Base Station Research

 

SFDPH has summarized Ongoing Research studies, Studies and Reviews of the literature and evidence, and Research Agency statements and fact sheets relevant to Mobile Phone Base Stations. This is the Studies and Reviews page.

 

Studies and Reviews of the Literature

 

1. Mobile Phone Base Stations

The mobile phone base station is the antenna and transmitting equipment which both transmits and receives the signal to and from the cell phones. The base station antennas are typically mounted 30 to 90 feet above the ground. The typical public exposure to radio frequency energy from a base station is much less than from the cell phone. This is because of the distance from the body that a cell phone is used versus the distance to the cell base station antenna. The following summarizes studies of the health effects from exposure to mobile base stations.

 

Systematic review on the health effects of exposure to radiofrequency electromagnetic fields from mobile phone base stations (cell antennas).

Method: The World Health Organization (WHO) conducted a systematic search of all peer-reviewed papers published before March 2009. In total, 134 potentially relevant publications were identified; 117 articles were excluded as they were of insufficient quality to meet the inclusion criteria.

Findings: The WHO did not find an association between any health outcome and radiofrequency electromagnetic field exposure from mobile phone base stations (antennas) at levels typically encountered in people's everyday environment. The evidence that no relationship exists between MPBS exposure and acute symptom development can be considered strong according to the GRADE approach because it is based on randomized trials applying controlled exposure conditions in a laboratory.

This work was followed by a 2011 review by the International Agency for Research on Cancer (IARC) which found inadequate evidence of carcinogenicity for environmental exposures associated with wireless telecommunications.

 

Mobile phone base stations and early childhood cancers: case-control study

Method: The United Kingdom Mobile Telecommunications and Health Research (MTHR*) sponsored a large scale study to evaluate the potential relationship between exposure of radio frequency from cell phone base stations during pregnancy and cancer. The study identified about 1400 cases of cancer in children aged up to four years old from across the United Kingdom. Four controls for each case were selected on the basis of sex and date of birth. Exposures were based on both calculations and field measurements for the areas located with 700 meters of the base stations.

Findings: The study found that there is no association between risk of early childhood cancers and estimates of the mother's exposure to mobile phone base stations during pregnancy.

 

*The MTHR was established in the United Kingdom in 2001 as a part of the government's response to the recommendations of the Independent Expert Group on Mobile Phones (Stewart Committee). Over a period of 11 years the program has sponsored 31 research projects which have focused on uncertainties regarding radiofrequency and health effects identified by the committee. The MTHR is run by an independent program management committee made up of specialist including member of the Stewart Committee and the World Health Organizations.

 

2. Mobile Phone Devices

The mobile phone device has been the subject of several large studies and evidence reviews. The following summarizes studies and reviews of the potential for health effects from exposure to mobile and wireless phone devices.

 

International Agency for Research on Cancer (IARC) Evaluation of carcinogenic risks to humans

Method: Working group of 31 scientists from 14 countries evaluated the available literature on; 1) occupational exposures to radar and to microwaves, 2) environmental exposures associated with transmission of signals for radio, television and wireless telecommunication, 3) personal exposures associated with the use of wireless telephones to assess the carcinogenicity of radiofrequency electromagnetic fields. Much of the evidence considered were from the Interphone Study (described below).

Findings: The evidence of carcinogenicity for: 1) occupational exposures to radar and to microwaves and 2) environmental exposures associated with transmission of signals for radio, television and wireless telecommunication, was deemed to be inadequate. This means that the studies evaluated were of insufficient quality, consistency or statistical power to permit a conclusion regarding the presence or absence of a causal association between exposure and cancer, or no data on cancer in humans is available. The evidence of carcinogenicity for: 3) personal exposures associated with the use of wireless telephones was found to also be insufficient for meningioma, parotid-gland tumors, leukemia, lymphoma and other tumors types but was found to be a possible carcinogen to humans for glioma and acoustical neuroma. WHO classified the radiofrequency energy from cell phones as a Group 2B or possible carcinogen for humans. The 2B category means that there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. A 2B classification means that more research is needed in order to determine if radiofrequency energy from cell phones is or is not a cause of glioma and acoustical neuroma.

INTERPHONE Study

The Interphone Study was a very large scale 10 year study involving 13 countries which evaluated the relationship between phone use and many forms of cancer. WHO's International Agency for Research on Cancer (IARC) came to the following conclusions regarding the INTERPHONE Study in their Final Report to the Union for International Cancer Control.

Glioma and meningioma Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation. The possible effects of long‐term heavy use of mobile phones require further investigation.

Acoustic neuroma There was no increase in risk of acoustic neuroma with ever regular use of a mobile phone or for users who began regular use 10 years or more before the reference date. Elevated odds ratios observed at the highest level of cumulative call time could be due to chance, reporting bias or a causal effect. As acoustic neuroma is usually a slowly growing tumour, the interval between introduction of mobile phones and occurrence of the tumour might have been too short to observe an effect, if there is one.

 

Danish Cohort Study

Method: Based on Danes born after 1925 aged 30 years and older. There were 358,403 participants who all reported using cell phones from 1990 – 2007. This extended study allowed the researchers to study people who had used mobile phones for 10 years or more. Poisson regression models adjusted for age, calendar period, education and disposable income. This is the most recent study which is a follow-up to the original study done for the period 1982 -1995 and the second study done from 1996 – 2002.

Findings: This study found no indication of an increased risk of tumors of the central nervous system or temporal gliomas for long term mobile phone users (>10 years).

 

Mobile phone use and glioma risk: comparison of epidemiological study results with incidence trends in the United States

Method: The Intramural Research Program of the National Institutes of Health, and the National Cancer Institute, Division of Cancer Epidemiology and Genetics funded a study to see if the predicted increase in glioma made as the result of the Interphone and Swedish (Hardell) studies was being seen in the population in the United States. Cases of glioma were evaluated between 1997 and 2008.

Findings: Raised risks of glioma with mobile phone use, as reported by one (Swedish) study forming the basis of the IARC's re-evaluation of mobile phone exposure, are not consistent with observed incidence trends in US population date, although the US data could be consistent with the modest excess risks in the Interphone study.

 

Brain cancer incidence trends in relation to cellular telephone use in the United States

Method: The Intramural Research Program of the National Institutes of Health, and the National Cancer Institute, Division of Cancer Epidemiology and Genetics funded a study which examined temporal trends in brain cancer incidence rates in the United States, using data collected by the Surveillance, Epidemiology, and End Results (SEER) Program. This study covered cancer cases for the years 1992 – 2006.

Findings: No increases were apparent for temporal or parietal lobe cancers, or cancers of the cerebellum, which involve the parts of the brain that would be more highly exposed to radiofrequency radiation from cellular phones. Frontal lobe cancer rates also rose among 20–29-year-old males, but the increase began earlier than among females and before cell phone use was highly prevalent. Overall, these incidence data do not provide support to the view that cellular phone use causes brain cancer.

 

CEFALO Study

Method: The CEFALO study was an international case-control study examining the association between mobile phone use and the risk of brain tumors in children and adolescents. The study was conducted in Switzerland, Denmark, Norway and Sweden. All children and adolescents aged 7 to 19 years and diagnosed with a brain tumor between2004 and 2008 were eligible for the study. For each patient, two controls of the same age, gender and region of residence were randomly selected from population registries. Overall, 352 patients and 646 controls took part in the study.

Findings: The results of the CEFALO study do not suggest a causal association between mobile phone use among children or adolescents and the brain tumor risk. However, since the duration and intensity of use was relatively low in our sample we were not able to evaluate the brain tumor risk regarding intensive long term mobile phone use.