Sunday, December 6, 2009

Extensive 30-year study shows no link between mobile phones and brain tumors

A large, 30-year study, covering virtually everyone in Scandinavia, shows no link between mobile phone use and brain tumours, according to a Reuters report.

Even though mobile telephone use soared from the 1990s , brain tumours did not become any more common, the researchers reported in the Journal of the National Cancer Institute.

Over the years, various activist groups and researchers have raised concerns about a link between mobile phones and several kinds of cancer, including brain tumours, although years of research have failed to establish a conclusive connection, the Reuters report claims.

"We did not detect any clear change in the long-term time trends in the incidence of brain tumours from 1998 to 2003 in any subgroup," Isabelle Deltour of the Danish Cancer Society wrote.

Deltour's team analyzed annual incidence rates of two types of brain tumour – glioma and meningioma – among adults aged 20 to 79, from Denmark, Finland, Norway, and Sweden, from 1974 to 2003. This represented virtually the entire adult population of 16 million people, the researchers said. The Scandinavian countries all have comprehensive cancer registries that record details of known cancer cases.

"In Denmark, Finland, Norway, and Sweden, the use of mobile phones increased sharply in the mid-1990s; thus, time trends in brain tumour incidence after 1998 may provide information about possible tumour risks associated with mobile phone use," the researchers wrote.

Over the 30 years, nearly 60,000 patients were diagnosed with brain tumours. While the team did see a small, steady increase in brain tumours, this started in 1974, long before mobile phones arrived.

"No change in incidence trends were observed from 1998 to 2003," the researchers noted. This would have been when tumours would start showing up, assuming it took five to 10 years for one to develop, they said.

Most scientific studies show no association between mobile phone use and brain tumours, and researchers trying to find a connection have failed to find any biological explanation for how a mobile phone might cause cancer, according to the Reuters report.

"Because of the high prevalence of mobile phone exposure in this population and worldwide, longer follow-up of time trends in brain tumour incidence rates are warranted," the research team cautioned.


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