Cell phones increase the rate of two types of brain tumor, according to a study. Using mobile phones for more than 10 years gives a consistent pattern of increased risk for at least two different types of brain tumors. This was the conclusion of a summary that reviewed sixteen other research studies from seven countries – USA, Finland, Sweden, Denmark, United Kingdom, Germany, and Japan.(1)
Cell Phones Are Like Radios
Cell phones are more like radios than traditional telephones in your home. They emit low levels of radiofrequency energy (RF) in the microwave range while being used. They also emit very low levels of RF when in the stand-by mode. Using a cell phone can place the radiation antenna close to the user’s brain and this can lead to the absorption of comparatively large amounts of electromagnetic energy.
There has been an on-going debate about the safety of cell phones for many years. While, not surprisingly, the cell phone industry and various health authorities have assured users that the technology is safe, recent research has suggested otherwise.
Researchers at the Department of Oncology, University Hospital in Sweden reviewed sixteen published studies that looked at cell phone use and the rate of brain cancers. They concluded that:
“For both acoustic neuroma and glioma (two types of brain cancer), overall risk was increased in the whole group, but significantly increased for ipsilateral exposure (tumor on the same side of the brain as cell phone exposure)…These results are certainly of biological relevance, as the highest risk was found for tumors in the most exposed area of the brain, using a latency period that is relevant in carcinogenesis.”
Increased Risk of Acoustic Neuromas
Acoustic neuromas, also called schwannomas, are a non-cancerous tumor that develops on the nerve that connects the ear to the brain. The tumor usually grows slowly. As it grows, it presses against the nerves responsible for hearing and balance. Radiosurgery is usually the standard treatment.
Signs and symptoms of acoustic neuromas may include hearing loss, usually gradual – although in some cases sudden – and occurring on only one side or more pronounced on one side, ringing (tinnitus) in the affected ear, dizziness (vertigo), loss of balance, facial numbness and tingling. The tumor also may press on the brainstem and in rare cases, it may grow large enough to compress the brainstem and be life-threatening.
After reviewing the previous studies that looked at cell phone usage and neuromas, the authors found “an association with acoustic neuroma…in four studies in the group with at least 10 years use of a mobile phone.”
Their discussion of this issue included the following observations:
· Acoustic neuroma might be a “signal” tumor type for increased brain tumor risk from microwave exposure, as it is located in an anatomical area that receives high exposure during calls with cellular or cordless phones.
· Three studies did not have follow-up of at least 10 years, but two of them showed a somewhat increased risk for shorter latency periods.
· Three of the four studies with data on over ten years use showed a statistically significantly increased risk overall or for ipsilateral exposure to microwaves. (In this context, ipsilateral exposure means the tumor is on the same side of the brain as cell phone exposure).
· In one study, no association was found but the result was based on only two cases.
· The tumors were significantly larger among mobile phone users.
Increased Risk of Gliomas
The researchers also found that the risk of glioma increased significantly per year of use.
A glioma is a type of primary central nervous system (CNS) tumor that arises from glial cells. The most common site of involvement is the brain, but they can also affect the spinal cord or any other part of the CNS, such as the optic nerves. Gliomas can be either benign (slow growing) or malignant (fast growing). Types of gliomas include:
· astrocytomas · ependymomas · oligodendrogliomas · mixed gliomas
Treatment for a glioma — and survival odds — depends on tumor type, size and location, and the patient’s age and overall health. Often, treatment is a combined approach, using surgery, radiation therapy, and chemotherapy. High grade gliomas like anaplastic astrocytomas and glioblastoma multiforme can be particularly difficult to treat.
Symptoms of gliomas depend on which part of the central nervous system is affected. A brain glioma can cause headaches, nausea and vomiting, seizures, and cranial nerve disorders as a result of increased intracranial pressure. A glioma of the optic nerve can cause visual loss. Spinal cord gliomas can cause pain, weakness or numbness in the extremities.
In respect to gliomas and cell phones, the researchers concluded “that using a ten year or more latency period gives a consistent pattern of association between use of mobile phones and malignant brain tumors, especially high-grade glioma.” The researchers also found an increased overall risk more pronounced for ipsilateral use of the cell phone (tumor on the same side of the brain as cell phone exposure).
What to Do?
This study did not say that cell phone use leads to brain tumors, only that long-term use may increase one’s statistical risk of certain brain tumors. In addition, it should be noted, that other studies have concluded that there is no connection between cell phones and increased risk of cancer. This issue is far from resolved. But for those heavy cell-phone users who want to err on the side of caution, it may be wise to use one of the various non-RF devices (such as headphones) that can place some distance between a cell phone and the user’s brain.
(1) Hardell L, et al., Long-term use of cellular phones and brain tumours: increased risk associated with use for > or =10 years. Occup Environ Med. 2007 Sep;64(9):626-32.