Low-level magnetic fields concern

[Guest guest]

Low-level magnetic fields concern

 

By Dr David Whitehouse

BBC News Online science editor

 

http://news.bbc.co.uk/2/hi/science/nature/3506713.stm

 

Exposed brain cells release damaged DNA

Exposure to low-level magnetic fields could be harmful, say US scientists.

Rats exposed to magnetic fields similar to those humans encounter developed

damage to the DNA in their brain cells.

 

Professor Henry Lai, of Washington University, said that people should be

prudent in their use of electrical devices held close to the head.

 

The peer-reviewed study is published in Environmental Health Perspectives, a

journal of the US National Institute of Environmental Sciences.

 

Duration can be damaging

 

The researchers discovered that rats exposed to a weak magnetic field

oscillating 60 times per second for 24 hours showed DNA damage to their

brain cells. Rats exposed for 48 hours showed even more damage.

 

They also say that the exposure resulted in an increase in brain cell

" apoptosis " or " cell suicide " - a process in which the cell self-destructs

because it cannot repair itself.

 

But what are the implications for people and the magnetic fields most of us

encounter in our daily lives?

 

 

Unexposed rats brain cells do not

Speaking to BBC News Online Professor Lai said that, in his opinion,

prolonged exposure to low-level magnetic fields, such as those emitted by

hair dryers, electric blankets and razors could damage human brain cells.

 

" We do not use hair dryers or electric razors for more than a few minutes

each day. However, the exposure to magnetic fields from these devices, held

close to the head, is quite high, " he says.

 

" Our important result is that in rats the harmful effect accumulates over

time. The big question is, if we use a hair dryer for five minutes a day

will the harmful effect accumulate in humans? We do not know. "

 

" But our results raise the possibility that it might. "

 

Lai says that people should be cautious and limit their exposure as much as

possible.

 

In the summary of the reseach paper he and co-worker Narendra Singh says

their work could, " ...have an important implication on the possible health

effects associated with exposure to extremely-low frequency magnetic fields

in the public and occupational environments " .

 

'Noteworthy' study

 

A spokesman for the UK's National Radiological Protection Board described

Professor Lai's study as, " Interesting. Work of this sort is noteworthy " .

 

" The research will need to be replicated to see if it is a significant

effect. If it led to a real health effect we would have expected to have

seen it in behavioural studies of rats exposed to stronger magnetic fields

for longer periods. So far we have not. "

 

" What Professor Lai may have seen is a biological effect, " the spokesman

said, " It remains to be seen if that will be translated into a real health

effect " .

 

The NRPB advisory group has already noted a weak association between the

incidence of childhood leukaemia and exposure to elevated magnetic fields.

 

The association is not observed in the UK, but has been seen in the USA and

Sweden.

 

One possible reason for this difference is because the USA uses a 110-volt

electricity system, which confers a higher exposure to residual magnetic

fields than the 240-volt system used in the UK and mainland Europe.