WHY I CHANGED MY MIND ABOUT WATER FLUORIDATION
Based on new research, a former fluoridation proponent changes his
opinion about the alleged safety and benefits of water fluoridation
by JOHN COLQUHOUN, Perspectives in
Biology and Medicine, 41, 1, Autumn 1997
Former Advocate
To
explain how I came to change my opinion about water fluoridation, I must go
back to when I was an ardent advocate of the procedure. I now realize that I
had learned, in my training in dentistry, only one side of the scientific
controversy over fluoridation. I had been taught, and believed, that there was
really no scientific case against fluoridation, and that only misinformed lay
people and a few crackpot professionals were foolish enough to oppose it. I
recall how, after I had been elected to a local government in Auckland (New
Zealand's largest city, where I practised dentistry for many years and where I
eventually became the Principal Dental Officer) I had fiercely — and, I now
regret, rather arrogantly — poured scorn on another Council member (a lay
person who had heard and accepted the case against fluoridation) and persuaded
the Mayor and majority of my fellow councillors to agree to fluoridation of our
water supply.
A
few years later, when I had become the city's Principal Dental Officer, I
published a paper in the New Zealand Dental Journal that reported how
children's tooth decay had declined in the city following fluoridation of its
water, to which I attributed the decline, pointing out that the greatest
benefit appeared to be in low-income areas [1]. My duties as a public servant
included supervision of the city's school dental clinics, which were part of a
national School Dental Service which provided regular six-monthly dental
treatment, with strictly enforced uniform diagnostic standards, to almost all
(98 percent) school children up to the age of 12 or 13 years. I thus had access
to treatment records, and therefore tooth decay rates, of virtually all the
city's children. In the study I claimed that such treatment statistics
"provide a valid measure of the dental health of our child
population" [1]. That claim was accepted by my professional colleagues,
and the study is cited in the official history of the New Zealand Dental
Association [2].
INFORMATION CONFIDED
I
was so articulate and successful in my support of water fluoridation that my
public service superiors in our capital city, Wellington, approached me and
asked me to make fluoridation the subject of a world study tour in 1980 — after
which I would become their expert on fluoridation and lead a campaign to
promote fluoridation in those parts of New Zealand which had resisted having
fluoride put into their drinking water.
Before
I left on the tour my superiors confided to me that they were worried about
some new evidence which had become available: information they had collected on
the amount of treatment children were receiving in our school dental clinics
seemed to show that tooth decay was declining just as much in places in New
Zealand where fluoride had not been added to the water supply. But they felt
sure that, when they had collected more detailed information, on all children (especially the oldest
treated, 12-13 year age group) from all
fluoridated and all nonfluoridated
places [3] — information which they would start to collect while was I away on
my tour — it would reveal that the teeth were better in the fluoridated places:
not the 50 to 60 percent difference which we had always claimed resulted from
fluoridation, but a significant difference nonetheless. They thought that the
decline in tooth decay in the nonfluoridated places must have resulted from the
use of fluoride toothpastes and fluoride supplements, and from fluoride
applications to the children's teeth in dental clinics, which we had started at
the same time as fluoridation. Being a keen fluoridationist, I readily accepted
their explanation. Previously, of course, we had assured the public that the
only really effective way to reduce tooth decay was to add fluoride to the
water supply.
WORLD STUDY TOUR
My
world study tour took me to North America, Britain, Europe, Asia, and Australia
[4]. In the United States I discussed fluoridation with Ernest Newbrun in San
Francisco, Brian Burt in Ann Arbor, dental scientists and officials like John
Small in Bethesda near Washington, DC, and others at the Centers for Disease
Control in Atlanta. I then proceeded to Britain, where I met Michael Lennon,
John Beale, Andrew Rugg-Gunn, and Neil Jenkins, as well as many other
scientists and public health officials in Britain and Europe. Although I
visited only profluoridation research centers and scientists, I came across the
same situation which concerned my superiors in New Zealand. Tooth decay was
declining without water fluoridation. Again I was assured, however, that more
extensive and thorough surveys would show that fluoridation was the most
effective and efficient way to reduce tooth decay. Such large-scale surveys, on
very large numbers of children, were nearing completion in the United States,
and the authorities conducting them promised to send me the results.
