Is there a correlation?
Most people nowadays have a cellphone and use it almost constantly. There have been some concerns that due to the electromagnetic fields that phones create, you might have a higher risk of developing cancer. How likely is this true? If it is true, is there anything that you can do to reduce your risk level?
For in the United States in 2019, the estimated number of new people who will be diagnosed with brain or other central nervous system cancers is almost 24,000 and the number of deaths is expected to be almost 18,000. While the number of people diagnosed has declined slightly in recent years, the number of deaths has increased slightly. In any case, when faced with a cancer diagnosis many people want answers as to what caused it. Given the popularity of cellphones, they’ve become a point of focus. Cellphones first became widely available in the United States in the 1990s and by the end of 2017, there were over 400 million cellphone subscribers in the US, according to the Cellular Telecommunications and Internet Association. If you scale that number globally, it means that there are more than 5 billion cellphone users. From the time that they were first introduced until now, their use has increased significantly in regards to volume of calls per day and the length of each call.
What is it about cellphones that could be so bad? They work by sending and receiving signals from nearby cell towers using radiofrequency (RF) waves, which is a form of electromagnetic radiation. Electromagnetic radiation is defined by its wavelength and frequency, which is the number of cycles of a wave that pass a reference point per second. This is measured in units called hertz (Hz). The energy of electromagnetic radiation is classified by its frequency into ionizing and non-ionizing. Ionizing radiation is high frequency, so high energy; whereas non-ionizing radiation is low frequency, so low energy. Exposure to ionizing radiation is known to increase an individual’s risk of cancer. An example of ionizing radiation is an X-ray or ultraviolet (UV) light. Non-ionizing radiation isn’t shown to have that same risk. An example of non-ionizing radiation is a microwave or FM radio waves. Radiofrequency waves fall somewhere between these last two. Since the human body absorbs energy from devices that emit radiofrequency waves, the concern with cellphones is that the antenna inside the phone is emitting these RF waves and your brain is absorbing them since you hold the phone close to your head to talk on it. The amount of energy that is absorbed is estimated using a measure called the specific absorption rate (SAR), which is conveyed in watts per kilogram of body weight (W/kg). There isn’t a standard SAR rate of cellphone, which means each one has its own SAR level. In order to keep track of this, cellphone makers must report the maximum SAR level of their products to the US Federal Communications Commission (FCC), which is one of the regulatory bodies who oversee them. The upper limit that is allowed is 1.6 W/kg. If you want to find out the SAR level for your phone, you can find this on the manufacturer’s website, in the user manual for the phone or on the FCC’s website using the phone’s FCC ID number (usually located on the case of the phone). It’s important to keep in mind that the listed SAR value is based only on the phone operating at its highest power, not what you would typically be exposed to with normal phone use.
Despite the fact that cellphones emit RF waves, the possible connection between them and cancer isn’t clear. There have been several epidemiologic studies done to investigate this possible relationship. One type of study is a case–control study, which means cellphone use was compared between people with brain tumors and people without them. Another type of study is a cohort study and was when a large group of people who do not have cancer at the beginning of the study are followed over time to see the rate of brain tumor development in people who did and didn’t use cellphones. The largest health-related case–control study of cellphone usage and risk of brain tumors was called the Interphone study. It was done by researchers from 13 countries and looked at the cellphone usage of more than 5,000 people who developed brain tumors and another 5,000 people who did not have brain tumors. In order to gather the data, study participants filled out questionnaires. The results showed that there were no statistically significant increases in brain tumors related to higher amounts of cellphone use. A cohort study done in Denmark, thus called the Danish study, looked at the billing information from almost 360,000 cellphone subscribers and paired it with data from the Danish Cancer Registry on people who had brain tumors. The results indicated that there is no association between cellphone use and the incidence of brain tumors. A different cohort study from the United Kingdom called the Million Women study, used questionnaires to obtain data from almost 800,000 women who self-report their cellphone use habits. This study didn’t find any links between cellphone use and brain tumors overall, but it did find a possible connection between long-term cellphone use and acoustic neuromas (a noncancerous tumor on the main nerve leading from the inner ear to the brain).
