by Paul Connett
Dean claimed that he limited the cities to those for which he had evidence that the water supply had been a constant source of natural fluoride for twenty years or more. However, according to Dr. Fred Exner, a well-known radioloCAF gist and prominent critic of fluoridation, during cross-examination in court (Schuringa v. Chicago, 1960), Dean admitted that some of the cities did not meet that criterion. 6
Figure 7. 1. Dean’s twenty-one-city graph. The original caption read, “Relation between the amount of dental caries (permanent teeth) observed in 7257 selected 12–14 year old white school children of 21 cities of 4 states and the fluoride (F) content of the public water supply. ” Source: Adapted from Dean, Arnold, and Elvove, 1942. 5
The late Rudolf Ziegelbecker, an Austrian statistician, pursued this issue. When he added in all the data he could find from the United States and Europe that compared prevalence of tooth decay with natural fluoride levels in the water, the inverse relationship reported by Dean was absent (see figure 7. 2). However, when he examined the same data for dental fluorosis, he found a robust direct relationship—that is, as the level of fluoride in the water increased, so did the prevalence of dental fluorosis (see figure 7. 3). One relationship (between fluoride levels and dental fluorosis) holds up over the “background noise”; the other (between fluoride levels and dental decay) does not. 7
In a subsequent study Ziegelbecker and his son examined tooth decay data collected by the World Health Organization (WHO) in several individual countries, and again they found no relationship between tooth decay and levels of natural fluoride in drinking water. 9 Ziegelbecker Senior further elaborated on his critique of Dean’s twenty-one-city study and the practice of fluoridation in general in a submission he made to Codex Alimentarius in 2003. ”10
Figure 7. 2. Ziegelbecker’s plot of prevalence of tooth decay versus water fluoride levels. Tooth decay is plotted as the probit values of the percentages of the average DMFT in each community (the Z scale). The probit transformation is a standard procedure for making percentage data linear and more amenable to statistical analysis. The fluoride water levels (X ppm) in each community are plotted on a logarithmic scale as log (X + 0. 3). The addition of 0. 3 is Ziegelbecker’s adjustment for other sources of fluoride in addition to water. Source: Reproduced from Ziegelbecker, 1981. 8
The Early Trials
The trials conducted between 1945 and 1955 in the United States and Canada and a little later in New Zealand, which helped to consolidate the argument that fluoridation reduces tooth decay, have been heavily criticized. In those trials, pairs of cities were chosen; in one city of each pair sodium fluoride was added to the water to a level of 1 ppm, and in the other city (the control city) no addition was made. In one trial (in Brantford, Ontario) two controls were used: One control city (Sarnia, Ontario) had no fluoride added, and the other (Stratford, Ontario) had natural levels of fluoride at 1. 3 ppm. In two of the trials (those in Grand Rapids, Michigan, and Hastings, New Zealand) the control cities (Muskegon and Napier, respectively) were dropped long before the trials were due to end. The authors of this book have not studied in depth all the many reports published during those trials, but people who have done so have found many weaknesses in the methodologies used and the poor choice of control communities. 12–16 According to Dr. Hubert Arnold, a statistician from the University of California at Davis, the early fluoridation trials “are especially rich in fallacies, improper design, invalid use of statistical methods, omissions of contrary data, and just plain muddleheadedness and hebetude. ”17
Figure 7. 3. Ziegelbecker’s plot of the prevalence of dental fluorosis versus water fluoride levels. Dental fluorosis is plotted as the probit values of the percentages of the children in each community with this condition (the Z scale). The scale used in the horizontal axis is explained in the legend to Figure 7. 2. Source: Reproduced from Ziegelbecker, 1981. 11
In chapter 8 we discuss many factors that affect tooth decay. These include income level, ethnicity, diet, other minerals in the water, local soil and food, dental education level, and the quality of dental services available. Further complicating the issue is maintaining a consistent diagnosis of tooth decay over time and between the exposed and control communities. Many of these factors were not controlled very carefully, if at all, in the early trials, and that led to exaggerated claims of reduction in tooth decay in the conclusions of those trials.
