Children who spend their early years living near overhead power lines are not at greater risk of developing childhood leukemia, according to researchers at the University of Oxford in the UK, who report their findings in the British Journal of Cancer.
Previous research that had included childhood leukemia cases diagnosed between 1962 and 1995 had concluded children living within 600 meters of overhead power lines at the time they were born were at higher risk of developing leukemia.
But in this new study, researchers at Oxford's Childhood Cancer Research Group found no increased risk of leukemia in children born since the 1990s whose mothers lived no more than a kilometer away from overhead power lines when the children were born.
The new study includes nearly 16,500 children diagnosed with leukemia in Britain between 1962 and 2008.
The data came from 53,515 cases in the National Registry of Childhood Tumours, which includes nearly all children diagnosed since 1962 and is estimated to be more than 99% complete for leukemia.
From birth records, the researchers found children born in Britain and matched them to healthy controls, and in each case calculated the distance from the registered mother's address to power lines in England, Wales and Scotland.
No direct biological effect from power lines on risk of childhood leukemia
The authors say this new analysis - which extends the previous study by including 132 kilovolts (kV) as well as 275 and 400 kV power lines, and looks at greater distances from power lines - strongly suggests there is no direct biological effect from power lines and risk of developing childhood leukemia.
Changes in the population characteristics among those living near power lines, or problems with study design, or chance, could explain the previous findings, they say.
"It's very encouraging to see that in recent decades there has been no increased risk of leukemia among children born near overhead power lines," says lead author Kathryn Bunch.
Although more research is needed to find out exactly why the previous study suggested there was a risk before 1980, she says that "parents can be reassured that overhead power lines don't increase their child's risk of leukemia."
Dr. Julie Sharp, who is head of health information at Cancer Research UK, says there has been much concern that living near overhead power lines can raise the risk of cancer - and leukemia in particular - in children, and adds:
"This study is reassuring for anxious parents, as it indicates that overhead power lines don't cause leukemia or other cancers in children."
Medical News Today recently reported on a study by another group of UK researchers, who found childhood leukemia may arise from an infection-fighting process. They proposed that the loss of what they call "fusion genes," combined with a loss of genes required for normal immune cell development, cause leukemia.