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1991.02.19 :  Study -- Fluoride and Cancer

Contact:  Bill Grigg (202) 245-6867 (Home) (301) 652-1864   
February 19, 1991

     The U.S. Public Health Service today reported that its year-
long investigation has found no evidence establishing an
association between fluoride and cancer in humans.
       As head of the Public Health Service, HHS Assistant
Secretary for Health James O. Mason, M.D., requested the study last
February because of a preliminary finding of a rare cancer in four
male test rats in groups fed high doses of fluoride over their
lifetimes.  
       In releasing the study today, Dr. Mason said, "If fluoride
presents any risks to the public at the levels to which the vast
majority of us are exposed, those risks are so small that they have
been impossible to detect in the epidemiological studies to date. 
In contrast, the benefits are great and easy to detect."  
       The study once again confirmed that fluoride in water plays
a central role in preventing tooth decay, thereby reducing
abscesses and extractions and providing "improved health" to all,
"especially poor children."  Although other factors may have been
at work too, the average child today has just over three tooth
surfaces affected by decay.  Before fluoridation in the mid-1940s,
a child of 6 to 15 might have 10 tooth surfaces affected.  
       Dr. Mason recommended that municipalities "continue the
addition of fluorides to water supplies wherever it is deficient.
       "However," he said, "more is not necessarily better. 
Especially in those areas of the United States where fluorides are
naturally present at higher levels than recommended levels, kids do
not need additional systemic fluoride and risk a discoloration, or
mottling, of the teeth."

       The report says that this mottling, called dental fluorosis,
has increased in some parts of the United States in recent years.

       The PHS study found no confirmation in epidemiological
studies of the "equivocal" (or uncertain) finding of osteosarcoma
in four male rats (one of 50 given water containing 100 ppm sodium
fluoride and three of 80 given water containing 175 ppm) over their
lifetimes during a research project of the National Toxicology
Program at Research Triangle Park, N.C.  The finding also was not
observed among female rats or mice of either gender.  The reviewers
said the NTP study and another long-range animal study "fail to
establish an association between fluoride and cancer."      

       In deciding there was no human cancer association shown, the
PHS group reviewed the results of more than 50 human epidemiology
studies that have been produced over the past 40 years.  These
include new studies of bone cancer and other malignancies conducted
for this study by the National Cancer Institute, a part of the
National Institutes of Health.  The report concluded that optimal
fluoridation of drinking water "does not pose a detectable cancer
risk to humans."  There are about 750 cases of osteosarcoma, a rare
form of bone cancer, in Americans each year.  Although the number
appears to have increased, no association was found to the onset of
fluoridation.

       The report said research has also failed to show a link
between fluoride and Down Syndrome or problems of the
gastrointestinal, genito-urinary and respiratory systems.  

       To prevent dental fluorosis and "in accordance with the
prudent health practice of using no more than the amount necessary
to achieve a desired effect," the report recommends: 

       -- that dentists and physicians prescribe fluoride dietary
supplements only if they are certain that the home water supply is
deficient in fluoride.

       -- that parents instruct children to rinse carefully after
brushing and not to swallow fluoride-containing toothpaste.  More
than 90 percent of all toothpaste now contains fluoride.    PHS'
report also urges consumers and health professionals to become more
aware of the fluoride levels in their drinking water, whether
naturally fluoridated or added in a water treatment plant.  

       -- that scientific conferences be held to develop more
detailed guidance to the public about what the total level of
fluoride exposure should be from all sources, not just drinking
water, and that the Environmental Protection Agency then review its
regulations on naturally occurring fluoride in drinking water.  EPA
currently recommends that water supplies, for fluorosis-prevention,
contain no more than 2 ppm in water, which is slightly higher than
0.7 to 1.2 ppm levels reached in optimal fluoridation at water
plants.  EPA requires that fluoride not exceed 4 ppm.   

       The study found conflicting epidemiological evidence on the
role of fluoride in strengthening or weakening bone.  Fluoride
treatments are approved in Europe for osteoporosis, and therapies
of 15 to 25 milligrams per day (plus calcium and Vitamin D) were
recommended, with careful monitoring for side effects, by an
International Workshop on Fluoride and Bone in 1988.  However, the
report cites two more recent U.S. studies that show no clear
benefit from high doses of fluoride and, indeed, indicate some
increases in non-vertebral fractures.  In addition, a Food and Drug
Administration advisory panel concluded in 1989 that fluoride was
not shown to be effective in reducing fractures accompanying
osteoporosis.  

       PHS said its review was the most comprehensive ever focused
by the federal government on fluorides.  The review was conducted
under the direction of an ad hoc subcommittee of the Committee to
Coordinate Environmental and Health Related Programs, which is made
up of agency heads and selected representatives from throughout the
Public Health Service.  The study was headed by Frank E. Young,
M.D., Ph.D., Deputy Assistant Secretary for Health, Science and
Environment.

       Scientists from these Public Health Service agencies
participated in the review: the National Institutes of Health and
its components National Library of Medicine, National Institute for
Arthritis and Musculoskeletal and Skin Diseases, National
Institute of Child Health and Human Development, National Cancer
Institute, National Institute of Environmental Health Sciences and
National Institute of Dental Research; the Food and Drug
Administration's National Center for Toxicological Research,  the
Health Resources and Services Administration, the Agency for Toxic
Substances and Disease Registry, and the Centers for Disease
Control, its Center for Environmental Health and Injury Control,
Center for Prevention Services and National Center for Health
Statistics.  

       Because fluoride is a common mineral in the earth, virtually
all water contains some fluoride, but the amount varies from a
trace that has little or no effect on the teeth to considerably
more than the level reached by fluoridation.  More than half of all
Americans live in areas where water is fluoridated to bring it up
to the levels considered optimal for dental health.   


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