(C) Peter Meiers - http://www.fluoride-history.de


Questionable Fluoride Safety Studies:

Bartlett vs. Cameron & Newburgh vs. Kingston


"The constant dosage of fluorine in water in these extremely attenuated concentrations may express itself in mild pathologic lesions of other tissues which, through their inherent vital functions, may be coincidentally repaired. No such function resides within the enamel, as is well understood by dental science. The disturbing influence of fluorine on the process of enamel calcification is never offset; hence, this lesion of the enamel remains as the only index of the toxicity of that element for the individual."

McKay, F.S.: J. Am. Dent. Assoc. 20 (1933) 1137-1149  


Somehow it was to be expected that mottling and staining of the teeth would not be the only toxic effect of fluoride, though this was apparently the only one within the scope of dentistry. After the examination, in February 1932, of a group of children in Minonk, Illinois, Henry Trendley Dean wrote in his report to the Surgeon General: "Following the Minonk examination, a new phase of this question seems ripe for further study. Is mottled enamel merely an oral manifestation of a general toxicity, or something similar? The hair of some of these mottled enamel cases is unusually coarse, almost like horse hair. Finger nails are apparently not normal. Two of the three local physicians state that there is apparently an unusually large amount of skin disorders among those using the city water supply. Future surveys will attempt to obtain this additional dermatological data in order to determine whether it correlates with the mottled enamel" (1). There was no follow-up, however.

Another opportunity to worry about possible fluoride effects on general health was associated with the mottled teeth survey in Texas. In this state there are many communities with up to 8 ppm fluoride in the tap water and, consequently, a high incidence of more severe cases of mottled teeth (2). Among the most afflicted communities were Post, Bartlett, Lubbock, Lamesa, Amarillo, Italy, Frost and Hereford. A pediatrician of Amarillo, Texas, reported in 1934 "defective development of the long bones in babies whose diet includes water with fluorides in toxic amount" (3). "Some of these babies have more tendency to bowing of the legs, even in the face of constant antirachitic therapy, thus supporting the theory that the toxic fluorides interfere with bone and dental metabolism" (3).  In 1936, the U.S. Public Health Service somehow felt a need to conduct a "chronic disease survey" in several Texas cities (4). In a letter to McKay Dean explained why Amarillo would be included: "Inasmuch as Wichita Falls (Texas) was one of the cities in the group, we thought it advisable to add Amarillo to the general survey and attempt to obtain information on an approximation of the incidence of mottled enamel in the population as a whole. Wichita Falls and Amarillo are about comparable in population. In the former the city water contains about 0.4 parts per million of "F"; in Amarillo the mean annual "F" content is close to 4.0 parts per million" (4a). But results of the survey were not published. In 1937, both communities were again surveyed, this time by dentists Trendley Dean, Frank Arnold, Walter Pelton, and Philip Jay, whose main interest was in the dental caries prevalence (5).  In a letter of Feb. 12, 1938, Dean told McKay: "We have just completed a study begun last October with respect to the relation of endemic fluorosis to dental caries. The study was made at Amarillo where the water contains approximately 4.0 p.p.m. and at Wichita Falls where the impounded surface supply contains about 0.4 p.p.m. of fluorine. The study was limited to 9-10-11-12-13 year old children. About five hundred children were examined at Amarillo; three hundred and fifty at Wichita Falls. Each child was examined independently by two dental officers after the facts with respect to continuity of residence and exposure had been verified by one or the other officer in a personal interview with each childīs parent. The analysis of these data have not as yet been completed. Clinical examinations were, of course, made by a dentist using a mirror and explorers" (5a). Again, the results were not published, even though they allegedly showed -according to Henry Klein, who was formerly with the USPHS- that native children of Amarillo had a lower caries incidence than children of Wichita Falls (6).

Since the late 1930´s a number of publications revealed pathologic fluoride effects other than mottled teeth, such as alterations of bone structure, thyroid gland enlargement, reduction of calcium content of blood as well as alterations in blood picture (7 - 10), the most detailed work being Kaj Roholm´s monograph "Fluorine Intoxication" (8) which Dean reviewed in 1938 (11). Inspired by such reports, and considering that contamination of food by fluoride is increasing because of widespread use of fruit and vegetable sprays containing sodium fluoride as the active agent and of phosphate fertilizer and stock food in which fluoride occurs as an impurity, researchers at the University of Chicago examined people in certain Illinois communities, i.e. Kempton and Bureau, where the water contained either between 1.2 - 3 (Kempton) or 2.5 ppm fluoride (Bureau) (12). They found no radiologically demonstrable sclerosis of the skeleton but suggested to continue the search for skeletal sclerosis in American communities where the fluoride content of drinking water exceeds 3 parts per million.

