Danish cellphone study shows no cancer link

But the study did not clear cellphones of other healthrisks, senior researcher Dr Christoffer Johansen told Reuters.

"We have only addressed the cancer question," he said. "Wecannot exclude that long exposure to mobile phones can cause ringing noises in the head, migraine, headaches and other symptoms of the central nervous system."

Diseases like Parkinson’s, Alzheimer’s and various types ofdementia and nervous complaints might also be associated with mobile phones, as well as skin diseases at points where the device comes into contact with users’ flesh, he added.

Johansen said such a big study could only be carried out inScandinavia where a system of compulsory registration of citizens operated and cancer registers dated back to World War Two.

FIRST SURVEY OF ITS KIND

"Our study is the first nationwide, population-basedanalysis of its kind. It is important because the link-up of information from different administrative systems could simply not be done in other countries," Johansen said.

Data on 420,095 users identified from Danish mobile phoneoperators’ subscriber lists were linked to information from the Danish Cancer Registry via the central population register. The study covered all eligible mobile phone users in Denmark from 1982-1995.

"All in all, 3,391 cancers were observed in the sample whichis remarkably close to those expected on the basis of incidence rates in the general population," Johansen said. Concern about mobile phones stems from the fact that when used, they emit low levels of radio frequency (RF) energy or radiation, scientists say.

Although the Danish study said radiation at sufficientlyhigh levels could cause heating of parts of the body, a typical mobile phone operates at a low power output level with an associated ‘very low rise in brain temperature’.

"If it is assumed that tumour promotion occurs close to thesite of exposure, this finding provides additional evidence against a link between cellphone use and brain cancer," Johansen said.

Johansen, who expects the study to play a key role inpossible U.S. Lawsuits from brain tumour victims against mobile phone companies, said the fact that all data were gathered before the link between cellphones and cancer became a public issue gave the study greater credibility.

"These cancer patients were unbiased as to what caused thetumour," he said.