Environment and Breast Cancer: Science Review

Prenatal diethylstilbestrol exposure and risk of breast cancer
Palmer, J. R., Wise, L. A., Hatch, E. E., Troisi, R., Titus-Ernstoff, L., Strohsnitter, W., Kaufman, R., Herbst, A. L., Noller, K. L., Hyer, M., Hoover, R. N. Cancer Epidemiol Biomarkers Prev. 2006. 15:8, 1509-14.

Topic area
Early life exposures
Early life exposures
Study design
Prospective cohort
Prospective cohort
Funding agency
NCI
NCI

Study Participants
Number of Cases
102
102
Number in Cohort
Cohort: 6890
Cohort: 6890
Cohort participation rate
More than 70%
More than 70%
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
In: DES-exposed participants of four existing cohorts that had an appropriate comparison group of unexposed persons and had medical record documentation of exposure or nonexposure. Unexposed cohort comprised women unexpected to have exposure from the same four cohorts that provided the exposed subjects.
Ex: Never located, missing date of birth, deceased before 1978, lost or refused before 1978, cancer before entry in the study.
Comment about participation selection
Exposed and unexposed participants were recruited from four different cohorts. Long follow-up.
Exposed and unexposed participants were recruited from four different cohorts. Long follow-up.

Exposure Investigated
How exposure was measured
Medical records
Medical records
Exposure assessment comment
Medical records were available on DES exposure status. DES exposures were assessed at different times for four cohorts, which might induce a cohort effect and exposure level may differ over time.
Medical records were available on DES exposure status. DES exposures were assessed at different times for four cohorts, which might induce a cohort effect and exposure level may differ over time.

Statistical Analysis
Breast cancer outcome investigated
Primary invasive breast cancer
Primary invasive breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
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, years of education, number of births, age at 1st birth, age at menarche, use of female hormon supplements, use of oral contraceptives, family history of breast cancer, birth weight and cohort
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
No
Description of major analysis
Multivariate Cox proportion hazards regression was used to compute hazard ratio and 95% CI, with stratification on individual year of age, and strata of breast cancer risk factors. Analysis of timing of first use in relation to breast cancer risk was perf
Multivariate Cox proportion hazards regression was used to compute hazard ratio and 95% CI, with stratification on individual year of age, and strata of breast cancer risk factors. Analysis of timing of first use in relation to breast cancer risk was perf
Strength of associations reported
1.40 (0.86 - 2.29)
1.40 (0.86 - 2.29)
Results Comments
Women with prenatal exposure to DES had an increased risk of breast cnacer, especially after age 40.
Women with prenatal exposure to DES had an increased risk of breast cnacer, especially after age 40.

Author address
Slone Epidemiology Center, Boston University, 1010 Commonwealth Avenue, Boston, MA 02215, USA. jpalmer@slone.bu.edu
Slone Epidemiology Center, Boston University, 1010 Commonwealth Avenue, Boston, MA 02215, USA. jpalmer@slone.bu.edu