LESSON FROM HISTORY
I
now realize that what my colleagues and I were doing was what the history of
science shows all professionals do when their pet theory is confronted by
disconcerting new evidence: they bend over backwards to explain away the new
evidence. They try very hard to keep their theory intact — especially so if
their own professional reputations depend on maintaining that theory. (Some
time after I graduated in dentistry almost half a century ago, I also graduated
in history studies, my special interest being the history of science — which
may partly explain my reexamination of the fluoridation theory ahead of many of
my fellow dentists.)
So
I returned from my study tour reinforced in my pro-fluoridation beliefs by
these reassurances from fluoridationists around the world. I expounded these
beliefs to my superiors, and was duly appointed chairman of a national
"Fluoridation Promotion Committee". I was instructed to inform the
public, and my fellow professionals, that water fluoridation resulted in better
children's teeth, when compared with places with no fluoridation.
Surprise: Teeth Better
Without Fluoridation?
Before
complying, I looked at the new dental statistics that had been collected while
I was away for my own Health District, Auckland. These were for all children
attending school dental clinics — virtually the entire child population of
Auckland. To my surprise, they showed that fewer fillings had been required in
the nonfluoridated part of my district than in the fluoridated part. When I
obtained the same statistics from the districts to the north and south of mine
— that is, from "Greater Auckland", which contains a quarter of New
Zealand's population — the picture was the same: tooth decay had declined, but
there was virtually no difference in tooth decay rates between the fluoridated
and non fluoridated places. In fact, teeth were slightly better in the
nonfluoridated areas. I wondered why I had not been sent the statistics for the
rest of New Zealand. When I requested them, they were sent to me with a warning
that they were not to be made public. Those for 1981 showed that in most Health
Districts the percentage of 12- and 13-year-old children who were free of tooth
decay — that is, had perfect teeth — was greater in the nonfluoridated part of
the district. Eventually the information was published [4]. Over the next few
years these treatment statistics, collected for all children, showed that, when
similar fluoridated and non-fluoridated areas were compared, child dental
health continued to be slightly better in the nonfluoridated areas [5,6]. My
professional colleagues, still strongly defensive of fluoridation, now claimed
that treatment statistics did not provide a valid measure of child dental
health, thus reversing their previous acceptance of such a measure when it had
appeared to support fluoridation.
I
did not carry out the instruction to tell people that teeth were better in the
fluoridated areas. Instead, I wrote to my American colleagues and asked them
for the results of the large-scale surveys they had carried out there. I did
not receive an answer. Some years later, Dr John Yiamouyiannis obtained the
results by then collected by resorting to the U.S. Freedom of Information Act,
which compelled the authorities to release them. The surveys showed that there
is little or no differences in tooth decay rates between fluoridated and
nonfluoridated places throughout America [7]. Another publication using the
same database, apparently intended to counter that finding, reported that when
a more precise measurement of decay was used, a small benefit from fluoridation
was shown (20 percent fewer decayed tooth surfaces, which is really less than
one cavity per child) [8]. Serious errors in that report, acknowledged but not
corrected, have been pointed out, including a lack of statistical analysis and
a failure to report the percentages of decay-free children in the fluoridated
and nonfluoridated areas [7].
Other
large-scale surveys from United States, from Missouri and Arizona, have since
revealed the same picture: no real benefit to teeth from fluoride in drinking
water [9, 10]. For example, Professor Steelink in Tucson, AZ, obtained
information on the dental status of all schoolchildren — 26,000 of them — as
well as information on the fluoride content of Tucson water [10]. He found:
"When we plotted the incidence of tooth decay versus fluoride content in a
child's neighborhood drinking water, a positive correlation was revealed. In
other words, the more fluoride a child drank, the more cavities appeared in the
teeth" [11].
From
other lands — Australia, Britain, Canada, Sri Lanka, Greece, Malta, Spain,
Hungary, and India — a similar situation has been revealed: either little or no
relation between water fluoride and tooth decay, or a positive one (more
fluoride, more decay) [12- 17]. For example, over 30 years Professor Teotia and
his team in India have examined the teeth of some 400,000 children. They found
that tooth decay increases as fluoride intake increases. Tooth decay, they
decided, results from a deficiency of calcium and an excess of fluoride [17].
