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The Incidence of Nonrespiratory Cancers And Exposure to Asbe
Research has shown a clear link between exposure to asbestos and respiratory cancers (cancer of the lungs and mesothelioma) in humans. However, the link between exposure to asbestos and other types of cancers is less clear.
Some epidemiologic studies s
By: U. S. Govt.
Introduction
Medical research has shown that people who are
exposed to asbestos (through breathing in the asbestos
fibers) have an increased risk of developing
respiratory cancers such as lung cancer and
mesothelioma (a rare form of lung cancer).
Some research suggests that exposure to asbestos also
increases the risk of nonrespiratory cancers. However,
despite a few studies reporting these associations, most
studies do not show a consistent relationship between
asbestos exposure and nonrespiratory cancers.
Following is an overview of studies on asbestos
exposure and nonrespiratory cancers.
Gastrointestinal and Colorectal
Cancers
Studies of asbestos workers suggest that asbestos
exposure might be associated with gastrointestinal
(esophagus and stomach) and colorectal (colon and
rectum) cancers. However, the evidence is unclear.
These studies showed small increases in the number of
deaths from gastrointestinal and colorectal cancers. For
example, among 17,800 insulation workers, 99 people
died from these cancers, even though the rate in the
general population is expected to be 59.4 deaths.
Among 2,500 asbestos textile workers, 26 people died
from these cancers, but 17.1 deaths were expected.
Several other studies have shown similar patterns.
However, other mortality studies of asbestos workers
found no significantly increased risk for gastrointestinal
or colorectal cancers. Other reviewers found no causal
relationship between workers' exposure to asbestos
and gastrointestinal cancer.
Some evidence shows that short-term (acute) oral
exposure to asbestos might bring on precursor lesions
of colon cancer, and that long-term (chronic) oral
exposure might increase the incidence of
gastrointestinal tumors.
Most epidemiologic studies to see if cancer incidence is
higher than expected in places with high levels of
asbestos in drinking water detected increases in cancer
deaths or incidence rates at one or more tissue sites
(mostly in the gastrointestinal tract).
Some of these increases were statistically significant.
However, the magnitudes of increases in cancer
incidence tended to be rather small and might be
related to other risk factors such as smoking. Also,
these studies were conducted on worker populations,
with generally higher exposures; still, only small and
inconsistent elevations have been reported.
There is relatively little consistency in the observed
increases across studies.
Kidney, Brain, Bladder, Laryngeal,
and Other Cancers
Results of studies of cancers at other sites are also
inconclusive. One reason is that relatively few st....[MORE]
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