During a meeting of the Newburgh Fluoridation Study Committee, in April 1944, Trendley Dean questioned  the validity of the results of this study because there was no statement as to how long the corresponding water supplies had been in use. There could have been several changes in the water supplies for the study areas and "we really do not know what the exposure was previous to 20 years ago". Dean was of the opinion "that it was necessary to begin with a water supply of a specified number of years of continuous use, such as 30, 40 or 50 years, without any physical changes in the communal water supply involving the installment of new wells or the abandonment of old ones" (13).

Difficulties of getting persons with 20 years´ continual exposure make groups to be studied very small, Dean told the Committee on that very same meeting of April 1944 (13). He also gave details of still unpublished recent findings from examinations made by the USPHS at Bartlett, Texas, with 8 ppm fluoride in the water supply, Cameron, near Bartlett, with 0.4 ppm fluoride, and Britton, South Dakota, with about 7 ppm fluoride in the communal water supply:


"At 8.0 ppm F some bony changes were found although they did not result in functional impairment. These changes start in the lumbar region and the pelvis. Increased density was found in 13 of the 111 persons with over 20 years´ exposure that were found by house to house enumeration in a population of 1700 to 1800. No changes were found in the controls who were using a water supply with 0.4 ppm F. In those persons who had osteosclerosis hemoglobin values averaged 2 grams less per person than in those with no evidence of osteosclerosis. It appeared that if fluorine affects the hemoglobin it does so indirectly by producing accretional bony changes which encroach on bone marrow cavity rather than by direct toxic effect of the hemoglobin producing system.

No evidence of impaired hearing was reported.

There were indications of increased incidence of cataract among those 50 years of age or older in the fluoride areas. However, the data was not too good because of the small number of 50 or over in the controls. At 8.0 ppm F eight out of 49 individuals had cataract. In the controls one moderate cataract was found in 26 individuals. An additional community with 7.0 ppm F was checked and 18 cataracts found in a population of 59 individuals of requisite age and exposure. Out of a total control of 30 only one moderate cataract was found. ...

Another change was noted in the nails. From 10-20 percent of the younger individuals examined has a rather unusual type of nail structure, the most characteristic aspect being transverse white blotches often completely across the nail, usually symmetrical, and on all the nails, there very frequently being from three to five of these per nail. The incidence of these finally decreased with age, the oldest patient being 57. In the control area with 139 high school students examined, none showed transverse striations." (13)


This report nearly ended the Newburgh fluoridation "demonstration" even before it was begun, as Dean "could not agree that the proposed program could be considered a perfectly safe procedure from a public health point of view". David Bernard Ast, dental director of the New York State Health Department and dental consultant to the Childrenīs Bureau, was furious. "Territorial prerogative has always existed and continues to exist not only in the animal kingdom, but in the areas of scientific research as well. It is the kind of hide-and-seek play which frequently goes on among research people who have an overriding urge to be on record as the first to discover or the first to publish", he later described his thoughts about that situation in April 1944 (13a). Dean had told the committee at that meeting, that it would take at least a year or a year and a half to complete the USPHS toxicity studies, but already "in June 1944, without notifying New York State, Dean was in Michigan setting up the Grand Rapids study, to start as quickly as possible. The November 1944 issue of the Journal of the Michigan State Dental Society indicated that fluoridation was planned to start about December 1, 1944" (13a).

Despite Dean´s apparent "opposition", members of the Fluoridation Study group argued in support of the Newburgh - Kingston experiment. Thus, Edward Rogers, Assistant Commissioner, Medical Administration, said that "the proposed demonstration has had much publicity. The cities of Newburgh and Kingston are ready to give enthusiastic cooperation. The setup and authorizations are complete but to date no fluorine has been added. The project can be dropped with no more serious result than embarrasment to the Department. However, committees are getting ready to do this sort of thing and it is much better that it be done under controlled conditions. Cumulative effects, if any, will not appear for a number of years. If Dr. Dean´s studies produce evidence that the cumulative effects may be serious the demonstration can be discontinued. In the past the efficacy of new public health procedures has been difficult to measure because control periods were not set up clearly enough. With the exception of cataract the untoward effects presented here by Dr. Dean can be offset against the advantages which it is hoped will be obtained. Dr. Rogers also pointed out that further studies might not supply the necessary desired data, as to whether or not there may be any untoward effects." (13)

