New Delhi: The question of whether or not cell phones cause cancer has been under scrutiny for years now. A major study released by the US National Toxicology Program has now revealed that exposure to radiofrequency radiation emitted by cell phones resulted in higher incidences of two types of cancer in mice. The new study is likely to revive the debate in the scientific community about cell phone radiation being carcinogenic.

The two-year study was conducted using more than 2,000 rats which were exposed to radiofrequency radiation at frequencies and modulations used in the US telecom industry. The partial findings from these studies were released late Thursday.

“Given the widespread global usage of mobile communications among users of all ages, even a very small increase in the incidence of disease resulting from exposure to radiofrequency radiation could have broad implications for public health," the report said.

The study revealed that exposure to radiation in male rats resulted in a statistically significant and positive trend in the incidence of schwannomas which are a kind of tumour, in the heart. The increase in the incidence of schwannomas in the heart of male rats in this study is likely shown to be the result of whole-body exposures to radiofrequency radiation. In the brain also, there was a significant, positive trend in the incidences of malignant gliomas in males exposed to radiation, the study said.

The study concluded that under the conditions of these two-year studies, the tumours of the heart and brain observed in male rats are considered likely the result of exposures of the mice to radiation. The study highlighted that the tumours in the brain and heart observed at low incidence in male rats exposed to cell phone radiation in this study are of similar to the type of tumours observed in some epidemiology studies of cell phone use.

“These findings appear to support the International Agency for Research on Cancer (IARC) conclusions regarding the possible carcinogenic 5 potential of radiofrequency radiation," noted the study.

In 2013, IARC classified radiofrequency radiation as a possible human carcinogen based on “limited evidence" of an association between exposure to radiofrequency radiation from heavy wireless phone use and glioma and acoustic neuroma, which are types of tumours, in human epidemiology studies.

Carcinogens are increasingly present in people’s daily lives. From mobile phone radiation to atmospheric pollution and tobacco smoke, the World Health Organization’s IARC has currently listed at least 900 carcinogens on varying levels of surety about how carcinogenic they are.

But there is also increasing evidence to the contrary regarding mobile phone radiation’s link to cancer. In 2015, the European Commission Scientific Committee on Emerging and Newly Identified Health Risks concluded that, overall, the epidemiologic studies on cell phone radiofrequency electromagnetic radiation exposure do not show an increased risk of brain tumours or of other cancers of the head and neck region.

The report warned that the results reported are limited to select findings of concern in the brain and heart and do not represent a complete reporting of all findings from these studies of cell phone radiofrequency radiation.