Continuing from here (thread expired), new studies suggest that
exposure to radiation after the Chernobyl aacident increases risk
of thyroid cancer in children and adolescents.
In a study of thyroid cancer after the Chornobyl accident in 1986,
researchers at Columbia University's Mailman School of Public
Health report that exposure to radioactive iodine ingested through
the food chain increases the risk of thyroid cancer in children and
adolescents. The study is published in the July 5 issue of the
Journal of the National Cancer Institute.
The 1986 accident at the Chornobyl nuclear power plant exposed
large numbers of people in Belarus, Ukraine, and the Russian
Federation to highly radioactive material. Numerous studies have
shown that exposure to certain types of radiation increases the
risk of thyroid cancer in children and adolescents. However, up
until now, few studies examined the effects of exposure to
radioactive iodines, which can get into the food chain, and only
three studies measured cancer risk from the Chornobyl-related
exposures.
The team of researchers at the M ailman School of Public Health,
with colleagues, screened more than 13,000 people for thyroid
cancer who were under 18 at the time of the Chornobyl accident and
lived in highly contaminated areas of Ukraine. The researchers
estimated each participant's individual radiation dose using
thyroid radioactivity measurements made shortly after the accident
and interview data obtained during screening.
The researchers found 45 cases of thyroid cancer in the screened
group in comparison with the 11.2 cases expected without the
accident. Subjects had a tendency toward lower risk of thyroid
cancer with increasing age at the time of the exposure. The authors
suggest that exposure to radioactive fallout from the Chornobyl
accident increased thyroid cancer risk in those exposed as children
and adolescents.
In young children and adolescents, thyroid gland tissue requires
large amounts of iodine coming primarily from food, said Geoffrey
R. Howe, PhD, professor of epidemiology at the Mailman School and
principal investigator. If radioactive iodine gets into the food
chain, as was the case in Chornobyl, children and adolescents
accumulate large amounts of radioactive iodines in their glands.
This exposes the thyroid tissues to the radiation which in turn,
increases the chance of getting thyroid cancer and other diseases
of the thyroid gland later in life.
The researchers estimate that 75% of the thyroid cancer cases would
have been avoided in the absence of radiation. This estimate
demonstrates a substantial contribution of radioactive iodines to
the excess of thyroid cancer that followed the Chornobyl accident,
observed Dr. Howe.
Full Study here