Samuel Levine, Pediatrician-in-Chief of the New York Hospital, suggested that "there were several alternatives that the Committee might take, one of which was to approve the project with certain clearly defined safeguards which could be outlined if the action was approved. The other was to postpone any action until more information is available. He was of the opinion that the advantages were far greater than the disadvantages and that a year might give no firmer basis for categorical decisions. He moved that the Committee approve the project with definite safeguards which will be outlined and presented to the Committee before final action. The motion was seconded by Dr. Gies." (13)

Philip Jay, of the University of Michigan, stated that "such an experiment was contemplated in Michigan but that it had been postponed until further study had been done there. However, he felt that this was the propitious time for such a study from a psychological standpoint and that the project could always be discontinued. He could foresee no serious consequences due to fluorination of water supplies in two years." (13)

Katherine Bain, of the Children´s Bureau, Maurice Pomeranz, a roentgenologist of the Hospital for Joint Diseases, and John Caffey, roentgenologist of the Babies´ Hospital of New York City, likewise approved the project. Pomeranz said that "a perceptible interval must elapse between the ingestion of the chemical and the appearance of the toxic effects. Most of the toxic effects are visible to the naked eye and that there would be adequate time to discontinue the whole proposal if necessary" (13). Caffey suggested "that Dr. Levine organize a pediatric group to determine what examinations should be made" (13). The chairman of the Committee, Harold Carpenter Hodge, chemist at the University of Rochester and toxicologist for the Manhattan Egineer District, was remarkably silent.

There was apparently no one to realize that the undesired effects reported were mostly on older people.

Of high importance, then, was the question of liability. David Bernard Ast replied that he "has a verbal opinion, shortly to be followed by a written one, from the Attorney General that there is no liability which may devolve upon the State in such a procedure as outlined. The municipality assumes no special liability or obligation other than that it must follow the directions specified by the State Department of Health in the study. It cannot be held liable unless it can be shown that through neglicence higher concentrations of fluorine have been added than have been specified" (13).

An appeasing letter from Dean´s boss, Rolla E. Dyer, Director of the National Institute of Health, reached the desk of New York State´s Health Commissioner Godfrey in November 1944. This letter referred to some Selective Service Data acquired by biochemist Frank James McClure, who claimed an equilibrium between fluoride content of water and  fluoride excretion in urine. Furthermore, three of five Colorado Springs physicians interviewed by Dean were of the opinion that there was nothing unusual in respect to the prevalence of cataracts in Colorado Springs (14). This did not really clarify some of the issues raised earlier.

The Newburgh-Kingston fluoridation experiment started in 1945. A preliminary report, presented on October 25, 1949, before the Dental Health Section of the American Public Health Association, "failed  to disclose any significant deviation in any of the factors studied" in response to the early unpublished study (16). However, just children had been examined in Newburgh,  there was no examination made on adults. In the meantime, certain agitators, especially in Wisconsin, undertook every effort to install fluoridation in as many cities as possible (17). At the 4th Annual Conference of the State Dental Directors, in 1951, Katherine Bain, a member of the Newburgh - Kingston Fluoridation Committee, announced: "the technical committee set up to work with that study set itself a goal which it wasn´t able to achieve. It had hoped to keep the study under wraps for ten years, and at the end of ten years come out with a definitive answer about what fluoride did, what its harmful effects might be. As you know, that study and other studies began having such results that people became interested, and the pressure was such that people felt we must go ahead with these programs" (18). How questionable the alleged favorable results in respect to caries incidence were, is another issue and will be discussed elsewhere.

In the "final report" on pediatric findings, presented in 1955 at the  New York Institute of Clinical Oral Pathology, certain changes were found (in children, as still no adults had been examined apparently) which were not considered significant, one related to hemoglobin: "Although there were a few more children in the range below 12.9 gm. per hundred milliliters in Newburgh, the mean for the two groups was closely alike." Concerning erythrocytes, the examiners found: "Similarly a slightly higher proportion of children in Newburgh were found to have a total erythrocyte count below 4,400,000 per milliliter, but the difference between the two groups as a whole was not significant. ... The findings on both the ophthalmological and otological examinations in the group of children selected fall well within the limits expected of any normal group of children of the age studied" (19). The higher incidence of "cortical bone defects", in 13.5% of the children  selected in Newburgh, compared to 7.5% of the children in Kingston, were considered to be "benign lesions of childhood" - and were never followed up.

