I was interested to hear, on the early morning news today, of a
definitive study about childhood leukaemia and its incidence related to
living in proximity to overhead power lines. My colleagues in the power
industries have laboured long over similar articles and hypotheses.
Naturally, I was soon reading the actual article in the BMJ. I must
assume that the statistical methodology is suitable but there was one
more obvious correlation which sppears to have been completely
disregarded.
The relative risks for disease groups at varying distance from the
power lines are itemised. I concur that there may be a higher relative
risk for childhood leukaemia. More obvious to me were the relative risks
of CNS/Brain tumours which appear to have considerably lower relative
risks the nearer one lives to the transmission cables. Does this imply
that there is a positively beneficial effect for the prevention of these
illnesses or is this also a result of "chance" or "confounding"?
Whilst the estimated figure of 5 extra deaths from leukaemia is of
concern and sufficient to undertake further study and action is it not
also important to mention to the many thousands of worried parents who
live in these areas that there may be a reduction in the incidence of
other childhood cancers. Perhaps a figure of the number of deaths
prevented by this apparent advantageous effect, and in line with the
statistical methods applied for leukaemia, should also be calculated and
if it is more than 5 then maybe we should take more care before worrying a
generally uninformed public with "horror" headlines.
Rapid Response:
Danger of Power Lines
3 June 2005
Sirs
I was interested to hear, on the early morning news today, of a
definitive study about childhood leukaemia and its incidence related to
living in proximity to overhead power lines. My colleagues in the power
industries have laboured long over similar articles and hypotheses.
Naturally, I was soon reading the actual article in the BMJ. I must
assume that the statistical methodology is suitable but there was one
more obvious correlation which sppears to have been completely
disregarded.
The relative risks for disease groups at varying distance from the
power lines are itemised. I concur that there may be a higher relative
risk for childhood leukaemia. More obvious to me were the relative risks
of CNS/Brain tumours which appear to have considerably lower relative
risks the nearer one lives to the transmission cables. Does this imply
that there is a positively beneficial effect for the prevention of these
illnesses or is this also a result of "chance" or "confounding"?
Whilst the estimated figure of 5 extra deaths from leukaemia is of
concern and sufficient to undertake further study and action is it not
also important to mention to the many thousands of worried parents who
live in these areas that there may be a reduction in the incidence of
other childhood cancers. Perhaps a figure of the number of deaths
prevented by this apparent advantageous effect, and in line with the
statistical methods applied for leukaemia, should also be calculated and
if it is more than 5 then maybe we should take more care before worrying a
generally uninformed public with "horror" headlines.
Sincerely
Dr John Burgess
Competing interests:
None declared
Competing interests: No competing interests