Examples of Poor Methodology
As mentioned previously, in two trials, the control communities (Muskegon, Michigan, and Napier, New Zealand) were fluoridated before the trial was completed, so the reductions in tooth decay claimed were based on a before-and-after assessment of the fluoridated community and not a comparison with the non-fluoridated community. The reductions in the prevalence of tooth decay ascribed to fluoridation would have been negated if there had been comparable reductions in the non-fluoridating community over the same period of time.
Furthermore, when the Grand Rapids–Muskegon trial began in Michigan in 1945, children from all seventy-nine schools in Grand Rapids (the fluoridated city) were examined. By 1949, however, examiners were observing children from only twenty-five of those schools. Meanwhile, in Muskegon (the non-fluoridated control city), children from all the schools were still being examined.
Another example of inconsistency in sampling size is provided by the fact that when the Grand Rapids study commenced, the number of twelve- to sixteen-year-olds examined was 7, 661, but by the final year of the study, the number being studied had dropped to 1, 031. 18
Along with these changes in sampling methods, the Grand Rapids study employed multiple examiners to assess the children’s teeth. But at the time, studies had already shown that there is considerable variability among dentists’ assessments of tooth decay. 19, 20 Dr. Philip Sutton, who authored two monographs on this subject, 21, 22 was senior research fellow in the Department of Oral Medicine and Surgery at the Dental School of the University of Melbourne, Australia. His criticisms of these early trials have never been successfully refuted by proponents, even though they have tried. Some of the efforts to critique his work, and Sutton’s responses, were published in a book titled The Greatest Fraud: Fluoridation shortly before he died, in 1996. 23
The Newburgh-Kingston Trial
There are three very interesting extra pieces of information about the Newburgh versus Kingston trial. The first is that even while the original researchers were claiming the benefits of fluoridation, a report emerged that far more tooth defects were being observed in fluoridated Newburgh than in unfluoridated Kingston. In a letter dated October 26, 1954 (over nine years into the trial), John Forst, MD, of the New York State Education Department, reported to Dr. James Kerwin, of the New Jersey Department of Health, that in unfluoridated Kingston 41. 6 percent (2, 209 out of 5, 303 pupils) had defects, with 29. 2 percent receiving treatment, compared with 63. 2 percent (3, 139 out of 4, 959) that had defects, with 41. 7 percent receiving treatment, in fluoridated Newburgh. 24
The second interesting piece of information is that in the intervening years since 1955 the control community of Kingston has never been fluoridated. This has allowed researchers to continue to compare tooth decay in the two communities over a period of fifty years. Over this period the purported difference in tooth decay reported in 1955 between the fluoridated and non-fluoridated communities has disappeared. The latest study, giving rise to two separate papers (published in 1998), indicates that the teeth of the children in unfluoridated Kingston are slightly better than those in fluoridated Newburgh. 26, 27 In figure 7. 4 we have plotted the reported tooth decay for children ages seven to fourteen, comparing children in fluoridated Newburgh and unfluoridated Kingston, in the comparisons conducted in 1945, 1955, 1986, and 1995, as graphically summarized by Kumar and Green. 28
Figure 7. 4. Plots of tooth decay (measured as DMFT = decayed, missing, and filled permanent teeth) of seven- to fourteen-year-old lifelong residents in Newburgh (fluoridated) and Kingston (unfluoridated)
, New York, published in 1945, 1955, 1986, and 1995, respectively. Source: Plots derived from figure 1 in Kumar and Green, 1998. 25
The third interesting piece of information is that the Newburgh-Kingston trial was closely monitored by Dr. Harold Hodge, chief toxicologist for the Manhattan Project. 29 Apparently, the team that was developing the atomic bomb was very interested in monitoring fluoride’s low-level toxic effects on children. We discuss some of the health effects observed in this trial, including the earlier onset of menstruation in young girls in fluoridated Newburgh, in chapter 10, and we say more about Harold Hodge’s long history of involvement in the promotion of fluoridation in chapters 9 and 10.