There have been other, smaller epidemiologic studies done to look for associations between cellphone use and cancer. Two case–control studies were sponsored by the National Cancer Institute (NCI) with each conducted in multiple US academic medical centers between 1994 -1998. They used data from questionnaires or computer-assisted personal interviews and neither found any connection between cellphone use and the risk of developing a brain tumor. The NCI also had the Surveillance, Epidemiology, and End Results (SEER) Program, which evaluated trends in cancer in the US. For the period of 1992 – 2006, the data didn’t find an increase in the number brain tumors, despite the dramatic increase in cellphone use during this time. A different case–control study done in several areas across France from 2004 – 2006, called the CERENAT study, collected data in face-to-face interviews using a standardized questionnaire. It also didn’t find any association for brain tumor development when comparing regular cellphone users with non-users. An analysis of data from Denmark, Finland, Norway and Sweden for the period 1974 – 2008 demonstrated no increase in age-adjusted incidence of brain tumors. However, in a pooled analysis of two other case–control studies from Sweden found statistically significant amount of increasing brain cancer risk for the total amount of cell phone use and the years of use among people who began using cell phones before age 20. Yet, the CEFALO study, which was an international case–control study of children diagnosed with brain cancer between ages 7 and 19. It was conducted in Denmark, Sweden, Norway and Switzerland between 2004 and 2008. The study didn’t find any association between cellphone use and brain tumor risk either by time since initiation of use, amount of use or by the location of the tumor.
Globally, there are several organizations that help to identify and classify anything that could be carcinogenic to humans. In the US, the main agencies do this are the Environmental Protection Agency (EPA) and the National Toxicology Program (NTP). In 1999, NTP studied radiofrequency radiation using 2G and 3G frequencies in rats and mice. It was a large project that was conducted in highly specialized labs with the ability to specify and control sources of radiation in order to measure the effects. During the study, the rodents received whole-body exposures of 3, 6 or 9 W/kg for 5 or 7 days a week for 18 hours a day in cycles of 10 minutes on, 10 minutes off. The main outcome was a small number of cancers in the heart for male rats, but not female rats or mice of either gender. In 2018, the NTP reported this link between cellphone radiation and brain tumors in male rats. The first problem with this study is that the exposure level, duration and exposed area (the entire body) for the rodents far exceeds that of human cellphone use. The second problem is that it can take a while to measure the health effects of something and, in this case, the advances and use of cellphone technology have far outpaced understanding of the potential health consequences. The technology had significantly changed since the beginning of the NTP study. In 2018, the American Cancer Society (ACS) issued a statement on the NTP reports noting that the findings are inconclusive, and that, thus far, a higher cancer risk in people has not been seen.
The Food and Drug Administration (FDA), the other regulatory body in the US who oversees cellphones, originally nominated cellphone to be reviewed by the NTP to determine exposure levels. In response to the NTP reports, they issues a statement saying that based on the current information, the current safety limits for cellphones are acceptable for protecting the public health. The FCC also concludes that there’s currently no scientific evidence to establish a definite link between cellphone use and cancer or other illnesses, including headaches, dizziness or memory loss. Several other health agencies across the US have also commented on the NTP report. According to the Center for Disease Control (CDC), there isn’t sufficient evidence to link health problems to cellphone use. The National Cancer Institute (NCI) said studies done thus far have not shown a consistent link between cellphone use and cancers of the brain, nerves or other tissues of the head or neck. The National Institute of Environmental Health Sciences (NIEHS), which is currently conducting studies of the possible health effects of cellphones, responded to the NTP reports that the current scientific evidence doesn’t conclusively link cellphone use with any adverse health problems, but further research is needed. Due to changes in technology, organizations in the US and across the globe are sponsoring research and investigating claims of possible health effects related to the use of cellphones.
The International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO), is responsible on a global scale for identifying causes of cancer. In 2011, they formed a Working Group to review all available evidence on cellphone use. Based on limited evidence from human studies and limited evidence from studies of radiofrequency radiation and cancer in rodents, they found that cellphones could possibly be carcinogenic to humans, but the evidence is very limited. Due to the possibility, they classified radiofrequency electromagnetic fields as possibly carcinogenic to people. Shortly after this announcement, the ACS stated that the IARC classification indicates that there could be some cancer risk associated with radiofrequency radiation, but the lack of evidence means that it needs to be investigated further.
