A few comments (looooong rant):
Gliomas, the tumors mentioned in the report, account for around 50% of all primary tumors in the central nervous system (CNS). Primary tumors are tumors arising in the CNS. (Secondary tumors are metastases from tumors outside CNS, they constitue 30% of all CNS tumors, but are of no interest here). These tumors develop from the supporting cells in the CNS, few tumors arise from the nerve cells which have lost their ability to divide completely. There are several subtypes of gliomas, all of them are malignant, but the degree of malignancy and therefore prognosis varies. However, in the CNS the separation between malignant and benign tumors is not as important as elsewhere, because a benign tumor may easily kill you if you can't remove it - which is often the case inside the brain. I addition, event highly malignant tumors rarely give rise to metastases outside the brain.
In 2008 882 primary CNS tumors were reported to the Norwegian Cancer Registry. To compare the spread of disease between population or over time we are more interested in the incidence rate, the number of new cases related to the size of the population, usually given as the number of cases per 100 000 people per year. The registry publishes average incidence rates over 5 year periods since 1953. Thse numbers include all CNS tumors, I couldn't find any statistics only for gliomas.
The numbers:
1989-93: 9.8/100000
1994-98: 11.1/100000
1998-03: 14.0/100000
2004-08: 15.3/100000
GSM phones were according to Wikipedia introduced in 1992. It takes several years for these tumors to develop, therefore the incidence for the 1989-93 period can hardly be affected by cell phones or wifi networks and can be used as a baseline. There is a 55% increase in incidence between 89-93 and 2004-08. However, the reported incidence of CNS tumors have increased steadily since 1953. Between 69/73 and 84/88 the incidence increased by 49%, on the average we see a 30% increase for every 15-yeear interval.
Several known factors contribute to these numbers.
1. Better diagnostics and better reporting routines.
2. We get older. Gliomas peak at 65-70 years of age, so when the number of >65 year olds increase, so does the incidence.
3. Exposure to ionizing radiation to the head. That is particle- and gamma-rays from radioactive nuclei and most important: x-rays (high-frequency UV rays are also ionizing, but they don't penetrate into the body). The number of x-ray examinations have increased tremendously during this period. Of special importance are high-dosage examinations like CT scans, cerebral angiography (examination of blood vessels in the brain) and intervention procedures (x-ray guided intravascular treatment of bleeding and obstructions to blood flow). Most simple x-ray exams are low dosage exposures. Ultrasound and MRI don't involve ionizing radiation.
BTW, radio frequency radiation is not ionizing, there's not enough energy. However it does generate heat, which has been the main cause for concern regarding cell phones.
We know that these 3 factors are important. While there are some indications that cell phones/wi-fis is too, we still can't say for sure. OTOH, we can't say that it's risk free either. The numbers and the (admittedly, but hopefully not too amateurish) analysis I've provided here, don't bring us any closer to the truth, I don't pretend or attempt to prove anything.
But it seems to me that if there is any cancer risk, it can only be modest. The number of cell phones in use in Norway exploded during the nineties. In 2000 80% of all norwegians had a and presumably used cell phone (I was not one of those!!!). If the use of cell phones were a major cause, I would have expected significantly higher incidence rates after 2005 than what we see. BTW, cell phone penetration is closer to 98%% now (I'm one of those).
So, most likely the cancer risk of cell phones pales when compared to other (not cell phone related) health risk factors, such as the amount of saturated fat and sugar we eat, lack of exercise and smoking (the latter increase the risk of lung cancer by a factor of 5-10). All in all, I'm not particularly worried.
Some final comments:
1. I have not considered other possible health effects of cell phones.
2. Have you tested your house for Radon? Radon is a radioactive gas that can accumulate in people's homes, and is a known, important cause of lung cancer. I'm asking because recently a gallup in Norway indicated that while people in general were very concerned about radiation and still unproven health risks from cell phones and power lines, there were very little worry about well proven health risks from Radon. If you live in an (relatively) high Radon region, I recommend that you get your house tested.
3. Some studies indicate that people with type 1 allergies (hay fever and urticaria) have a reduced risk for CNS tumors. Nothing is sure, but I'M CONVINCED THIS IS TRUE. *grabs a tissue, sneezes*
4. I'll check the post for typ0 ed tomorrow.