CAUSE OF DECLINE IN TOOTH DECAY
At
first I thought, with my colleagues, that other uses of fluoride must have been
the main cause of the decline in tooth decay throughout the western world. But
what came to worry me about that argument was the fact that, in the
nonfluoridated part of my city, where decay had also declined dramatically,
very few children used fluoride toothpaste, many had not received fluoride
applications to their teeth, and hardly any had been given fluoride tablets. So
I obtained the national figures on tooth decay rates of five-year-olds from our
dental clinics which had served large numbers of these children from the 1930s
on [18]. They show that tooth decay had started to decline well before we had
started to use fluorides (Fig. 1).
Also, the decline has continued after all children had received fluoride all
their lives, so the continuing decline could not be because of fluoride. The
fewer figures available for older children are consistent with the above
pattern of decline [18]. So fluorides, while possibly contributing, could not
be the main cause of the reduction in tooth decay.
So
what did cause this decline, which we find in most industrialized countries? I
do not know the answer for sure, but we do know that after the second world war
there was a rise in the standard of living of many people. In my country there
has been a tremendous increase in the consumption of fresh fruit and vegetables
since the 1930s, assisted by the introduction of household refrigerators [19].
There has also been an eightfold increase in the consumption per head of
cheese, which we now know has anti-decay properties [19, 20]. These nutritional
changes, accompanied by a continuing decline in tooth decay, started before the
introduction of fluorides.
The
influence of general nutrition in protection against tooth decay has been well
described in the past [21], but is largely ignored by the fluoride enthusiasts,
who insist that fluorides have been the main contributor to improved dental
health. The increase in tooth decay in third-world countries, much of which has
been attributed to worsening nutrition [22], lends support to the argument that
improved nutrition in developed countries contributed to improved dental
health.
Flawed Studies
The
studies showing little if any benefit from fluoridation have been published
since 1980. Are there contrary findings? Yes: many more studies, published in
dental professional journals, claim that there is a benefit to teeth from water
fluoride. An example is a recent study from New Zealand, carried out in the
southernmost area of the country [23]. Throughout New Zealand there is a range
of tooth decay rates, from very high to very low, occurring in both fluoridated
and nonfluoridated areas. The same situation exists in other countries. What
the pro-fluoride academics at our dental school did was to select from that southern
area four communities: one nonfluoridated, two fluoridated, and another which
had stopped fluoridation a few years earlier. Although information on decay
rates in all these areas was available to them, from the school dental service,
they chose for their study the one nonfluoridated community with the highest
decay rate and two fluoridated ones with low decay rates, and compared these
with the recently stopped fluoridated one, which happened to have medium decay
rates (both before and after it had stopped fluoridation). The teeth of
randomly selected samples of children from each community were examined. The
chosen communities, of course, had not been randomly selected. The results,
first published with much publicity in the news media, showed over 50 percent
less tooth decay in the fluoridated communities, with the recently
defluoridated town in a "middle" position (see left side of Fig. 2). When I obtained the decay
rates for all children in all the fluoridated and all the nonfluoridated areas
in that part of New Zealand, as well as the decay rates for all children in the
recently defluoridated town, they revealed that there are virtually no
differences in tooth decay rates related to fluoridation (see right side of Fig. 2).
When
I confronted the authors with this information, they retorted that the results
of their study were consistent with other studies. And of course it is true
that many similar studies have been published in the dental professional
literature. It is easy to see how the consistent results are obtained: an
appropriate selection of the communities being compared. There is another
factor: most pro-fluoridation studies (including this New Zealand one) were not
"blind" — that is, the examiners knew which children received
fluoride and which did not. Diagnosis of tooth decay is a very subjective
exercise, and most of the examiners were keen fluoridationists, so it is easy
to see how their bias could affect their results. It is just not possible to
find a blind fluoridation study in which the fluoridated and nonfluoridated
populations were similar and chosen randomly.
EARLY FLAWED STUDIES
One
of the early fluoridation studies listed in the textbooks is a New Zealand one,
the "Hastings Fluoridation Experiment" (the term
"experiment" was later dropped because the locals objected to being
experimented on) [24]. I obtained the Health Department's fluoridation files under
my own country's "Official Information" legislation. They revealed
how a fluoridation trial can, in effect, be rigged [25]. The school dentists in
the area of the experiment were instructed to change their method of diagnosing
tooth decay, so that they recorded much less decay after fluoridation began.
