BBC Radio 4 "Costing the Earth" programme, Thursday 21st September 2000, 21:00 hrs BST examined the ongoing work at Bristol University, including the new preliminary epidemiological evidence of cancer increases near to powerlines that was announced at this year's Bioloelectromagnetics Society Meeting that was held in Europe this summer. Despite the increasingly frenzied statements coming from Dr John Swanson, an employed spokesman of National Grid, that high voltage powerlines are safe (he has been writing unsolicited letters to periodicals like Farmers' Weekly), Dr Alan Preece and colleagues announced some dramatic new evidence showing a significant cancer effect linked to high voltage powerlines.

Looking for epidemiological evidence to support (or not) Professor Denis Henshaw's corona ion and aerosol theories, Preece, et al, analysed the whole of the UK SW Cancer Registry database containing details of over 10,000 cancer cases, and separating their addresses into their location with respect to 132 kV and above power lines. These were then normalised for population density and other factors. They found a very significant increase in lung cancers, and increases in other pollutant linked cancers, up to over 500 metres DOWNWIND of the line compared with upwind of lines, and skin cancers close to the lines. This is work that is very much in progress and efforts are being made to sort out any possible effects of confounders (smoking, age, social status, etc), although the statistics are looking strong.

Here we have (i) a plausible theory, (ii) laboratory testing of the Henshaw and Fews theory published a few years ago (and the possible health implications dismissed by the UK NRPB), (iii) a further two papers by Fews, Henshaw et al (I.J.R.B.1999, Vol75, No12, pp1505-1521 & pp1523-1531), showing real, measured, pollutant aerosol and corona ion effects near high voltage powerlines that could have large public health implications (again dismissed by the NRPB and National Grid plc), and now (iv) large scale epidemiological (public health) evidence of elevated cancer risk under and downwinf of high voltage power lines, but not upwind!  This gives enormous support for the Fews, Henshaw, et al, theories. We have known and accepted pollutant mechanisims for carcinogenesis that are increased by the presence of high electric fields, and now we have public health records evidence that supports them!

This is DRAMATIC epidemiological support for Henshaw's theories, which MUST now be tested by all future studies, ideally including the UK Childhood Cancer Study. The UKCCS have the full postcode of all the cases and controls and also the digital database mapping locations of the power lines, so it should be relatively easy to do. To date, they have refused to add this analysis to their data as they have so few cases and control near to HV power lines. In fact, they have 50 cases and 45 controls within 400 m of 275 and 400 kV lines, and 25 cases and 24 controls within 200 metres of 132 kV lines, so it would not be a great deal of work to manually test this data to see if it supports (or not) the Fews, Henshaw, et al theories.

The Fews, Henshaw et al theories fit well with the Northampton childhood cancer cluster in Pembroke Road. The house backed on to a railway marshalling yard with many 25,000 volt overhead wires, and the tracks nearest to the houses fed a petrochemical depot. So they had petrochemical aerosols and high electric fields ... and ... a fatal cluster of childhood cancer cases along the road backing on to the railway.

The Fews & Henshaw theories may not be correct ~ but they are the most likely theories to surface so far and they are looking stronger and stronger as time passes.   All developed countries should now analyse their cancers to test the Bristol theories to see if they fit the exposure conditions and public health outcomes.