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Cell Phones and Cancer Risk
Why is there concern that cell phones may cause cancer or other health problems?
There are three main reasons why people are concerned that cell phones (also known as “mobile” or “wireless” telephones) might have the potential to cause certain types of cancer or other health problems:
Cell phones emit radiofrequency radiation (radio waves), a form of non-ionizing radiation, from their antennas. Parts of the body nearest to the antenna can absorb this energy.
The number of cell phone users has increased rapidly. There were over 400 million cell phone subscribers in the United States in 2017, according to the Cellular Telecommunications and Internet AssociationExit Disclaimer. Globally, there are more than 5 billion cell phone usersExit Disclaimer.
Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. Because of changes in cell phone technology and increases in the number of base stations for transmitting wireless signals, the exposure from cell phone use—power output—has changed, mostly lowered, in many regions of the United States (1).
The NCI fact sheet Electromagnetic Fields and Cancer includes information on wireless local area networks (commonly known as Wi-Fi), cell phone base stations, and cordless telephones.
What is radiofrequency radiation and how does it affect the human body?
How is radiofrequency radiation exposure measured in epidemiologic studies?
What has epidemiologic research shown about the association between cell phone use and cancer risk?
What are the findings from experimental studies?
Why are the findings from different studies of cell phone use and cancer risk inconsistent?
A few studies have shown some evidence of statistical association of cell phone use and brain tumor risks in humans, but most studies have found no association. Reasons for these discrepancies include the following:
Recall bias, which can occur when data about prior habits and exposures are collected from study participants using questionnaires administered after diagnosis of a disease in some of the participants. It is possible that study participants who have brain tumors may remember their cell phone use differently from individuals without brain tumors. Many epidemiologic studies of cell phone use and brain cancer risk lack verifiable data about the total amount of cell phone use over time. In addition, people who develop a brain tumor may have a tendency to recall cell phone use mostly on the same side of the head where their tumor was found, regardless of whether they actually used their phone on that side of the head a lot or only a little.
Inaccurate reporting, which can happen when people say that something has happened more or less often than it actually did. People may not remember how much they used cell phones in a given time period.
Morbidity and mortality among study participants who have brain cancer. Gliomas are particularly difficult to study, for example, because of their high death rate and the short survival of people who develop these tumors. Patients who survive initial treatment are often impaired, which may affect their responses to questions. Furthermore, for people who have died, next-of-kin are often less familiar with the cell phone use patterns of their deceased family member and may not accurately describe their patterns of use to an interviewer.
Participation bias, which can happen when people who are diagnosed with brain tumors are more likely than healthy people (known as controls) to enroll in a research study. Also, controls who did not or rarely used cell phones were less likely to participate in the Interphone study than controls who used cell phones regularly. For example, the Interphone study reported participation rates of 78% for meningioma patients (range among the individual studies 56–92%), 64% for glioma patients (range 36–92%), and 53% for control subjects (range 42–74%)