June 23, 2010 -- Scientists in the U.K. say they can find no association between the risk of early childhood cancers and a mother’s exposure to transmissions from cell phone towers during pregnancy.
Previous reports of apparent cancer clusters near cell phone towers are hard to interpret due to possible biases that could have affected the results, according to researchers led by Paul Elliott, MBBS, PhD, FMedSci, a professor of epidemiology and public health at the Imperial College London.
The researchers say this is the first study to look at cell phone towers, known as base stations, and possible effects.
Use of cellular phones has increased significantly in recent years, raising questions about possible health effects, including brain cancer and other cancers.
Childhood Cancer and Cell Phone Towers
Researchers at Imperial College London examined childhood cancers such as brain tumors to see if they could find a relationship between the diseases and the proximity of pregnant women to cellular base stations.
They analyzed 1,397 British children from birth to age 4 who had been registered in public databases as having been diagnosed with leukemia or a tumor in the brain or central nervous system between 1999 and 2001.
They also studied the location of all base stations across Britain from 1996 to 2001.
Then they estimated:
- Distance in meters of each child’s birth address from the nearest base station.
- Total power output of the facilities within 700 meters of the birth address.
- Power density for each birth address that was within 1,400 meters of the base station.
The researchers found no correlations, though they concede that their focus was on early childhood cancers and did not include longer-term effects or other potential effects on health that have been associated with the use of cell phones.
“The results of our study should help to place any future reports of cancer clusters near mobile phone base stations in a wider public health context,” the researchers write in the study, published on bmj.com.
Public Concern High
John Bithell, DPhil, MA, from the Childhood Cancer Research Group at the University of Oxford, writes in an accompanying editorial that doctors and health care providers should reassure parents not to worry about the proximity of base stations.
“Moving away from a [base station], with all its stresses and costs, cannot be justified on health grounds in the light of current evidence,” Bithel says in a news release.
The researchers write that the number of mobile connections in the U.K. has increased from just under 9 million in 1997 to almost 74 million in 2007, and add that there are more than 4 billion connections worldwide.
Questions have been raised about radio waves causing everything from early childhood cancers to neurological conditions such as migraine headaches and vertigo. Surveys of the public indicate high levels of concern about risks of living near transmission stations.
The mean distance from cellular base stations was 1,107 meters for children diagnosed with brain or central nervous system cancers, leukemia, and non-Hodgkin’s lymphoma, compared with 1,073 meters for well children in a control group.
“To date, there is no convincing or consistent evidence from cellular or animal studies to suggest that exposure to radiofrequency electromagnetic fields is associated with brain tumors or risk of other cancers,” the researchers write. “The few previous reports of excess risks of cancer near mobile phone base stations were based on apparent clusters of small numbers of affected people living nearby.”
But such studies are difficult to evaluate for a variety of reasons, the researchers say.