Environment and Breast Cancer: Science Review

Evidence From Humans
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Drinking water and cancer in Louisiana. A retrospective mortality study
Gottlieb, M. S., Carr, J. K., Clarkson, J. R. American Journal of Epidemiology. 1982. 116:4, 652-67.
Topic area
Environmental pollutant - Drinking water, chlorination byproducts
Study design
Other: Case-control mortality
Funding agency
Other: US EPA, Louisiana Department of Health and
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
13 Louisiana counties using the Mississippi River, breast cancer deaths and matched non-cancer deaths reported in Louisiana State Mortality data. Controls similar in sex, race, year of death selected from the same county group as the cases. 1960-1975
Comment about participation selection
Cardiovascular deaths, which are "controls," may be related to water quality parameters (e.g. arsenic)
Exposure Investigated
Exposures investigated
Drinking water source at time of death, duration of use at the residence at death, water source at birth. Surface vs. ground source. Length of residence ascertained from water company records, voter's registration, and city directories. Chlorinated vs.
How exposure was measured
Environmental sample
Exposure assessment comment
For half of participants, water source could not be traced back 10 years; so exposure is not known with adequate latency. Ecologic measure, very broad exposure categories. Chlorination likely to be confounded with urbanization, which is related to various breast cancer risk factors. Characteristics of the water source may be spatially correlated with other (e.g. air pollution) geographically based exposures.
Early life exposures considered
Yes, but limited to place of birth
Statistical Analysis
Breast cancer outcome investigated
Mortality from breast cancer
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
White, nonwhite
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.
Occupation. Inadequate control of breast cancer risk factors, which may be related to geographic location.
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
Surface vs. groundwater at death: OR = 1.21 (95% CI 1.00-1.46) (chi-square p < .05).
Surface vs. groundwater estimated lifetime water use: OR = 1.30 (95% CI 1.00-1.69) (chi-square p < .05).
No association in analysis limited to nonwhites.
Chlorinated vs. nonchlorinated: OR = 1.51 (95% CI 1.16-1.95) (chi-square p < 0.01)
Results Comments
Drinking water from the Mississippi River is characterized by high levels of organic compounds. Although the study design has many weaknesses, this study serves as hypothesis-generating evidence.