
No, only 1,092 of 16,910 eligible women participat
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: recruited for the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford study between 1994 and 1995; resident of the UK; age 20 or older at recruitment; 10 or more menstrual periods in the past 12 months (pre); most recent menstrual cycle was less than 40 days long (pre); no menstrual periods in the past 12 months (post) Ex: used exogenous sex hormones or were pregnant at blood draw or when responding to questionnaire; unknown number of menstrual periods in the past 12 months; did not know the day of their menstrual cycle when the blood sample was collected; undergone a hysterectomy and were under 60 yrs of age; undergone an oophorectomy; had a previous cancer
Comment about participation selection
Strengths: fairly large study group; stratified by menopausal status; assay for postmenopausal estradiol was optimized to measure very low concentrations; adjusted for all relevant covariates; analyzed the mechanistic relationship of circulation sex hormones (including Sex Hormone-Binding Globulin) by anthropometric measurements and physical activity; looked at exercise and physical activity at work; anthropometric data measured by trained staff Limitations: only one blood sample was assayed for premenopausal women; many exclusion factors; low participation rate;
Exposures investigated
BMI and W/H ratio, sex hormones
How exposure was measured
Questionnaire Anthropometric measurement, researcher-administered Biological
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.
Adequately controlled, Confounders: time of blood draw, hours since last meal before blood draw, days blood sample was in the mail, years blood sample was in storage, age, BMI, W/H ratio, physical activity at work, vigorous exercise, current alcohol consu
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Results Comments
SHGB decreased with increasing BMI and W/H ratio in both pre and post women. Estradiol levels increased with increasing BMI in post women. Estradiol levels decreased with increasing physical activity in pre women.
Author address
Imperial Cancer Research Fund Cancer Epidemiology Unit, University of Oxford, UK. p.verkasalo@icrf.icnet.uk