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What is GIS?
A Geographic Information System (GIS) is a computerized database that
can be used to store, analyze, and display data, particularly data associated
with locations on a map. It is a powerful tool for research when a combination
of geographic information is involved, as in health studies.
We can display the data stored in the GIS as maps, tables, and charts.
Silent Spring Institute researchers can create complex maps by combining
multiple layers of data similar to overlaying transparencies. For example,
locations of drinking water sources can be layered on land use data and
information on groundwater flow to identify areas where land use could
potentially affect drinking water. We can use the GIS to study changes
over time and use these analyses to investigate the relationships between
environmental factors and cancer incidence.
What information is used in
Silent Spring Institute's GIS?
Examples of data used in the GIS include:
· Base map data such as locations of roads, town boundaries, lakes, and
rivers.
· Land use data, such as the locations of residences, commercial and industrial
developments, open space, agriculture, military installations, and airports.
· Specific data for health studies incorporating such information as census
data, geographic distribution of disease, results of laboratory tests of environmental
samples, locations of hazardous waste sites, or areas of known pesticide use.
How is the GIS used in Silent Spring
Institute's Cape Cod Breast Cancer and Environment Study?
Pesticides have been widely used on Cape Cod for many decades. For the Cape
Cod Breast Cancer and Environment Study, Silent Spring Institute
researchers located and compiled Cape pesticide data from 1940-1990.
Efforts were made to include the geographic area sprayed, the time period
during which it was sprayed, and the type of pesticide that was used
and its active ingredients. Other data, like the location of former cranberry
bogs where pesticides would have been used, were re-created using land-use
maps from 1951-1990. The GIS was used to show the locations of chemical
pesticide use, and when they were applied, for each town on the Cape.
This information will be used with the residential history of women who
have participated in the Cape Cod Study to identify their exposure to
chemicals over their time spent living on the Cape.
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Where
do we get the information used in the GIS?
The data about the Cape's environment used in Silent Spring Institute's
research includes information from the Cape Cod Commission, Cape municipalities,
and MassGIS at the Executive Office of Environmental Affairs, as well as
data on private wells, pollution discharge sites, hazardous waste sites,
and water distribution pipes and plumes.
Can the public have access to this
information?
The research in which the GIS has been used is reported to the Massachusetts
Department of Public Health and is eventually published in scientific
journals. The findings are also reported to the residents of Cape Cod
and the press. All analyses shown in public forums use aggregate data:
No individual name or personal identifying information is ever published
or publicly displayed in the GIS.
Is the GIS and the information it
uses only of benefit to breast cancer research?
Silent Spring Institute has collected and organized extensive data about
the Cape's environment that we anticipate will be useful for other studies
of health issues on the Cape.
I have breast cancer. Should I be
worried that my personal information
will be made public to everyone in the GIS maps?
As part of its study design, Silent Spring Institute stipulated it would
maintain data in accordance with stringent requirements that ensure confidentiality
of the individuals involved in the study. No information that can identify
individuals or the locations of their households will ever be displayed
in publications or viewed at a public forum. The information will also
be kept safe from unauthorized computer access. Only selected members
of the study team - each of whom is required to keep the information
confidential - will be allowed electronic access to this data.
How did you get information
about me in the first place?
By legal statute, physicians and other health care providers must report
cases of certain diseases, known as reportable and notifiable diseases,
to health authorities. The specific diseases that must be reported vary
by state. In Massachusetts, cancer registries must report new cancer
cases to the Massachusetts Cancer Registry in the Massachusetts Department
of Public Health. Because our study satisfied the state's rigorous application
and review process, researchers at Silent Spring Institute obtained information
on possible participants from the Massachusetts Department of Public
Health.
In addition to collecting diagnostic information about cancer, the registry
collects demographic information such as the address, date of birth,
nationality, occupational history, smoking history, and vital status
for most cases reported to them. The state maintains these records in
order to track rates of diseases and to facilitate studies about diseases
in the state. The registry keeps this information strictly confidential.
To use these data in its study, Silent Spring Institute agreed to maintain
these data in accordance with stringent requirements that ensure confidentiality
of all participants.
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