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The Newton Breast Cancer Study The Newton Breast Cancer Study was initiated as follow-up to research by the Massachusetts Department of Public Health (MDPH) that identified areas of high and low incidence in Newton, ranging from 22% below to 55% above the statewide rate for the period 1982-1992. The study, conducted by Silent Spring Institute, investigated differences between the high- and low-incidence areas in factors known or hypothesized to affect breast cancer risk. The study involved approximately 1,350 Newton women who responded to a questionnaire about their health history, individual characteristics and habits, and home environments.
Because income and education are not themselves causes of breast cancer, further analysis investigated whether the well-known association between SES and breast cancer risk may be the result of environmental exposures. Results showed that significantly greater use of certain products among higher SES women contributed to differences between high- and low-incidence areas.
These findings are intriguing because many pesticides contain endocrine disrupting compounds (EDCs) that mimic our natural hormones. Exposure to EDCs is an emerging area of study for breast cancer risk. Since a woman's lifetime exposure to natural estrogen is linked to higher breast cancer risk, exposure to compounds that mimic estrogen and other hormones may also increase risk. Higher rates of mammography and breast self-exam in high-incidence areas are likely to contribute to higher reported breast cancer rates: 27% of women in high-incidence areas said they had had 10 or more mammograms, compared with 17% in low-incidence areas. Because screening leads to earlier diagnoses, it may contribute to temporarily higher reported incidence. The higher proportion of Jewish women in high-incidence areas
did not account for the difference in incidence between the
study areas. |
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