In 1994, the National Cancer Institute (NCI) began a comprehensive study
on the causes of brain tumors. The impetus for the study grew out of public
concern about cellular telephone use and adult brain tumors which led Congress
in 1993 to urge NCI to conduct the study. As the study continues, more risk factors are identified. The information below has been newly updated as of November, 2000.
Because the causes of brain tumors are largely unknown, the study is
evaluating a wide range of environmental, lifestyle, and genetic factors,
in addition to cellular phone use. These include:
Occupational exposures, such as solvents, pesticides, and electromagnetic
fields (EMFs) from electrical machinery;
Family history of cancer;
Dietary factors, including processed meats, artificial sweeteners, and
vitamin and mineral supplements;
Medical history, such as head trauma and radiation exposures;
The study includes approximately 800 brain tumor cases and 800 controls
(people without brain tumors) from three medical institutions: St. Joseph's
Hospital and Medical Center in Phoenix; Brigham and Women's Hospital in
Boston; and Western Pennsylvania Hospital in Pittsburgh. The controls were
admitted to the same hospitals as the cases for treatment of a variety
of non-cancerous conditions. Data collection began in 1994 and was completed
Reproductive history and hormone use; and
Because of intense public interest, the first portion of the NCI study
to be published will address cell phone use and brain tumor risk. Publication
is expected by the end of this year. The principal investigators are Peter
D. Inskip, Sc.D., and Martha S. Linet, M.D., from NCI's Division of Cancer
Epidemiology and Genetics in Bethesda, Md.
The microwave radiation exposures from cellular phones described in
this study occurred between the mid-l980s, when cellular phone use began,
through approximately 1998, when the NCI study ended. One of the limitations
of the NCI study is that the explosion in cellular phone use occurred
after the beginning of the study, and relatively few study participants had
used a cellular phone for a long time. In addition, study participants used primarily
analogue phones while digital phones, which operate at a different frequency and power, are
more commonly used today.
A Swedish cell phone study by Hardell et al (see below) involving 233
cases and 466 controls was published this year and found no overall increased
risk for brain tumors associated with exposure to cellular phones. Another
study, sponsored by the American Health Foundation involving 469 cases
and an equal number of controls, has been submitted for publication. Both
cover approximately the same time period as the NCI study. A multi-center
international cell phone study sponsored by the International Agency for
Research on Cancer, part of the World Health Organization, began data collection
early this year and is expected to be completed in 2004.
Additional cell phone studies have addressed other possible health effects,
such as motor vehicle accidents and interference with cardiac pacemakers.
Publication of the other portions of the NCI brain tumor study will
occur over the next several years.
Publications related to cellular phones and brain tumors:
Inskip PD, Hatch EE, Stewart PA, et al. Study design for a case-control
investigation of cellular telephones and other risk factors for brain tumours
in adults. Radiation Protection Dosimetry 1999;86:45.
Hardell L, Nasman A, Pahlson A, et al. Use of cellular telephones and
the risk for brain tumours: A case-control study. Int J Oncol 1999;15:113-116.
Rothman KJ, Chou CK, Morgan R, et al. Assessment of cellular telephone
and other radio frequency exposures for epidemiologic research. Epidemiology
Hietanen M, Kovala T, Hamalainen AM. Human brain activity during exposure
to radio frequency fields emitted by cellular phones. Scand J Work Environ
Publications related to cell phones and other health risks:
Redelmeier DA, Tibshirani RJ. Association between cellular telephone
calls and motor vehicle collisions. N Engl J Med 1997;336:453-8.
Dreyer NA, Loughlin JE, Rothman KJ. Cause-specific mortality in cellular
telephone users. JAMA 1999;282:1814-6.