Brain cancer has nothing to do with long-term use of mobile phones. Is this the final word?

Previous studies have shown that mobile phone radiation has a risk of causing cancer. The International Agency for Research on Cancer under the World Health Organization has even classified mobile phone radiation as a Class 2B carcinogen, which means it may cause cancer in humans. However, this has not stopped humans from becoming dependent on mobile phones. Carrying mobile phones with you all the time is almost a normal part of every modern person. Now, the most comprehensive review study to date has come out, concluding that there is no link between mobile phone radiation and brain cancer.

Written by | Mumu

With the popularity of smartphones in recent years, people's lifestyles have changed dramatically, and mobile phones have become an indispensable part of our daily lives. However, along with this convenience, many people have begun to worry about whether frequent use of mobile phones will have a negative impact on health, especially the debate about whether mobile phone radiation can cause cancer.

Recently, the results of the world's largest related study were officially released, which clearly pointed out for the first time that there is no significant correlation between mobile phone use and common brain cancer. This study not only provides important reference for public health policies, but also gives us a clearer understanding of the potential risks of mobile phone radiation.

To understand the relationship between mobile phone radiation and health, we need to first understand the different types of radiation. Radiation can be divided into two categories: ionizing radiation and non-ionizing radiation.

Ionizing radiation has enough energy to ionize atoms or molecules, knocking out electrons, which may cause DNA damage and induce cancer-causing gene mutations. Radioactive materials and X-rays are typical sources of ionizing radiation.

Non-ionizing radiation has lower energy and cannot ionize atoms or molecules. Cell phones, microwave ovens, wireless networks, and other modern electronic devices all produce radiation that is non-ionizing. The energy of this type of radiation (except ultraviolet light) is not enough to directly damage the DNA structure of organisms, so in theory, they are less likely to cause cancer.

However, as smartphones are used more and more frequently, people's concerns about the health risks of prolonged use of mobile phones are also increasing.

Image source: Pixabay

Therefore, the scientific community has also conducted a lot of research on the relationship between mobile phone radiation and cancer and various diseases. These studies are usually based on observational and experimental studies, and evaluate the potential impact of mobile phone use on human health through long-term tracking and experimental analysis. However, some research results are inconsistent.

Some studies in the past few years have reported that long-term and frequent use of mobile phones may increase the risk of brain cancer, especially certain types of brain cancer, such as glioma. However, these studies often have small sample sizes and certain limitations in research design, which makes the credibility of the results questionable.

On the other hand, many large-scale epidemiological studies have not found a significant association between mobile phone use and brain cancer incidence. Most of these studies are based on large amounts of data, analyzing health records of hundreds of thousands or even millions of people, and the results show that there is no direct relationship between exposure to mobile phone radiation and brain cancer risk.

Latest research: It’s not related

On August 30, 2024, a new study published online in Environment International magazine can be said to be the largest and most comprehensive study on the relationship between mobile phone radiation and brain cancer to date. The study was completed by scientists from multiple countries commissioned by the World Health Organization, collecting and analyzing data from more than one million people, covering the tracking records of 63 studies from 1994 to 2022.

The goal of this study was to assess the quality and strength of evidence from various human observational studies for a causal association between exposure to radiofrequency electromagnetic fields (RF-EMF) and the risk of the most common neoplastic diseases.

Image source: Environment International

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) led the study, which systematically reviewed more than 5,000 studies and selected the most scientific and rigorous studies. The screening criteria included cohort and case-control studies related to RF-EMF exposure, including near-field exposure, local head exposure (such as wireless phone use), far-field exposure, whole-body environmental exposure (such as fixed transmission station exposure) and near/far-field occupational exposure (such as handheld signal transceivers or RF transmitting equipment in the workplace); at the same time, it focused on the incidence of key central nervous system tumors (such as brain, meninges, pituitary gland, auditory nerve), salivary gland tumors and leukemia, and paid attention to the relationship between specific tumors and specific exposure sources.

The core conclusion of the study is that there is no significant association between mobile phone use and brain cancer.

Specifically, head near-field RF-EMF exposure from mobile phones (ever use, regular use, non-use, or infrequent use) was not associated with an increased risk of adult glioma, meningioma, acoustic neuroma, pituitary tumor, salivary gland tumor, or childhood brain tumor. Moreover, the incidence of the most common tumors (glioma, meningioma, and acoustic neuroma) did not increase significantly with increasing mobile phone use time, cumulative call time, or cumulative number of calls, and the incidence of brain cancer did not exceed the average even in the group with the highest frequency of mobile phone use.

In addition, whole-body far-field RF-EMF exposure from fixed transmitting stations (broadcasting antennas or base stations) is not associated with the risk of childhood leukemia or childhood brain tumors (there is a lack of relevant studies on fixed transmitting station RF-EMF exposure that meet screening criteria and common adult tumors); there is no significant increased risk of glioma after occupational RF exposure (there is a lack of relevant studies on occupational RF-EMF exposure that meet screening criteria and leukemia).

Image source: Pixabay

This means that no matter how often or how long a day a mobile phone is used, whether there are mobile communication base stations near home, or whether one deals with RF-EMF every day at work, there is no significant increase in the risk of common brain tumors.

"We concluded that the evidence does not show a link between mobile phones and brain cancer or other head and neck cancers," said Associate Professor Ken Karipidis, assistant director of health impact assessment at ARPANSA and corresponding author of the study. "I am quite confident in our conclusions. What makes us quite confident is that ... despite the surge in mobile phone use, brain tumour rates have remained stable."

