A massive long-term study designed to answer the question of whether cellphones cause brain tumours has offered some reassuring answers.
The study, which tracked the rate of brain tumors among Scandinavian people between 1974 and 2003, found no evidence that the increased use of cell phones during that time led to higher brain tumour rates.
"We did not observe an effect of mobile phones on the incidence of brain tumours," Prof. Isabelle Deltour told 麻豆影视.
Deltour, of the Institute of Cancer Epidemiology at the Danish Cancer Society in Copenhagen, led a study that tracked 16 million people in Finland, Denmark, Norway, and Sweden.
The team observed what happened to rates of glioma and meningioma brain tumours over 30 years, just as cell phones were introduced and their use exploded.
Just 60,000 people developed brain tumours, a rate that is not considered out of the ordinary, the authors report in the prestigious Journal of the National Cancer Institute.
"If there was a connection we would have expected a sudden marked increase in the rates, especially among younger males, which were the first to start using mobile phones. And we don't see that," Deltour said.
The authors say their finding may be due to one of several reasons:
- the period needed for cell phones to cause brain tumours was longer than the period studied
- the increased risk in this population is too small to be observed
- the increased risk is restricted to just certain cell phone users
- or there is no increased risk at all
Those who speak for the cell phone industry say they will continue to monitor other cell phone and cancer studies underway.
"We consider our products to be safe, we use them ourselves and our families do too and we want to continue to make sure they are safe," says Bernard Lord of the Canadian Wireless Telecommunications Association.
Even the scientists who conducted this study say longer-term studies are still needed and they will continue to monitor brain cancer rates, to see if it perhaps takes longer to detect changes in tumour rates.
Other scientists are waiting for a huge international study coming out next year that they say will be the definitive word on whether cell phones are linked to brain cancer.
"The story is not concluded," says Prof. Daniel Krewski of the McLaughlin Centre for Population Health Risk Assessment at the University of Ottawa.
Krewski added that the scientific community is eagerly awaiting the results of a World Health Organization study, which is expected in the coming months.
Still, for now, it is a bit of reassuring news, about a piece of technology that has become a fixture of modern living.