In 1952, during Hearings before the House of Representatives the point was raised by Representative A. L. Miller of Nebraska, that there were still no studies on possible deleterious effects of fluoridation on pregnant woman, on old people, and on those with chronic diseases. Also, not one of the organizations, like the American Medical Association, the National Research Council, the American Public Health Association, and others which have testified to its safety had ever carried out any such experiments or examinations. "So why would they endorse it when there have been no experiments in that field? That is what bothers me" (21). Miller, a former public health officer in the state of Nebraska, had been an advocate of fluoridation and he had introduced the bill to fluoridate the water of Washington, DC. After learning, during the 1952 hearings, of the shortcomings of the first fluoridation studies, he apologized for having misled the appropriations committee to support his bill (21a)

Reviewing the 1952 Hearings, the American Dental Association was afraid the outcome could mean shortages in the funding of future fluoridation programs (21b):


"There will be no teeth in the report being prepared by the House Select Committee to investigate the Use of Chemicals in Foods and Cosmetics, of which Rep. James J. Delaney (D., N.Y.) is chairman. Even though legislation of some sort may be recommended, likelihood of its enactment is remote.

On the other hand, the report´s conclusions may influence the Public Health Service budget for the fiscal year beginning July 1, 1952. If the committee reports any adverse observations on fluoridation, it will decrease prospects on an allocation of funds to the states for technical assistance in fluoridation. Pointing up this possibility is the fact that Rep. E. H. Hedrick (D., W. Va.), a member of the Delaney Committee, is also a member of the powerful appropriations subcommittee that decides the size of the Public Health Service budget."


At the February 8, 1953, meeting of the American Association of Public Health Dentists, John Knutson reported House Resolution 2341 introduced by Representative Wier, Republican of Minnesota, to prohibit local tax supported water plants from fluoridating (21c). In order to "educate senators and congressmen" about fluoridation, letters were written by public health dentists to congressional delegations outlining the background and the history of fluoridation and pointing out the results obtained from fluoridation projects (21d). However, as the 83rd Congress was on its collective way home before the end of July, all bills of direct interest to dentistry were destined to lay over until 1954 (21e). Time enough for a study of the safety of fluoride for adults.

In September 1953, under the threat of another hearing being ahead, residents of Bartlett and Cameron again became victims of pseudo-medical interest, when Nicholas C. Leone and Eugene R. Zimmerman of the Public Health Service re-examined as many people as possible of the group examined ten years ago by another USPHS team, to make the whole fraud a "ten-year study" which would become subject to wide circulation (22-24). The result:


"When the data are reviewed critically, it is clear that the medical characteristics of the two groups, with the exception of dental fluorosis, do not differ more than would be expected of two comparable towns with or without an excess of fluoride in the water supply." (24) 


Which "data"? Useless tables giving numbers or percentages of a total number of people in each group that were classified as "abnormal" in various respects in 1943 and in 1953. Not how many of the "abnormal" findings were too high or too low, as compared to "normal". Not in what age group the abnormal findings were revealed, nor if several of the abnormal findings occurred in the same person, or after certain duration of exposure. No reader would be enabled to get at conclusions like "increased density was found in 13 of the 111 persons with over 20 years´ exposure" or "in those persons who had osteosclerosis hemoglobin values averaged 2 grams less per person than in those with no evidence of osteosclerosis". No statistical significance was found for the fact that by 1953 fourteen of the participants had died in Bartlett, yet only four in Cameron. The authors considered this higher mortality to be due to the fact that in Bartlett the participants were predominantly older. A reanalysis of the mortaility data by a committee of the American Medical Association (25) revealed:


"However, using Fisher´s exact method, we have calculated the probability that chance determined the difference between the age-adjusted deaths in the two sample populations. The result is in fact above the significant level (1 chance in 20) used by the authors for their criterion. These odds are approximately one in 21 that mere chance determined the difference (P=0.048)." 


Despite the obvious manipulations and the ludicrous inadequacy of the Bartlett-Cameron and the Newburgh-Kingston studies as a basis for assurance of fluoridation safety, these studies are still doggedly quoted to the public as evidence of "safety" for the ingestion of fluorides. Almost 50 years afterwards, dentists still look at them from their own narrow perspective, as the following quote from a discussion in a dental newsgroup (sci.med.dentistry) shows: "Waddaya say we eliminate all childhood immunizations until we get statistics up to your lofty standards?"