Before the experiment they had filled (and classified as "decayed")
teeth with any small catch on the surface, before it had penetrated the outer
enamel layer. After the experiment began, they filled (and classified as
"decayed") only teeth with cavities which penetrated the outer enamel
layer. It is easy to see why a sudden drop in the numbers of "decayed and
filled" teeth occurred. This change in method of diagnosis was not
reported in any of the published accounts of the experiment.
Another
city, Napier, which was not fluoridated but had otherwise identical drinking
water, was at first included in the experiment as an "ideal control"
— to show how tooth decay did not decline the same as in fluoridated Hastings.
But when tooth decay actually declined more in the nonfluoridated control city
than in the fluoridated one, in spite of the instructions to find fewer
cavities in the fluoridated one, the control was dropped and the experiment
proceeded with no control. (The claimed excuse was that a previously unknown
trace element, molybdenum, had been discovered in some of the soil of the
control city, making tooth decay levels there unusually low [26], but this
excuse is not supported by available information, from the files or elsewhere,
on decay levels throughout New Zealand).
The
initial sudden decline in tooth decay, in the fluoridated city, plus the
continuing decline which we now know was occurring everywhere else in New
Zealand, were claimed to prove the success of fluoridation. These revelations
from government files were published in the international environmental
journal, The Ecologist, and presented
in 1987 at the 56th Congress of the Australian and New Zealand Association for
the Advancement of Science [27].
When
I re-examined the classic fluoridation studies, which had been presented to me
in the text books during my training, I found, as others had before me, that
they also contained serious flaws [28-30]. The earliest set, which purported to
show an inverse relationship between tooth decay prevalence and naturally
occurring water fluoride concentrations, are flawed mainly by their nonrandom
methods of selecting data. The later set, the "fluoridation trials"
at Newburgh, Grand Rapids, Evanston, and Brantford, display inadequate
baselines, negligible statistical analysis, and especially a failure to
recognize large variations in tooth decay prevalence in the control
communities. We really cannot know whether or not some of the tooth decay
reductions reported in those early studies were due to water fluoride.
I
do not believe that the selection and bias that apparently occurred was
necessarily deliberate. Enthusiasts for a theory can fool themselves very
often, and persuade themselves and others that their activities are genuinely
scientific. I am also aware that, after 50 years of widespread acceptance and
endorsement of fluoridation, many scholars (including the reviewers of this
essay) may find it difficult to accept the claim that the original fluoridation
studies were invalid. That is why some of us, who have reached that conclusion,
have submitted an invitation to examine and discuss new and old evidence
"in the hope that at least some kind of scholarly debate will ensue"
[31].
However,
whether or not the early studies were valid, new evidence strongly indicates
that water fluoridation today is of little if any value. Moreover, it is now
widely conceded that the main action of fluoride on teeth is a topical one (at
the surface of the teeth), not a systemic one as previously thought, so that
there is negligible benefit from swallowing fluoride [32].
Harm from Fluoridation
The
other kind of evidence which changed my mind was that of harm from fluoridation. We had always assured the public that there
was absolutely no possibility of any harm. We admitted that a small percentage
of children would have a slight mottling of their teeth, caused by the
fluoride, but this disturbance in the formation of tooth enamel would, we
asserted, be very mild and was nothing to worry about. It was, we asserted, not
really a sign of toxicity (which was how the early literature on clinical
effects of fluoride had described it) but was only at most a slight, purely
cosmetic change, and no threat to health. In fact, we claimed that only an
expert could ever detect it.
HARM TO TEETH
So
it came as a shock to me when I discovered that in my own fluoridated city some
children had teeth like those in Fig. 3. This kind of
mottling answered the description of dental fluorosis (bilateral diffuse
opacities along the growth lines of the enamel). Some of the children with
these teeth had used fluoride toothpaste and swallowed much of it. But I could
not find children with this kind of fluorosis in the nonfluoridated parts of my
Health District, except in children who had been given fluoride tablets at the
recommended dose of that time.
