A recent small study in people has shown that cell phones may also have some other effects on the brain, although it’s not clear if they’re harmful. The study found that when people had an active cell phone held up to their ear for 50 minutes, brain tissues on the same side of the head as the phone used more glucose than did tissues on the other side of the brain. Glucose is a sugar that normally serves as the brain’s fuel. Glucose use goes up in certain parts of the brain when it is in use, such as when we are thinking, speaking, or moving. The possible health effect, if any, from the increase in glucose use from cell phone energy is unknown.
Searching PubMed for studies published in the past 10 years, we found 102 studies that ultimately resulted in 12 relevant systematic reviews. To limit bias in our assessment of the literature, we used a validated critical appraisal tool called AMSTAR to determine the quality of each review. Eight of the reviews were critically low quality, two were low quality, and two were moderate quality.
Independently tested DefenderShield technology uses a patent-pending sophisticated layering of separate non-toxic, human safe materials processed for maximum radiation blocking efficiency. Each material has unique and targeted radiation shielding characteristics designed to work in unison to up to eliminate all radiation emissions from 0 to 10 GHz.
People can also reduce their exposure by limiting cell-phone use when the cellular signal is weak; when traveling in a high-speed car, bus or train; to stream audio or video; or to download or upload large files. All of these circumstances cause phones to put out higher-than-normal levels of RF energy. Phones also emit RF energy when connected to WiFi or Bluetooth devices, but at lower levels.
Finally, Brawley reminded me that cellphones kill humans in another way that we’re already certain about: because of inattention through distracted driving. In the US alone, there were 3,157 fatal crashes in 2016 that involved distracted driving, 14 percent of which included cellphone use, according to the latest data from the National Highway Traffic Safety Administration. That’s not the focus of this piece, but perhaps state and federal regulators could follow places like Washington state, California, New York, and Nevada and heavily crack down on distracted driving with bans or stricter laws.
Remember: The cancer incidence data in humans, at least to date, suggests no avalanche of head and neck tumors. Since so many people are exposed to cellphones, if there were a big risk, we’d probably see it turn up. “If cellphones caused brain tumors at the rate that cigarettes caused lung cancer,” said Otis Brawley of the American Cancer Society, “we would have figured it out by now.”
Exposure to ionizing radiation, such as from x-rays, is known to increase the risk of cancer. However, although many studies have examined the potential health effects of non-ionizing radiation from radar, microwave ovens, cell phones, and other sources, there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans (2).