(1) H. T. Dean to Surgeon General, March 4, 1932, in the Ruth Roy Harris Papers, NLM; (2) Dean H. T., Dixon R. M., Cohen C.: "Mottled enamel in Texas", Publ. Health Rep. 50 (1935) 424; (3) Lemmon J. R., cf. Dean H. T. : "Chronic endemic dental fluorosis", J. Am. Med. Assoc. 107 (1936) 1269-1273, see also Ref. (2); (4) Memorandum H. T. Dean to Assistant Surgeon General L. R. Thompson, May 26, 1936, in the H. T. Dean papers, NLM; (4a) H.T. Dean to F.S. McKay, October 22, 1936, in the H. T. Dean papers, NLM;  (5) Amarillo Globe, Oct. 19, 1937, pp. 1-2; (5a) H.T. Dean to F. S. McKay, Feb. 12, 1938, in the H.T.Dean papers, NLM; (6) Klein H.: "Dental caries inhibition by fluorine - the historical perspective", J. Irish Dent. Assoc. 18:1 (1972) 9-21; (7) Speder & Charnot: "Syndromes osseux du type hyperparathyroidien et du type hypoparathyroidien, provoqués par l´intoxication par les divers sels de fluor et des intoxications minérales associées", La Presse Médicale No. 90 (Nov. 7, 1936) 1754; (8) Roholm K.: "Fluorine Intoxication", Kopenhagen - London 1937; (9) Wolff W. A., Kerr E. G.: "The composition of human bone in chronic fluorine poisoning", Am. J. Med. Sci. 195 (1938) 493; (10) Abbott G.: "Dangerous Water", Hygeia 17 (1939) 899, cf.  J. Am. Dent. Assoc. 27 (1940) 162; (11) Dean H. T.: "Fluorine Intoxication", Am. J. Publ. Health 28 (Aug. 1938) 1008-1009;  (12) Hodges P. C. et al.: "Skeletal sclerosis in chronic sodium fluoride poisoning", J. Am. Med. Assoc. 117 (Dec. 6, 1941) 1938; (13) Abstract of the proceedings of the meetings of the Technical Advisory Committee on the Fluoridation of Water Supplies with the Departmental Working Committee for the Newburgh - Kingston Demonstration, April 24, 1944; in the H. T. Dean papers, NLM; (13a) Ast D.B.: "Response to receiving the John W. Knutson Distiguished Service Award in Dental Public Health", J. Publ. Health Dent. 43:2 (1983) 101; (14) R. E. Dyer to E. S. Godfrey, Nov. 20, 1944, in the H. T. Dean papers, NLM; (15) "Dr. Godfrey retires as New York State Commissioner of Health", Am. J. Publ. Health 37 (1947) 951 (he was followed by Hilleboe); (16) Schlesinger E. R., Overton D. E., Chase H. C.: "Newburgh - Kingston Caries - Fluorine Study", Am. J. Publ. Health 40 (June 1950) 725; (17) McNeil D. R.: "The fight for fluoridation", Oxford 1957; (18) Proceedings of the Fourth Annual Conference of State Dental Directors with the Public Health Service and the Children´s Bureau, Washington D.C., June 6-8, 1951; in the Ruth Roy Harris papers, NLM; (19) Schlesinger E. R. et al.: "Newburgh - Kingston Caries - Fluorine Study. XIII. Pediatric findings after ten years", J. Am. Dent. Assoc. 52 (1956) 296; (20) "The Division of Dental Public Health, its authorization, functions, objectives, organization, resources, projects", prepared by the Division of Dental Public Health, Federal Security Agency, Public Health Service, 1950; in the Ruth Roy Harris papers, NLM; (21) A. L. Miller, in "Testimony of David B. Ast, representing the American Public Health Association", Hearings before the House Select Committee to investigate the use of chemicals in foods and cosmetics, House of Representatives, 82nd Congress, 2nd session, pursuant to H. Res. 74 and H. Res. 447, Washington 1952, p. 1759; (21a) Miller AL: District of Columbia Appropriations for 1953. Hearings before the subcommittee of the committee on appropriations. House of Representatives. 82nd congress. 2nd session, March 19, 1952, pp. 381-4;  (21b) "Washington News Letter", J. Am. Dent. Assoc. 44 (1952) 461; (21c) J. Publ. Health Dent. 13:1 (1953) 25; (21d) J. Publ. Health Dent. 13:2 (1953) 45; (21e) JADA 46 (1953) 697  (22) Leone N.C. et al.: "Medical aspects of excessive fluoride in a water supply. A ten-year study", p. 110, in .J. H. Shaw (ed.) "Fluoridation as a public health measure", AAAS, Washington 1954; (23) Leone N. C. et al.: "Medical aspects of excessive fluoride in a water supply", Publ. Health Rep. 69 (1954) 925; (24) Leone N. C. et al.: "Review of the Bartlett - Cameron Survey: a ten year fluoride study", J. Am. Dent. Assoc. 50 (March 1955) 277; (25) American Medical Association: Proceedings of the House of Delegates, Clinical session, Philadelphia, Pa., Dec. 3-5, 1957;