RE: Down Syndrome and Radiation Exposure

["Franta, Jaroslav" <frantaj@aecl.ca>]

> Bernard L Cohen[SMTP:blc+@pitt.edu] wrote on Friday, June 11, 1999 9:49 AM
> 
> 	Down Syndrome could be caused by high radiation doses degrading
> the immune system, availability of repair enzymes, or other biological
> defense mechanisms. There is excellent evidence that high level radiation
> causes cancer and genetic effects by degrading these biological defense
> mechanisms, and that radiation initiating aberrations is a minor effect.
> 
> On Thu, 10 Jun 1999, Karam, Andrew wrote:
> 
> > I believe that Down Syndrome is caused by having three copies of
> Chromosome
> > #21.  I do not see how this can be considered an effect of radiation
> > exposure.  
> > 
> > According to my genetics text, it is caused by "...nondisjunction of
> > chromosome 21 during meiosis...Following fertilization with a normal
> gamete,
> > the trisomic condition is created."
> > 
<><><><><><><><><>

FYI, this BBC posting at
http://news.bbc.co.uk/hi/english/health/newsid_380000/380274.stm

...includes a little blurb on Down Syndrome:

> Tuesday, June 29, 1999 Published at 00:31 GMT 01:31 UK 
BBC  <<...>> Health
>  <<...>> Flights radiation warning 
> People who fly frequently are not being made fully aware of the potential
> dangers of exposure to radiation on flights, specialists say. 
> Frequent flyers on transatlantic flights are exposed to the equivalent of
> 170 chest X-rays a year, putting them at increased risk of cancer,
> according to the US Federal Aviation Administration. 
> The law ensures that people who work in hospital X-ray units and nuclear
> plants are get as much protection as possible from exposure to radiation,
> but there are no similar laws applying to the risk from air travel. 
> The European Commission is currently examining the issue, and from May
> 2000 airlines will have to measure radiation levels on flights. 
> Tackling the issue 
> Specialists from government bodies, the health service and industry will
> discuss the problems at a one-day seminar on cosmic radiation organised by
> the Aviation Health Institute. 
> The National Radiological Protection Board (NRPB) says that aircrews are
> exposed to 4.6 millisieverts (mSv) each year, compared to nuclear workers
> who are exposed to 3.6mSv. 
> Cosmic radiation from the sun gets stronger at higher altitudes because
> the atmosphere thins out and is less able to offer protection from the
> rays. 
> Different types of plane fly at different altitudes - 737 jumbo jets, for
> example, cruise at 37,000 feet while Concorde goes to 60,000. 
> Although the danger posed on a single flight is insignificant, repeated
> exposure does appear to increase the risk of cancer. 
> Nine studies in North America and Europe have shown increased rates of
> cancer among those who work in aeroplanes. 
> Pilots are more likely to get colon, rectal, prostate and brain cancers,
> while flight attendants are twice as likely to suffer breast cancer. 
> Aircrew members who are pregnant could also be putting their unborn
> children at risk of diseases such as Down's syndrome and leukaemia. 
> Low risk for casual flyer 
> The general public is at little risk because they are unlikely to make
> enough journeys at a high enough altitude to suffer high exposure over
> time. 
> However, there is some concern over the effect on couriers or businessmen
> who may fly regularly. 
> Executives are also likely to fly regularly in private jets, which fly at
> around 43,000 feet. 
> There is currently no legislation addressing exposure to radiation through
> air travel, although a European Commission directive could change that. 
> The Euratom directive will require European airlines to measure levels of
> radiation on flights. 
> The information will be used to assess the risk of cancer and birth
> defects, and will include about 80,000 people. The earlier studies
> involved about 5,000 to 10,000. 
> 'Companies should be aware' 
> Farrol Khan, director of the Aviation Health Institute, said companies who
> sent employees on regular trips by plane should be aware of the risks and
> inform their staff accordingly. 
> "Otherwise, this could become litigation in the future if you knew there
> is a problem and you didn't tell your employees about it," he said. 
> "Then six years later they end up with cancers, and they say 'ah, but you
> knew there was a risk six years ago, why didn't you tell us? We're going
> to sue you'." 
> Patrick Slomski, an aviation lawyer who will address the seminar, said
> better information was better for all parties. 
> "This may help forestall litigation that is clearly undesirable for the
> airline or its customers." 
> Dr Michael Clark of the NRPB said it may be possible that certain cancers
> were more likely among aircrews, but on the whole their health was good. 
> He said: "As far as I understand it, aircrews are actually healthier than
> the general public, because to be selected as a pilot or a flight
> attendant you have to go through a health check. 
> "After that you have regular check-ups, so you may get the healthy worker
> effect." 
> 
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