It can take years between the use of a new product and observing an increase in cancer rates from it. In the case of cellphones, direct measurements are not yet possible outside of a laboratory setting. This means that the majority of the information is self-report and must take into consideration several things. How old were they when they first started using a cellphone? How many years have they used a cellphone? What is the average number of cellphone calls per day, week, or month do they have? How long are the calls? All of this data helps to calculate the total hours of lifetime use. Despite having all this information, all studies done so far have been limited for several reasons. The first problem is that the studies rely on people’s memories about their past cellphone use. This can cause issues with recall bias. This can happen when data about prior habits and exposures are collected from individuals after they’ve been diagnosed with a disease, so they’re trying to find a cause for their illness, which might cause them to overreport their actual usage. Also, participation bias is common because when people are diagnosed with cancer, they’re more likely than healthy people to enroll in a research study. Another issue is inaccurate reporting from people not remembering exactly how much they used their cellphone during a specific time period. Unfortunately, the morbidity and mortality among those who have cancer, particularly gliomas (an aggressive form of brain cancer), is high and the patients who survive are often impaired, which can impact their responses to questions. Another factor is how cellphones are designed is constantly changing. Older studies looked at radiofrequency radiation exposure from analog cellphones, but new cellphones use digital technology, which operates at a different frequency and a lower power level. Also, while people may be using their cellphones more now than they were ever before, the phones, themselves, are very different from what was used in the past thanks to the advances in technology, including texting, other applications and hands-free technology becoming more popular. Since these don’t require bringing the phone close to your head, the concern of radiation is less of an issue. These changes make it hard to know if the results of studies looking at older cellphones would still apply today. An additional consideration is that most of the studies published have focused on adults, rather than children. There are several concerns when it comes to children because it’s possible that if there are health effects from cellphone usage, they might be more noticeable in children because their bodies might be more sensitive to RF energy since they’re still growing. Since their nervous systems are still developing, they could be more vulnerable to factors that may cause cancer. Also, their heads are smaller, which means they have a greater proportional exposure to the RF radiation that is emitted by cellphones. A further consideration is the fact that their lifetime exposure will be far greater than adults since they started using cellphones at a younger age.
In order to gain a better understanding of whether or not there is a correlation between cellphones and cancer, there are several studies ongoing across the globe. One is a large prospective cohort study of cellphone use and its possible long-term health effects was launched in Europe in March 2010. It’s called COSMOS and has enrolled approximately 290,000 cellphone users 18 years old or older with the intent to follow them for 20 to 30 years. In order to get a comprehensive data set, participants completed a questionnaire about their health, lifestyle and cellphone use currently and in the past. In addition to the questionnaire, the study is examining information from participants’ health and cellphone records. The goal of this study is to follow the participants for a range of health effects over many decades.
Until more information is available about long-term cellphone use and the risk of cancer, there are several things you can do to limit your exposure to RF radiation. The big one is to use the speaker mode on the phone or a hands-free device. Most earpieces have an SAR value of around 0.001 watts/kg. Another option is to text instead of talk on the phone (just make sue it’s safe to do so—not while driving). Limit the time you and your children spend on cellphones. Also, don’t carry your cellphone against one area of their body. Be sure to not sleep with your cellphone under your pillow. It’s important to avoid using your cellphone when you have a weak signal because the phone increases its RF radiation trying to connect. Same thing happens when you use your cellphone to download large files or stream videos. Be careful of products like RF radiation shields or other devices that claim to reduce your exposure because many may actually increase the amount of radiation. Also, we should be pushing for clearer labeling and information about RF radiation exposure on products.
Cellphones have definitely improved many aspects of our lives. Thankfully, the studies we have so far don’t show any signs of them increasing your risk of cancer. However, until more studies are done over longer periods of time, we can’t know for sure. So, in the meantime, it’s a good idea to take the steps necessary to protect yourself from radiofrequency radiation exposure.