Frequent use of mobile phones and other cordless telephones have a biological effect on the brain, suggests a study, which recommended caution in the use of these phones, above all among children and adolescents.
The study at Orebro University in Sweden examined the use of wireless telephones among children and adolescents and whether adolescents themselves perceive any health problems that might be related to this use.
Medical researcher Fredrik Soderqvist also studied blood samples from adults, looking at two so-called biomarkers to see the biological effect of the use of phone on the brain.
"Children may be more sensitive than adults to radiation from wireless phones," said Soderqvist, who will present his findings at the Swedish university.
One of these studies focused on a protein that exists in the so-called blood-cerebrospinal-fluid barrier, which is part of the brain's protection against outside influences.
The study, reported by the Science Daily online, revealed an association between use of wireless telephony and increased content of the protein transthyretin in the blood.
Soderqvist underlined that the increase as such does not have to be a cause of concern, but since it indicates that the brain is in fact affected by microwaves from wireless telephones, there may be other - as yet unknown - effects that may impact our health.
"The connection was strongest regarding headaches, asthmatic complaints, and impaired concentration. But more research is needed to exclude the effects of other factors and sources of error, even though it is difficult to see how it could be fully explained by such factors," he said.