Cell Phone Exposure Shown to Increase Brain Glucose Metabolism

Reference

Volkow N, Tomasi D, Wang G-J, et al. Effect of cell phone radiofrequency signal exposure on brain glucose metabolism. JAMA. 2011;305(8):808-813.

Design

Randomized crossover study

Setting

Study conducted between January 1 and December 31, 2009, at a single US laboratory.

Participants

47 healthy participants recruited from the community

Study Method

Cell phones were placed on the left and right ears, and positron emission tomography was used to measure brain glucose metabolism, comparing exposure to both an activated cell phone and a deactivated cell phone for 50 minutes.

Outcome Measure

Brain glucose metabolism computed as absolute metabolism (μmol/100 g per minute) and as normalized metabolism (region/whole brain)

Key Findings

In healthy participants, 50 minutes of cell phone exposure was associated with increased brain glucose metabolism in the region closest to the antenna compared with no exposure.

Practice Implications

For years, medical experts and scientists have voiced concerns regarding the questionable safety of cell phone use, but even with the evidence mounting, this alluring technology is hard to resist. Humankind's increasing use of cell phones, 5 billion users worldwide, necessitates a thorough, unbiased look at the risks.

The study refutes the longstanding claim by both the Federal Communications Commission and the cell phone industry that there are no biological effects from non-thermal levels of cell phone radiation.

The JAMA study documents that cell phone exposure affects the brain by increasing brain glucose, a known measure of increased brain activity. Though the study does not offer an explanation of the underlying mechanism, we do know that in other biological systems of the body, chronic increase in glucose can have a significant effect on the local tissues, altering cell and gene function. Notably, the study refutes the longstanding claim by both the Federal Communications Commission and the cell phone industry that there are no biological effects from non-thermal levels of cell phone radiation.

The studies published on cell phone use and the possible health risks (including tumors of the brain,¹ as well as male infertility²) are numerous, and many repudiate any risks. Among the catalogue of studies, often funded in part by the cell phone industry, a meta-analysis published in the Journal of Clinical Oncology in 2006, involving 23 case-controlled studies and almost 38,000 participants, concluded there are increased health risks.³ Recently a branch of the World Health Organization called The International Agency for Research on Cancer (IARC) convened 31 scientists from 14 countries, including the United States, and evaluated peer-reviewed studies regarding the safety of cell phones and issued a statement that puts exposure to radiofrequency electromagnetic fields from cell phone use in the same category as lead and car exhaust: possibly carcinogenic.⁴

At what point do we acknowledge that precautions need to be taken? Our current safety standards regarding cell phones are based on obsolete research. They certainly don't take into account the dramatic increase in number of users, the increase in amount of time spent in use, and the rise of cell phone use by young people. There not only needs to be continued investigation into the effects on brain tissues, but also the consequences of both heavy use and long-term exposure—parameters not yet studied.

The concept of the precautionary principle encourages policy makers to make decisions that protect the public from a policy or action that may be harmful, in the absence of definitive data. In looking at the health impacts of electromagnetic radiofrequencies from cell phones, the public needs to be protected from the harm that may be caused by their use. It calls to mind our history regarding tobacco, when medical professionals awaited definitive trial data for decades, while millions of individuals suffered predictable health consequences. By refusing to acknowledge the possible health risks of cell phone use now, we may be harming generations to come.

While we continue to gather information, we can counsel our patients on the many ways to reduce overall electromagnetic radiation exposure:

• Turn cell phones off when not in use. Cell phone emissions are occurring whenever the phone is on, whether it is being used or not.
• Avoid cell phone use when the signal is weak. Emissions increase while the phone is searching for a tower.
• Store cell phones away from the body in a purse, backpack, or briefcase.
• Use a protective headset that puts distance between the phone and the brain, with corded earphones if possible.
• Engage in texting in lieu of phone calls.

We can assume there will be continued development of the technology, including safer phones and safer designs for towers. Ultimately, curbing cell phone use—using our cell phones for truly important communications and turning them off when they are not needed—may be the key to reducing risk.