The use of mobile phones does not put subscribers at the risk of contracting brain tumors, according to a new study published online, in the Oct. 20 issue of the British Medical Journal.

The study, led by Danish researchers from the Institute of Cancer Epidemiology in Copenhagen, debunks earlier claims that mobile phones increased cancer risk among users. The researchers compared and followed-up on 358,403 mobile phone users in Denmark, between 1990 and 2007. As many as 10,729 cases of tumors of the central nervous system were found, the report stated.

The results, however, suggested that there were no increased risks of tumors of the central nervous system, providing little evidence for a causal association with use of mobile phones.

There was no indication of dose-response relation either by years since first subscription for a mobile phone or by anatomical location of the tumor-that is, in regions of the brain closest to where the handset is usually held to the head, wrote the authors of the study.

The research also presents sex-specific incidence rate ratios of tumors and indicates that the risk of tumors was close to unity for both men and women. However, it differed slightly when restricted to individuals with the longest mobile phone use.

With an average 13 years of subscription, the incidence rate ratio was 1.03 in men and 0.91 in women; among those with subscriptions of 10 years, brain tumor ratio was 1.04 in men and women each, while ratio of tumor of central nervous system was 0.90 in men and 0.93 in women.

Though recognized as the largest ever nationwide cohort study of mobile phone use, the study has drawn widespread criticism too.

According to Philippe Charlier, of the Forensic Department in Garches, the daily duration of use was not considered in the study.

It is the intensive use of a cell phone that could cause an increased risk of central nervous system tumour. Further studies with more precise data are necessary before excluding any sanitary risk of mobile phones, said Charlier.