Environment and Breast Cancer: Science Review

Evidence From Humans
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Type of disinfectant in drinking water and patterns of mortality in Massachusetts
Zierler, S., Danley, R. A., Feingold, L. Environ Health Perspect. 1986. 69, 275-9.
Topic area
Environmental pollutant - Drinking water, chlorination byproducts
Study design
Case-control study Other: Ecologic epidemiology
Funding agency
Other: US EPA
Study Participants
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Massachusetts residents who were at least 45 years old and died during 1969-1983. Breast cancer compared with heart, pulmonary, cerebrovascular disease, and lymphatic cancer deaths.
Comment about participation selection
Comparison (chloraminated water) communities tend to have higher population density and lower poverty rate.
Exposures investigated
Chlorinated vs. chloraminated drinking water supply
How exposure was measured
GIS/geographic location
Statistical Analysis
Breast cancer outcome investigated
Mortality from breast cancer from 1969-1983
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.
Communities matched for surface vs. groundwater, population density, % below poverty level
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
Mortality odds ratio, standardized mortality ratio.
Strength of associations reported
Female mortality OR .89 (0.85-0.93) for all controls; 0.97 (0.89-1.05) lymphoma controls
Female SMR chlorinated supply vs. MA residents: 96 (93-100)
Results Comments
Inadequate control for effects of socioeconomic status.
Chlorination has been the major strategy for disinfection of drinking water in the United States. Concern about the potential health effects of the reaction by-products of chlorine has prompted use of alternative strategies. One such method is chloramination, a treatment process that does not appear to have carcinogenic by-products, but may have less potent biocidal activity than chlorination. We examined the patterns of mortality of residents in Massachusetts who died between 1969 and 1983 and lived in communities using drinking water that was disinfected either by chlorine or chloramine. Comparison of type of disinfectant among 51,645 cases of deaths due to selected cancer sites and 214,988 controls who died from cardiovascular, cerebrovascular, or pulmonary disease, or from lymphatic cancer showed small variation in the patterns of mortality. Bladder cancer was moderately associated with residence at death in a chlorinated community (mortality odds ratio = 1.7, 95% confidence interval = 1.3-2.2) in a logistic regression analysis using controls who died from lymphatic cancer. A slight excess of deaths from pneumonia and influenza was observed in communities whose residents drank chloraminated water compared to residents from chlorinated communities, as well as to all Massachusetts residents (standardized mortality ratio = 118, 95% confidence interval = 116-120 for chloraminated communities, and standardized mortality ratio = 98, 95% confidence interval = 95-100 for chlorinated communities). These results are intended to be preliminary and crude descriptions of the relationship under study.(ABSTRACT TRUNCATED AT 250 WORDS)