"I think people should be reassured by this research," said Tim Driscoll, a professor at Sydney University and chair of the Australian Occupational and Environmental Cancer Council. "While these studies are not perfect, much of the evidence suggests that in terms of any concerns about increased cancer risk, mobile phones should be considered safe."

Therefore, this study is not only expected to dispel concerns that mobile phone use can cause cancer, indicating that the impact of non-ionizing radiation on human health may be much smaller than we previously thought, but the authoritative evidence provided by this result is also expected to provide strong support for public health policies worldwide.

A rational view of mobile phone radiation

Although scientific research has gradually revealed the truth, the public's concerns about mobile phone radiation still exist. This concern is mostly due to misunderstandings about radiation and distrust of modern technology. Many people generalize all types of radiation and believe that as long as it is "radiation", it is harmful. This concept has led to excessive panic about mobile phone radiation. However, as mentioned earlier, the physical properties of non-ionizing radiation are fundamentally different from those of ionizing radiation. It does not have the ability to directly damage DNA, so the possibility of causing cancer is extremely low.

In addition, social media and sloppy news reports often exaggerate the risks of mobile phone radiation and even spread "anti-radiation" products that have not been scientifically verified, further exacerbating public panic.

Karipidis, who is also vice-chair of the International Commission on Non-Ionizing Radiation Protection, said that mobile phones and any device that uses wireless technology, including laptops, radios and televisions, and mobile communication base stations, emit radio frequency electromagnetic radiation, but many people tend to think of it as similar to nuclear radiation when they hear the word radiation. "Radiation is basically energy that travels from one point to another. There are many different types of radiation, such as ultraviolet radiation from the sun," Karipidis explained.

Image source: Pixabay

Karipidis also said that we are always exposed to low levels of radio waves in our daily lives, and although the radiation exposure from mobile phones is low, because mobile phones are often used close to the head, it is much higher than the exposure from any other source of radio equipment. So many people are beginning to worry about this issue.

Some early studies have shown that using a mobile phone close to the head for a long time may be associated with the development of brain cancer, and the World Health Organization's International Agency for Research on Cancer (IARC) has also designated the radio frequency electromagnetic fields from mobile phones as a possible carcinogenic risk.

However, on the one hand, the design of these early studies often has flaws. For example, when doing comparative surveys, people without tumors will provide normal information, but those with tumors tend to over-report their electromagnetic radiation exposure. On the other hand, IARC's classification of carcinogenic risks has also caused confusion to the public. When a substance or behavior is considered to have a possible carcinogenic risk, it may not be that serious. In IARC's classification of different levels of cancer risk, carcinogens classified as "confirmed" are high carcinogenic risk factors with definite evidence, such as smoking. And those "possible" carcinogens often mean a lack of sufficient evidence.

In 2011, when the World Health Organization designated radiofrequency electromagnetic fields as a possible carcinogen, hundreds of other substances or behaviors were also given that status because the evidence was inconclusive, such as aloe vera, pickles and working in a dry cleaner.

Since then, more studies have begun to look at the link between radiofrequency electromagnetic fields and diseases such as cancer. In 2019, the World Health Organization commissioned several systematic reviews to further study the health effects of radio waves. This led to the latest study mentioned above.

Karipidis and his colleagues are not done with their research, and are now conducting a second part of their study, which will analyze the association between cell phone use and other types of cancer, such as non-Hodgkin's lymphoma. Karipidis said, "Concerns surrounding the link between cancer and cell phones should be calmed, but as technology develops, it is important to continue research."

Image source: Pixabay

In fact, in addition to the research commissioned by the WHO on the link between radiofrequency electromagnetic fields and common cancers, it has also conducted research on the impact on fertility. However, in a systematic review commissioned by the WHO, researchers found no evidence of a link between mobile phone use and male fertility, such as decreased sperm count.

However, in another systematic review commissioned by the WHO, researchers found that mobile phone use was associated with changes in female fertility in some cases, such as affecting the birth weight of newborns. Of course, it should be noted that this association only occurred when the exposure to radio waves was far above the safe limit.

The relationship between mobile phone radiation and cancer and various diseases is an important public health issue of concern to modern society. With the deepening of scientific research, we now have more data and evidence to answer this question. The results of the latest research show that there is no significant correlation between mobile phone radiation and brain cancer, which undoubtedly provides us with greater psychological comfort in our daily use of mobile phones, but this does not mean that mobile phone radiation is completely harmless.

For example, other studies have found that mobile phone radiation may cause a certain degree of "thermal effect", that is, under high-intensity radiation, the temperature of the skin close to the phone may rise slightly. In extreme cases, this thermal effect may cause a slight temperature change in local tissues, but this change is usually not enough to have a significant impact on health. Under normal use, the temperature rise caused by mobile phone radiation is usually negligible.

However, the development of science is endless. In the future, as research methods advance and data accumulate, we may have a deeper understanding of the health effects of mobile phone radiation. Before that, we should adopt a scientific and rational attitude to avoid unnecessary panic caused by misleading information.

If you are still worried, you can take some measures to make yourself feel more at ease. For example, reduce the time you carry your phone close to you; switch to speaker mode when you are on a long call; keep your phone signal strong, because when the signal is weak, the phone will increase the transmission power to maintain the connection, which may increase the radiation.

Even if we no longer have to worry about looking at our phones too much causing cancer or other diseases, we should still manage the frequency and duration of our phone use. After all, being immersed in our phones all day is bad for our eyes and family relationships.

Acknowledgements: We would like to thank Professor Wang Chenguang for reviewing and revising this paper.

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