The debate continues, as studies using rats are convincing but still inconclusive about human implications.
Mobile Phone use has changed the way we live
Mobile phones have brought a lot of convenience to our lives and, depending on the extent to which we use them, smart phones in particular have revolutionized the ways we communicate, travel and do business. In 2017, an impressive 92% of 18- to 29-year-olds said they owned a smart phone and 95% of all Americans own a mobile phone of some kind. So it’s not surprising that there is so much interest in establishing once and for all how safe they are.
Humans and animals are subject to different types of non-negotiable radiation exposure as part of daily life. When we travel in airplanes, use computers or live close to cell tower arrays or power lines, we can assume we are being exposed to radio frequency (RF) We are also surrounded by a certain amount of radiation from the electrical appliances we use in our homes and at work. Cell phones emit a type of RF that was classified as a Group 2B “possible” human carcinogen in 2011 by the International Agency on Cancer (IARC), an agency of the World Health Organization. Understandably, this classification rang a lot of alarm bells and there are entire websites devoted to advising consumers how to protect themselves from RF exposure. The U.S. Federal Communications Commission’s limit for public exposure to cell phones is 1.6 watts W/kg.
Even if we’re not actually using our cell phone, it is constantly communicating with cell towers etc., especially if the owner has installed navigation and calendar apps that are constantly trying to remain updated with the phone’s location when left open.
A Long History of Research
Because this is such a pressing issue, with widespread human health implications, there have been hundreds of studies over the years since cell phones and smart phones have been widely adopted for regular use. Recently published studies have added to decades of debate about the safety of cell phone use and whether or not there is a link to the observed incidence of brain tumors and other types of cancer in humans.
A few epidemiology studies have reported higher than average rates of tumors inside the skulls of people who use cell phones more than average amounts for ten years or more. Several research studies have been criticized for possible bias as they have often been funded by cell phone companies, who may have a vested interest in the outcome of the results. Seventy-two percent of industry-funded studies have failed to make a significant link to health risks from cell phone exposure, while sixty-seven percent of independent studies (not funded by the wireless communications industry) did find biological effects. Perhaps the first notable, independently funded study to examine long-term effects of using cell phones was conducted in the 1990s by Lennart Hardell, professor of oncology at Orebro University in Sweden. He found that cell phone users were 2.5 times more likely to have a temporal brain tumor on the side of the head where they held their phone. His study compared 1,617 patients diagnosed with brain tumors with the same number of healthy people. He found that the risk of auditory nerve tumors was increased by 3.7 times for mobile phone users in the study. Hardell’s most significant conclusion was that 10 years of heavy cell phone use would result in a 26% increased risk of brain cancer. Beyond 10 years of heavy use, he suggested that the risk could rise to 77%.
Cut to: the Latest Published Research
The most recent studies, however, are worth our attention because they are considerably larger than previous ones we had to go on. Results of both of the studies mentioned below were published in 2018, although the NTP study results were leaked in 2016.
A study conducted by scientists at the National Toxicology Program (NTP), a federal inter-agency group under the National Institutes of Health, cost $25 million and began over ten years ago. It used 3,000 male and female rats and mice for a period of two years. It monitored the rates of heart schwannomas (these occur in rats but rarely in humans) and lymphoma, as well as cancers affecting the skin, prostate, lung, liver and brain in the exposed animals. This study focused on ‘’near-field’’ exposures, similar to the way people are exposed to RF while using their cell phones. Cancer rates for the exposed subjects in all monitored categories increased but other factors that could have influenced the results could not be ruled out, rendering the results inconclusive. Somewhat unexpectedly, the RF-exposed rodent test subjects lived longer than their counterparts in the study that were not exposed to the RF.
The Ramazzini Institute (RI) in Italy also used rats as subjects, although their study differed in that they looked at ‘’far-field’’ exposure, which is basically the constant RF radiation that we are bathed in from our surroundings, including computer exposure and wireless frequencies. The Italian researchers used 2,500 rats and followed them throughout their entire lives, as they were exposed to far-field RF for 19 hours per day, from fetal development until death from natural causes.
The RI’s exposure measures were somewhat different from the absorbed doses calculated during the NTP study, but both studies yielded observable results that had some factors in common. Both noted higher incidence of heart shwannomas in the male rats that received the highest doses of RF exposure and some cancer of the glial cells in the brain linked to RF exposure in the females. This consistency is valuable because as Ronald Melnick, a retired NTP toxicologist who designed the NTP study says, “reproducibility in science increases our confidence in the observed results.” The rodents on the whole were exposed to higher levels of RF than is normal for humans, so “these findings should not be directly extrapolated to human cell phone usage,” said John Bucher, Ph.D., a senior scientist at the NTP. “We note, however, that the tumors we saw in these studies are similar to tumors previously reported in some studies of frequent cell phone users.”
So are we any the wiser?
So, even though there were factors identified in the above studies that suggested a link between RF exposure and certain types of cancer, the jury is still out on whether or not cell phones actually give us cancer, even with heavy usage. This is mostly because the scientists who conducted the studies did not regulate and monitor other variables such as diet, temperature and so on. So they did not establish an indisputable link between RF exposure from cell phones and cancer in humans. A panel of outside experts reviewed the results from both these studies during a three-day meeting that ended on March 28, 2018.
Their conclusion? That there was “clear evidence” linking RF radiation with heart schwannomas and “some evidence” linking it to gliomas of the brain. Now the NTP will either accept or reject the conclusions drawn by the independent experts. We should know their verdict in a few months.
Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, wrote in a statement on February 2nd that despite the NTP study’s results, the combined evidence on RF exposure and human cancer has “…given us confidence that the current safety limits for cell phone radiation remain acceptable for protecting the public health…We continue to agree with the FDA statement”.