The Hastings-Napier Trial
The Hastings-Napier trial was begun in 1954 and was used to promote fluoridation successfully throughout New Zealand. However, this trial has since been shown to be fraudulent. 30–32 The control community (Napier) was dropped two years after the trial began, and the huge drop in tooth decay found in Hastings was found to be due to a change in the methodology used to determine what constituted tooth decay between when the study started and when it ended. The change in methodology was not acknowledged by the authors when they published their reports. 33–38
Summary
There are several reasons to doubt the validity of the Dean et al. study on the relationship between caries incidence and the fluoride content of water. Subsequently, Ziegelbacker found no relationship, such as claimed by Dean, although there was a strong relationship between fluoride concentration and the incidence of fluorosis. Many serious flaws have been identified in the early trials of fluoridation, on which the modern dogma of fluoridation’s safety and effectiveness is built. Subsequent developments in tooth decay in the towns of Newburgh and Kingston, New York, in the years since 1955 (the year when the study there concluded) put into question the benefits claimed in 1955.
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8 •
Key Modern Studies
In the history of fluoridation a major development occurred in 1980. This was the year when Dr. John Colquhoun was sent by his superiors in New Zealand on a four-month world tour to investigate tooth decay on several continents. He expected to bring back with him evidence that would prove, once and for all, that fluoridation worked. He failed to do so.
Colquhoun’s Fluoridation Activities
In the 1960s and 1970s John Colquhoun was the principal dental officer for Auckland, New Zealand’s largest city. Both as a dental officer and as a city councilor, he enthusiastically and successfully promoted fluoridation throughout the country. He poured scorn on one particular councilor who opposed the measure—for which Colquhoun later apologized.
On his 1980 world tour, which took him to Australia, Asia, North America, and Europe, pro-fluoridation dental researchers told Colquhoun in private that they were not finding the difference in tooth decay between fluoridated and non-fluoridated communities that they had expected; in fact, they were finding very little difference at all.
When Colquhoun returned to New Zealand, he looked at the complete record of tooth decay in the country. At that time, under the New Zealand National Health Service, all five-year-olds and twelve-year-olds had their teeth examined. He found no difference in tooth decay between the fluoridated and non-fluoridated cities. If anything, the teeth were slightly better in the non-fluoridated communities.
After Colquhoun’s assistants reported to him the extensive amount of dental fluorosis occurring in fluoridated Auckland, he made fluoridation’s ineffectiveness public. To his enormous credit he spent the rest of his life trying to undo the damage he had done promoting fluoridation, by reversing his position and opposing the practice in any scientific way he could. Author Paul Connett interviewed Colquhoun on videotape in Auckland in 1997, shortly before Colquhoun died, and found that interviewing this soft-spoken but courageous man was a humbling experience. 1 Colquhoun wrote up his findings in several published papers. 2–7 After he retired he obtained a PhD, and his research thesis examined the history of fluoridation in New Zealand. 8 He argued that New Zealand’s dental education program to reduce tooth decay was superior to the use of water fluoridation for the same purpose. He offered Thomas Kuhn’s famous analysis, The Structure of Scientific Revolutions, 9 to explain the reluctance of the New Zealand dental community to change its outlook on fluoridation’s safety and effectiveness. In his thesis, Colquhoun also exposed the rigged nature of the Hastings-Napier fluoridation trial (discussed in chapter 7).
