Testimony
Before the Senate
Subcommittee on Public Health, Committee on Health, Education,
Labor, and Pensions
ATSDR's
Role in Environmental Health Tracking
Statement
of
Henry
Falk, M.D., M.P.H.
Assistant
Administrator,
Agency
for Toxic Substances and Disease Registry
For Release
on Delivery
Expected
at 10:00am
on
Wednesday, March 6, 2002
I am Dr. Henry Falk, Assistant Administrator
of the Agency for Toxic Substances and Disease Registry
(ATSDR). ATSDR is a sister agency to the Centers for Disease
Control and Prevention (CDC). Congress created ATSDR in
the Superfund legislation to assess the public health
impact of Superfund sites to nearby populations, and to
determine the relationship between exposures to hazardous
substances and disease.
ATSDR has the specific legislative
authority to develop and maintain a national registry
of serious diseases and illnesses of persons exposed to
toxic substances.
Over the past twenty years we have
been working to recognize disease patterns in relation
to possible toxic exposures from Superfund sites. Through
our toxicological and chemical exposure programs, as well
as epidemiologic studies, we have made considerable progress
in assessing the association between exposure and health
effects for many individual chemicals - and for many chemical
mixtures - although much work remains to be done.
This experience is one of a number
of factors that uniquely position ATSDR to work with the
CDC on the planning and implementation of a joint Environmental
Public Health Tracking Network.
Another strong component of the ATSDR
program that will be of critical importance to an environmental
public health tracking network is our Geographic Information
System (GIS) capability. ATSDR routinely uses GIS mapping
as a tool to help illustrate plumes of exposures from
available environmental data overlaid with demographic
data for the surrounding population (particularly vulnerable
groups such as young children, the elderly or pregnant
women). This not only enables the health professionals
who are assessing the possible health problems resulting
from such exposures to better see what they are dealing
with - but also gives community members a picture of their
possible exposures.
ATSDR has expanded its use of GIS
to help with epidemiologic studies and with emergency
planning. We are incorporating as many databases as possible,
including data from the Environmental Protection Agency's
(EPA) Toxic Release Inventory, national hospital data,
and others.
GIS mapping will serve as an important
tool for the eventual environmental public health tracking
network allowing us to overlay graphically environmental
data with health disease patterns data. This can literally
give us a picture of possible associations between environmental
exposures and disease at a very local geographic level
such as a zip code area or census tract.
A good example of ATSDR's work linking
environmental exposure to disease using the latest technologies
is our health study in Toms River, New Jersey. Working
with the New Jersey Department of Health and Senior Services
(NJDHSS), ATSDR confirmed that the overall childhood cancer
incidence rate in Dover Township was statistically significantly
elevated for the period of 1979 through 1995. This increased
rate was primarily due to excesses of leukemia and brain/central
nervous system cancer in females residing in the Toms
River section of Dover Township. Working closely with
the community and the NJDHSS, we jointly designed a study
to test the hypothesis that the childhood cancers were
associated with environmental exposure pathways identified
in earlier reports - namely water (in wells) and air.
ATSDR conducted sophisticated modeling
of the water distribution system that mapped the percentage
of water that each household received from each well field
on a monthly basis. That mapping was done for the entire
time frame of 1962 through 1996. Using ATSDR funding,
NJDHSS conducted a case-control epidemiologic study made
up of two parts - an interview study and a birth records
study. Though the sample size was small in the study,
they found an association between prenatal exposures to
a particular well field in the years 1982-1996 and leukemia
in female children of all ages. At
only a very few other sites has an association between
an environmental pathway and a cancer cluster been documented.
For this reason - the findings of the Toms River study
are especially important.
The water modeling that was done applied
new, emerging technologies to address the concerns in
this community. Using the new technology of GIS, we can
for the first time start linking all existing, geocoded
data bases together. Linking disease data from cancer
registries, Behavioral Risk Factor Surveillance System
(BRFSS), or blood lead levels to EPA's Toxic Release Inventory
or air quality data could provide important new insights
to possible linkages between exposures and disease.
CDC and ATSDR have key surveillance
systems in place in a limited number of states. CDC's
national birth defects registry program is currently in
35 states, and CDC is working with 37 asthma surveillance
projects; while ATSDR's Hazardous Substances Emergency
Event Surveillance (HSEES) system is in 16 states. These
tracking systems are important to identify not only national
rates of disease, but even more importantly clusters of
disease which may be caused by environmental factors we
can ameliorate.
We also should develop new tracking
of diseases thought to have some relationship to environmental
exposures. For example, currently no tracking exists for
critical neurologic diseases such as multiple sclerosis
or Parkinson's, nor immune system diseases such as lupus
and other autoimmune diseases, nor developmental diseases
such as autism or other neurodevelopmental
diseases. Nor do any tracking systems exist for diseases
known to be caused by exposure to specific hazardous substances
like asbestos.
ATSDR has begun to address one of
these diseases - multiple sclerosis (MS) - around multiple
Superfund sites. In an article just published in Neurology,
ATSDR researchers found nationally a 50% increase
in MS in women for the period of 1991 - 1994, versus an
earlier time period of 1982 - 1986. To address local concerns,
ATSDR in cooperation with state and local public health
partners, has initiated a number of studies. In El Paso,
Texas a cluster of MS cases was investigated. Based on
available background estimates, preliminary results show
the number of MS cases among former students at one school
to be twice as high as expected. In another effort, we
are funding programs in Ohio, Missouri and Texas to investigate
MS prevalence rates in Lorain County, Ohio; Independence
and Sugar Creek, Missouri; and a 19-county area around
Lubbock, Texas. These studies will use neurologists' medical
records as the primary data source to determine age- and
sex- specific MS prevalence rates in these areas. ATSDR
conducts these efforts through a cooperative agreement
program, and has established such relationships with more
than 30 state health departments.
Exposure to asbestos clearly causes
disease of the lungs. In a medical screening program of
more than 6,000 people that ATSDR conducted from July-November,
2000 in Libby, Montana, more than 18% of the population
were found to have lung abnormalities. Former workers
from W. R. Grace had an even higher incidence of disease
- 48%. These abnormalities were associated with exposure
to tremolite asbestos. Had a tracking system been in place
we would have found these cases much earlier. But, even
if established now, much good can be done. Under its registry
authority, ATSDR is planning to establish a registry for
former workers and families at Libby to track people over
time, find new cases earlier and assist in referring patients
for timely medical treatment. We also are currently assisting
the New York City Department of Health and CDC in developing
a conceptual framework for a registry of workers and residents
in lower Manhattan in the wake of the World Trade Center
disaster.
If we are ever to determine the nature
and extent of environmental causes for these diseases,
it is important that we initiate tracking programs for
each of them, and build them into an integrated data system.
Working with the states and other stakeholders, CDC and
ATSDR believe we can implement an effective and viable
system nationwide that can make the Pew Commission's vision
a reality.
Madame Chairman, this concludes my
testimony. I would be happy to answer any questions.
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Last
revised: March 6, 2002