| Biomonitoring
WHAT
IS BIOMONITORING? | HOW
DOES IT WORK? | NATIONAL
EXPOSURE REPORT | COMPARE
TO MONITORING AND TRACKING
What
is Biomonitoring?
Biomonitoring
is the laboratory analysis of blood, urine, serum, saliva
and other body fluids for the purpose of identifying the
burden of certain chemicals present in the human body. Biomonitoring
allows us to recognize the populations that are exposed
to and affected by chemicals in the environment. When combined
with a nationwide system for tracking chronic diseases,
biomonitoring can provide the information necessary for
public health departments, health care providers, and policymakers
to identify and address public health threats.
How
Does Biomonitoring Currently Take Place?
The
Centers for Disease Control and Prevention (CDC) currently
conducts its biomonitoring program through the National
Health and Nutrition Examination Survey (NHANES). NHANES
is an annual, cross-sectional, representative survey designed
to collect information about the health and diet of the
civilian, non-institutionalized population of the United
States. NHANES samples about 5,000 people every year through
a Mobile Examination Center, staffed by medical professionals,
which travels around the country to randomly selected households,
conducting both interviews and physical exams.
In 1999, 27 chemicals were added to the NHANES examination,
providing information on the magnitude and extent of population
exposure to built or natural environmental contaminants
in air, water, soil and food. This biomonitoring, although
limited, provided the information for the first National
Report on Human Exposure to Environmental Chemicals, published
by the CDC in 2001. The report can be accessed at www.cdc.gov/nceh/dls/report.
CDC aims to expand the number of chemicals covered by the
NHANES exam to about 100 over the next few years.
The
National Exposure Report: Understanding the relationship
between chemicals and the human body
The
publication of the National Report on Human Exposure to
Environmental Chemicals is an important step towards establishing
the link between the environment and chronic disease. However,
it remains a "snapshot" of the American public's exposure
to some common pollutants in the environment. It is important
to recognize that information gathered on chemicals in the
human body, such as the data provided by CDC's biomonitoring
study, is only one piece of the puzzle. There are many chemicals
for which we have little or no information regarding long-term
chronic health effects. The nation still has an incomplete
picture of the types and levels of various chemical contaminants
in our food, water and air. Therefore, we need to learn
much more about the chemicals in our surrounding environment
and how they are metabolized or stored by the human body,
or how they interact in conjunction with food items, medications,
prescribed or over the counter. This information is important
for all Americans, but of particular importance to those
populations who may be particularly vulnerable to the effects
of certain chemicals. These include infants, young children
and pregnant women.
Furthermore, the NHANES study is burdened by limitations
that include:
-
A
limited set of pollutants: in 1999 it was only 27;
-
Limited
geographic coverage: in 1999 NHANES was conducted in
only 12 locations across the country; there is not enough
data to make conclusions about environmental exposures
on state or local levels;
-
Initial
funding that was inadequate to complete the analysis
of findings and make data available to researchers,
policymakers, and the public; and
-
Lack
of association with ongoing health surveillance that
could link human exposures to known environmental hazards.
How
Does Biomonitoring Relate to a Chronic Disease Monitoring
and Tracking Network?
Biomonitoring
constitutes an important part of the nationwide chronic
disease monitoring and tracking system needed by the United
States. It may confirm that an exposure has occurred and
caused illness. The current disease registries for cancers
and birth defects are important and must be expanded and
linked to such national tracking system. The data obtained
must be overlaid with current hazard tracking done by the
EPA and the clinical tracking of incidence and prevalence
of chronic diseases and conditions. In addition, further
characterization of the affected population in terms of
other population-based determinants can serve to inform
public health officials, clinicians, industry and public
officials. Such an integration of information can provide
the best possible answer on whether communities are suffering
illness that may be attributable to environmental toxins.
Only when all this information is complete can we systematically
identify and analyze the relationships between human exposure
to environmental hazards in a particular area, the toxins
found in the bodies of those who live there, and the incidence
and prevalence of certain diseases and conditions in that
same population.
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