Colquhoun summarized his evolution on this issue in a journal article published in 1997 titled “Why I Changed My Mind about Fluoridation. ”10 Two fluoridation proponents responded to Colquhoun’s arguments in a later issue of the same journal, with an article titled “Why We Have Not Changed Our Minds about the Safety and Efficacy of Water Fluoridation: A Response to John Colquhoun. ” They wrote, “Colquhoun, like many opponents of fluoridation, subscribes to the conspiracy theory, according to which the government, health authorities, and the dental profession are trying to foist water fluoridation on an unsuspecting public. ”11
Leverett 1982
In the 1980s, articles began to appear in major publications like Science and Nature confirming what Colquhoun had found out privately. These articles pointed out that the prevalence of tooth decay was falling as fast in non-fluoridated communities as in fluoridated ones. Dennis Leverett reviewed many of these studies in Science in 1982. He noted:
Within the past 2 or 3 years there has been increasing evidence from several developed nations of a drop in the prevalence of dental caries which cannot be attributed directly to intentional fluoride use. The data are becoming available as epidemiologists and clinical researchers review the patterns of dental caries prevalence in communities that do not have fluoridated water. The data cover children from the ages of 5 to 17 for various periods of up to 30 years; caries reductions as high as 60 per cent have been observed. 12
Leverett cited at least nine studies that showed a decline in caries prevalence in communities without fluoridated water and speculated that the reductions were due to “an increase in fluoride in the food chain, especially from the use of fluoridated water in food processing, increased use of infant formulas with measurable fluoride content, and even unintentional ingestion of fluoride dentifrices. ”13
Diesendorf 1986
Mark Diesendorf published “The Mystery of Declining Tooth Decay” in Nature in 1986. 14 As did Leverett, Diesendorf reported little difference in tooth decay between fluoridated and non-fluoridated communities. He rejected Leverett’s hypothesis that the drop in tooth decay in non-fluoridated areas was due to the ingestion of fluoride from other sources, because, he said, “the food processing pathway is unlikely to be significant in Western Europe where there is hardly any fluoridation. ”15 He suggested, “The main causes of the observed reductions in caries are changes in dietary patterns, possible changes in the immune status of populations and, under some circumstances, the use of topical fluorides. ”16
Diesendorf concluded his article with this comment: “Perhaps the real mystery of declining tooth decay is why so much effort has gone into poor quality research on fluoridation, instead of on more fundamental questions of diet and immunity. ”17
It is worth noting that Diesendorf’s background was not in dentistry but in theoretical physics. Indeed, he had previously published in Nature on that subject. Today he is better known in Australia for his work on alternative energy sources. 18
Gray 1987
Another dental professional who questioned fluoridation’s effectiveness was A. S. Gray, who reviewed the tooth-decay figures in British Columbia and other parts of Canada. According to Gray, those figures indicated the following:
DMF rates in children are falling drastically in non-fluoridated areas as well as fluoridated areas. The current statements of our profession in support of fluoridation do not appear to take these changes into account. It is timely for the profession to take the lead in deciding what is scient
ifically appropriate to tell communities that may consider installing fluoridation equipment and holding fluoridation referendums in the late 1980s. 19
Gray cited the following figures to support his conclusion: “Survey results in British Columbia, with only 11 per cent of the population using fluoridated water, show lower average DMFT rates than provinces with 40–70 per cent of the population drinking fluoridated water. How does one explain this?. . . School districts recently reporting the highest caries-free rates were totally unfluoridated. ”20
NIDR 1986–1987
In 1986, the National Institute of Dental Research (NIDR) stepped in and organized—at great expense to the U. S. taxpayer—the largest survey of tooth decay ever undertaken in the United States. It examined the teeth of nearly forty thousand children in eighty-four communities. Findings were published in two papers, one by Yiamouyiannis21 and the other by Brunelle and Carlos. 22
Yiamouyiannis 1990
When Dr. John Yiamouyiannis (a well-known opponent of fluoridation and author of the book Fluoride: The Aging Factor23 ) obtained the raw data from this NIDR study, he found that there was no statistical difference in the DMFTs among children who had lived all their lives in a fluoridated community (F), children who had lived their whole lives in a non-fluoridated community (NF), and children who had lived their lives part of the time in a fluoridated community and part of the time in a non-fluoridated community (PF). In figure 8. 1, the three curves for DMFT across the age range from five to seventeen years are plotted for the F, NF, and PF children; the lines are essentially superimposed.
