Power Line-Cancer Link "Slight"

A recent British study has found only tenuous links between childhood cancer and proximity to high-voltage power lines.

In a new study, researchers have found that proximity to power lines may be associated with childhood leukemia - but as previously reported in other studies -- the association remains "slight" and "the relation may be due to chance."

There have been several studies over the years that either support or contradict a relationship between electromagnetic fields and cancer.

The British Medical Journal study, published in June, compared approximately 29,000 cases of cancer (including 9,700 cases of leukemia) diagnosed before age 15 years in the UK with a similar number of cancer-free "controls" matched for gender, date of birth, and birth registration district.

Dr. Gerald J. Draper, at the University of Oxford, and his associates identified subjects living within 1 kilometer of 275 kV and 400 kV overhead power lines.

The team found no association between distance from power lines and overall incidence of cancer. However, children living within 200 meters of a power line had a 69 percent higher risk of leukemia than those who lived more than 600 meters away. Between those two distances, the risk was increased by 23 percent.

"As this is further than can readily be explained by magnetic fields it may be due to other (causative) factors associated with power lines," the group notes.

BMJ science editor Dr. Geoff Watts points out that proposed mechanisms supporting a link between electromagnetic fields and cancer "is at best thin and at worst non-existent."

"Before activists begin blowing up pylons, a bit of perspective might help," he adds. Even if such a link exists, he says, Draper's findings indicate that power lines may be associated with only about five cases of childhood leukemia each year.