Researchers from the National Toxicology Program (NTP) in the USA published a preliminary report about their findings on the association between radio frequency exposure through cell phone use and cancer in a rodent study. A higher incidence of brain and heart cancer was observed in male rats.
Use of cell phones is so deeply associated with our lifestyle that we often forget that these devices were almost nonexistent a decade ago. Therefore, we don’t have much feedback on their potentially harmful effects on health. Cell phones emit radio frequency radiation in very close proximity with our heads and it is still not clear if that radiation may present health issues. A parallel could be made with Pierre and Marie Curie, who dedicated their lives to the study of radioactive material without any doubts on the danger of the radiation emitted by those substances (they ultimately died of exposure to radiation). Well, in contrast with x-ray or γ-ray, cell phone radiations are non-ionizing and health consequences are definitely not on the same level of magnitude. However, the ubiquitous usage of cell phones nowadays, particularly with the kids, necessitates addressing this question.
Researchers from the National Toxicology Program (NTP) were asked by the US government to investigate this question. They published a preliminary report on their findings on the association between radio frequency exposure through cell phone use and cancer.
They exposed groups of 90 rats, separated by gender, to 3 different doses of radio frequency radiations (1.5, 3 and 6 W/Kg) for 9 hours per day, for 2 years. The control groups were composed of 90 male and 90 female rats. After sacrifice of the animals, they searched for signs of tumors in every organ.
They found a higher incidence of brain (glioblastoma) and heart (Schwannoma) tumours in male rodents exposed to the radiation. While none of the control group animals developed these types of tumours, the incidence of brain tumours varied from 0 to 3 cases in each of the exposed groups. In total, 11 out of the 540 male (2.0 %) and 3 out of 540 female (0.6 %) rats developed brain tumours. However, the incidence was not higher for the highest dose of radiation. For heart tumors, 1 to 6 cases per group for male and 0 to 2 for female rats were observed, for a total of 19 out of 540 male (3.5 %) and 6 out of 540 female (1.1 %) rats.
These results are highly interesting and also disturbing. They tend to echo some epidemiologic study on humans however, they also raise many questions. First, why was the increase only significant in male rats? Second, why was the rate of brain tumour development in the control group lower than what was found in a previous study to be 2.0%? Finally, the control group was small in comparison to the test group, and curiously, why was the longevity of these animals shorter than the groups that received radiation?
It will definitely be long and challenging to clearly assess if the normal use of cell phones presents a significantly increased risk of brain tumour.
Written By: Jean-Michel Bourget, PhD