I
published my findings: 25 percent of children had dental fluorosis in
fluoridated Auckland and around 3 percent had the severer (discolored or
pitted) degree of the condition [33]. At first the authorities vigorously
denied that fluoride was causing this unsightly mottling. However, the
following year another Auckland study, intended to discount my finding,
reported almost identical prevalences and severity, and recommended lowering
the water fluoride level to below 1 ppm [34]. Others in New Zealand and the
United States have reported similar findings. All these studies were reviewed
in the journal of the International Society for Fluoride Research [35]. The
same unhappy result of systemic administration of fluoride has been reported in
children who received fluoride supplements [36]. As a result, in New Zealand as
elsewhere, the doses of fluoride tablets were drastically reduced, and parents
were warned to reduce the amount of fluoride toothpaste used by their children,
and to caution them not swallow any. Fluoridationists would not at first admit
that fluoridated water contributed to the unsightly mottling — though later, in
some countries including New Zealand, they also recommended lowering the level
of fluoride in the water. They still insist that the benefit to teeth outweighs
any harm.
WEAKENED BONES
Common
sense should tell us that if a poison circulating in a child's body can damage
the tooth-forming cells, then other harm also is likely. We had always admitted
that fluoride in excess can damage bones, as well as teeth.
By
1983 I was thoroughly convinced that fluoridation caused more harm than good. I
expressed the opinion that some of these children with dental fluorosis could,
just possibly, have also suffered harm to their bones [Letter to Auckland
Regional Authority, Jan. 1984]. This opinion brought scorn and derision: there
was absolutely no evidence, my dental colleagues asserted, of any other harm
from low levels of fluoride intake, other than mottling of the teeth.
Six
years later, the first study reporting an association between fluoridated water
and hip fractures in the elderly was published [37]. It was a large-scale one.
Computerization has made possible the accumulation of vast data banks of
information on various diseases. Hip fracture rates have increased
dramatically, independently of the increasing age of populations. Seven other
studies have now reported this association between low water fluoride levels
and hip fractures [38-44]. Have there been contrary findings? Yes; but most of
the studies claiming no association are of small numbers of cases, over short
periods of time, which one would not expect to show any association [45, 46].
Another, comparing a fluoridated and a nonfluoridated Canadian community, also
found an association in males but not in females, which hardly proves there is
no difference in all cases [47]. Our fluoridationists claim that the studies
which do show such an association are only epidemiological ones, not clinical
ones, and so are not conclusive evidence.
But
in addition to these epidemiological studies, clinical trials have demonstrated
that when fluoride was used in an attempt to treat osteoporosis (in the belief
it strengthened bones), it actually caused more hip fractures [48-52]. That is,
when fluoride accumulates in bones, it weakens them. We have always known that
only around half of any fluoride we swallow is excreted in our urine; the rest
accumulates in our bones [53, 54]. But we believed that the accumulation would
be insignificant at the low fluoride levels of fluoridated water. However,
researchers in Finland during the 1980s reported that people who lived 10 years
or more in that country's one fluoridated city, Kuopio, had accumulated
extremely high levels of fluoride in their bones — thousands of parts per
million — especially osteoporosis sufferers and people with impaired kidney
function [55, 56]. After this research was published, Finland stopped
fluoridation altogether. But that information has been ignored by our
fluoridationists.
BONE CANCER?
An
association with hip fracture is not the only evidence of harm to bones from
fluoridation. Five years ago, animal experiments were reported of a
fluoride-related incidence of a rare bone cancer, called osteosarcoma, in young
male rats [57]. Why only the male animals got the bone cancer is not certain,
but another study has reported that fluoride at very low levels can interfere
with the male hormone, testosterone [58]. That hormone is involved in bone
growth in males but not in females.
This
finding was dismissed by fluoridation promoters as only "equivocal
evidence", unlikely to be important for humans. But it has now been found
that the same rare bone cancer has increased dramatically in young human males — teenage boys aged 9 to 19
— in the fluoridated areas of America but not in the nonfluoridated areas [59].
The New Jersey Department of Health reported osteosarcoma rates were three to
seven times higher in its fluoridated areas than in its nonfluoridated areas
[60].
Once
again, our fluoridationists are claiming that this evidence does not
"conclusively" demonstrate that fluoride caused the cancers, and they
cite small-scale studies indicating no association. One study claimed that
fluoride might even be protective against osteosarcoma [61]; yet it included
only 42 males in its 130 cases, which meant the cases were not typical of the
disease, because osteosarcoma is routinely found to be more common in males.
