Reviews

Fear of frying: power lines and cancer

Those in the media who believe that high voltage power lines and pylons cause cancer in children are like the plucky, armless black knight in Monty Python's Quest for the Holy Grail: they just won't give up.

Last week they thought their Christmases were all about to come at once when they got wind of a report not yet published that was "expected to show" that the power lines were killers. Even better, among the authors of the report was none other than Sir Richard Doll, whose every mention noted that he was the first to show conclusively the link between smoking and lung cancer. These electricity doomsayers were about to be vindicated over their perennial story by the Mike Tyson of epidemiology: if Doll said there was danger, there was no turning back.

Except for one tiny problem-ette. The then unreleased report was not actually going to say that. The UK National Radiological Protection Board (NRPB) review (www.nrpb.org.uk/Absd12-1.htm) published on 6 March concluded: "There is . . . some epidemiological evidence that prolonged exposure to higher levels of power frequency magnetic fields is associated with a small risk of leukaemia in children. In practice, such levels of exposure are seldom encountered by the general public . . . the epidemiological evidence is currently not strong enough to justify a firm conclusion that such fields cause leukaemia in children."

And how small was this "small risk"? The NRPB estimated that in the United Kingdom the additional risk from power lines meant an extra case of childhood leukaemia every two years, an increase in the annual risk in all UK children from about 1 in 20 000 to 1 in 10 000. In children highly exposed, this would mean an increase from 1 in 1400 to 1 in 700.

So how did the media handle it? On 4 March the Sunday Times carried the front page headline "Pylons are cancer riskofficial." Britain's Independent Television News thumped its dictionary of quantification rhetoric and came up with the headline "Pylon report reveals 100 000 at risk." On different days the BBC's web page ran "Fresh pylon link to child cancer" and "Watchdog confirms pylon cancer link." The Sydney Morning Herald carried the story three days in a row: "First official link between power lines and cancer," "Cancer and powerlines: painful questions return with the grief," and "Powerlines double cancer risk."

Although the NRPB report noted "it has not been possible to detect this increase in the UK," some journalists and headline subeditors were not fussed by this and used the theoretical estimates to talk dramatically about a "doubling" of the risk.

Other publications played it down, doubtless, if you asked the doomsayers, fresh from secret deals done between their advertising departments and the electricity industry. In the United States the New York Post said "Leukemia link to power lines minimal," the Irish Times said "Report discounts cancer risk from pylons," and the Guardian noted "Leukaemia study finds unexplained home radiation," focusing on the idea that electrical fields in ordinary homes might actually pose greater risk than evil high voltage pylons.

Interviewed by Angela Catterns on Sydney radio on 7 March, Doll was asked, "Can we extrapolate that there is indeed a link between power lines and cancer?" Doll replied firmly, "No we can't, and that is one of the things we say very clearlythat you cannot conclude this. . . . That was a report in a newspaper that is not known for the reliability of its scientific reporting. It's not what we said."

Speculative and alarmist reporting is bad enough, but the consequences can be more serious. Cancer agencies in Australia have received many calls from anxious people wanting to know if they should sell their house or have their children "tested." Land and house values may fall around power lines, causing financial grief to perhaps thousands. One angry man cancelled his regular donation, saying that the cancer council had neglected this important issue. Enter "power lines radiation and cancer" in a web search engine, and you can put the kettle on waiting for hundreds of sites to downloadall with the same message, that power lines are killing our children. Any scientist who so much as nods in the direction of agreeing with this is a heroic whistleblower, and inconclusive results simply mean scientists aren't looking hard enough to find what we all know to be the case.

Professor D'Arcy Holman from the University of Western Australia calculated that, even assuming a worst case scenario, the UK projections would mean that in Western Australia there would be three extra cases and one extra death from childhood leukaemia every 50 years. By comparison, there are an estimated three childhood deaths every year in the state from asthma and lower respiratory illness caused by passive smoking and about 10 childhood deaths every year from drowning, including those in unfenced residential pools. Would that these could get such headlines.

Simon Chapman, professor of public health. 

University of Sydney, Australia