(Some common flaws in these studies: The summaries of the evidence weren’t comprehensive, the researchers often didn’t look at the quality of the studies they found, and they failed to do other simple things that would limit bias from creeping in. They also relied on case-control studies, a poor method to determine causality — more on that soon.) So we didn’t include these eight reviews in our analysis.
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.
The World Health Organization (WHO) says the intensity of radio frequency (RF) radiation from cell phones decreases exponentially the further the device is held away from the body. Therefore your safest bet it keep your cell phone as far away from your ear and body as possible at all times. Don’t carry it in your pocket, tucked into a bra strap, and definitely don’t sleep with it next to your head.
A carrier wave oscillates at 1900 megahertz (MHz) in most phones, which is mostly invisible to our biological tissue and doesn’t do damage. The information-carrying secondary wave necessary to interpret voice or data is the problem, says Dr. Carlo. That wave cycles in a hertz (Hz) range familiar to the body. Your heart, for example, beats at two cycles per second, or two Hz. Our bodies recognize the information-carrying wave as an “invader,” setting in place protective biochemical reactions that alter physiology and cause biological problems that include intracellular free-radical buildup, leakage in the blood-brain barrier, genetic damage, disruption of intercellular communication, and an increase in the risk of tumors. The health dangers of recognizing the signal, therefore, aren’t from direct damage, but rather are due to the biochemical responses in the cell.
Radiofrequency radiation is a form of electromagnetic radiation. Electromagnetic radiation can be categorized into two types: ionizing (e.g., x-rays, radon, and cosmic rays) and non-ionizing (e.g., radiofrequency and extremely low frequency, or power frequency). Electromagnetic radiation is defined according to its wavelength and frequency, which is the number of cycles of a wave that pass a reference point per second. Electromagnetic frequencies are described in units called hertz (Hz).