Also, the case-control method used was quite inappropriate, being based on an
assumption that if ingested fluoride was the cause, osteosarcoma victims would
require higher fluoride exposure than those without the disease. The
possibility that such victims might be more susceptible to equal fluoride
exposures was ignored. All these counter-claims have been subjected to critical
scrutiny which suggests they are flawed [62, 63]. Nonetheless, the pro-fluoride
lobbyists continue to insist that water fluoridation should continue because,
in their view, the benefits to teeth outweigh the possibility of harm. Many
dispute that assessment.
OTHER EVIDENCE OF HARM
There
is much more evidence that tooth mottling is not the only harm caused by
fluoridated water. Polish researchers, using a new computerized method of X-ray
diagnosis, reported that boys with dental fluorosis also exhibit bone structure
disturbances [64]. Even more chilling is the evidence from China that children with
dental fluorosis have on average lower intelligence scores [65, 66]. This
finding is supported by a recently published animal experiment in America,
which showed that fluoride also accumulated in certain areas of the brain,
affecting behavior and the ability to learn [67].
Endorsements Not Universal
Concerning
the oft-repeated observation that fluoridation has enjoyed overwhelming
scientific endorsement, one should remember that even strongly supported
theories have eventually been revised or replaced. From the outset,
distinguished and reputable scientists opposed fluoridation, in spite of
considerable intimidation and pressure [68, 69]. Most of the world has rejected
fluoridation. Only America where it originated, and countries under strong
American influence persist in the practice. Denmark banned fluoridation when
its National Agency for Environmental Protection, after consulting the widest
possible range of scientific sources, pointed out that the long-term effects of
low fluoride intakes on certain groups in the population (for example, persons
with reduced kidney function), were insufficiently known [70]. Sweden also
rejected fluoridation on the recommendation of a special Fluoride Commission,
which included among its reasons that: "The combined and long-term
environmental effects of fluoride are insufficiently known" [71]. Holland
banned fluoridation after a group of medical practitioners presented evidence
that it caused reversible neuromuscular and gastrointestinal harm to some
individuals in the population [72].
Environmental
scientists, as well as many others, tend to doubt fluoridation. In the United
States, scientists employed by the Environmental Protection Agency have
publicly disavowed support for their employer's pro-fluoridation policies [73].
The orthodox medical establishment, rather weak or even ignorant on
environmental issues, persist in their support, as do most dentists, who tend
to be almost fanatical about the subject. In English- speaking countries,
unfortunately, the medical profession and its allied pharmaceutical lobby (the
people who sell fluoride) seem to have more political influence than
environmentalists.
|
REFERENCES
|
|
|
|
FIG. 1. -- 50-year decline in tooth decay of
5-year-olds.
SOURCE. -- Compiled from Health Department
records of 5-year-olds'
tooth decay 1930-1990, fluoridation, and fluoride toothpaste sales.
tooth decay 1930-1990, fluoridation, and fluoride toothpaste sales.
Fig. 2. - Left: results of South Island
dental survey of samples of 5-year-olds from selected areas. See[23].
Right: Results for all 5-year-olds in all nonfluoridated, fluoridated, and defluoridated areas. (School Dental Service records).
Right: Results for all 5-year-olds in all nonfluoridated, fluoridated, and defluoridated areas. (School Dental Service records).
Fig. 3. - Examples of dental fluorosis
in 8- and 9-year old children who grew up in fluoridated Auckland, New Zealand.
at teeth.htm
Reprinted
from PERSPECTIVES IN BIOLOGY AND MEDICINE, published by the University of
Chicago Press, copyright © 1997 by the University of Chicago. All rights
reserved. Permission grant #46850 to Health Action Network Society, June 10,
1998. This text may be used and shared in accordance with the fair use
provisions of US and international copyright law and agreement, and it may be
archived and redistributed in electronic form, provided that this entire
notice, including copyright information, is carried and provided that the
University of Chicago Press is notified and no fee is charged for access.
Archiving, redistribution or republication of this text on other terms, in any
medium, requires both the consent of the author(s) and the University of
Chicago Press.
No comments:
Post a Comment