LENGTH: 536 words
Even Vietnam veterans who were not involved in spraying Agent
Orange experienced higher levels of dioxin contamination, which
is linked to an increased overall risk of cancer, reports a new
study.
The study, conducted by a group of U.S. Air Force and other researchers,
analyzed cancer rates among nearly 1500 Air Force veterans who
served in Southeast Asia during the Vietnam War, but did not actually
spray Agent Orange or other herbicides. The men served as a comparison
group in a previous study of cancer risk in veterans of Operation
Ranch Hand, the unit responsible for spraying Agent Orange.
Even though they didn't work with Agent Orange, veterans in the
comparison group had significant blood levels of TCDD, the highly
toxic dioxin contaminant of Agent Orange. The current study was
designed to assess whether low-level exposure to TCDD affected
the later risk of developing cancer.
Higher blood levels of TCDD were associated with higher rates
of cancer in the years after serving in Southeast Asia. For veterans
with blood TCDD levels above the median, cancer risk was 60% higher
than for veterans with lower levels. The increased risk wasn't
limited to any specific type of cancer, although much of it was
related to digestive and respiratory cancers and of the skin cancer
melanoma.
The findings were published in the
Journal of Occupational and Environmental Medicine.
The study also looked at how length of service in Southeast Asia
affected cancer risk. Veterans whose time in Southeast Asia was
above the median were more than twice as likely to develop prostate
cancer, compared to those with shorter tours of duty. Prostate
cancer risk was unrelated to TCDD level.
There was also a significant interaction between duration of
service and dioxin contamination - veterans who served longer
in Southeast Asia tended to have higher blood levels of TCDD.
Cancer risk was highest for vets who spent more than 2 years in
Southeast Asia and had TCDD levels above the median.
TCDD and other dioxins have been linked to cancer and a wide
range of other health problems. A recent study found increased
rates of cancer - specifically prostate cancer and melanoma -
in Air Force veterans who sprayed Agent Orange during the Vietnam
War. That study also suggested possible increases in cancer risk
in the comparison group of Air Force veterans who served in Southeast
Asia but did not spray Agent Orange.
The new results support the finding of increased cancer rates
for veterans with higher TCDD levels, even though they weren't
directly exposed to Agent Orange. TCDD may promote the development
of cancer even at very low levels of exposure. Another possible
explanation is that blood TCDD levels reflect some other, unknown
risk factor.
The interaction between cancer risk, TCDD levels and time served
in Southeast Asia suggests that a combination of factors are involved.
More research will be needed, including longer follow-up of Vietnam-era
veterans and more detailed information on their individual tours
of duty in Southeast Asia.
This article was prepared by Obesity, Fitness & Wellness
Week editors from staff and other reports.
Copyright 2005, Obesity, Fitness & Wellness Week via
NewsRx.com.
|