Why We Have Not Changed Our Minds about the Safety and Efficacy of Water Fluoridation

WHY WE HAVE NOT CHANGED OUR MINDS ABOUT THE SAFETY AND EFFICACY OF WATER FLUORIDATION ERNEST NEWBRUN and HERSCHEL HOROWITZ* Introduction Perspectives in Biology and Medicine recently published an opinion piece by John Colquhoun, ''Why I changed my mind about water fluoridation''[I]. The stated purpose of Perspectives in Biology and Medicine is to convey new ideas or stimulate original thought in biological and medical sciences. However , new data are not presented in Colquhoun's paper; rather, the paper repeats earlier criticisms of water fluoridation, using selective and highly biased citations of the scientific and nonscientific literature [2-10]. Colquhoun served as the Principal Dental Officer ofthe city ofAuckland, New Zealand, during which time he accepted the findings that water fluoridation is effective in reducing caries. He writes that he became troubled by the declining caries prevalence in nonfluoridated areas as well as in fluoridated areas. Then in 1984 and 1985 he published his own evaluation of records collected from children in Auckland, which is fluoridated, and neighboring Onehunga, which is not fluoridated, and reported that the dental health in Auckland was only "slightly better" than in Onehunga. All ofthis led him to question the efficacy ofwater fluoridation. Colquhoun is similar to several other opponents ofwater fluoridation who have stated that they once supported this public health measure [11, 12]. However, it is important to recognize that simply by claiming to be a former advocate and now being strongly opposed to fluoridation in no way validates one's judgment nor excuses distortion of the literature [13]. Colquhoun now is a well-known opponent of communal water fluoridation who criticizes studies that support fluoridation for poor design (e.g., non-blind examination, nonrandom selection of subjects) and ignores gross defects in the methods used in studies that find no caries reduction in fluoridated communities. He is the editor of Fluoride, a magazine pub- *Department of Stomatology, University of California, San Francisco, CA 94143.© 1999 by The University of Chicago. All rights reserved. 0031-5982/99/4303-1 109$01.00 526 Ernest Newbrun and Herschel Horowitz ¦ Water Fluoridation lished by the International Society for Fluoride Research, of which he is also the treasurer. Despite its propitious title, Fluoride is primarily a vehicle for printing articles that decry the benefits of communal water fluoridation (13 of Colquhoun's 73 citations are from this anti-fluoride publication). Colquhoun's paper is in the same genre. In it, Colquhoun states that water fluoridation is ineffective in reducing caries and that the decline in caries observed in most Western industrialized countries is not due to fluorides but rather to a vaguely described "improved nutrition." He also contends that water fluoridation is harmful to teeth (causes fluorosis) and to general health (causes bone cancer, weakens bones, affects behavior) and lacks universal endorsement. In general, Colquhoun ignores the overwhelming findings of the efficacy of water fluoridation in reducing caries prevalence, not only by failing to cite recent individual studies from various parts of the world—including Australia, Britain, Canada, Ireland, and New Zealand, as well as the United States—that have reached this conclusion, but also by omitting major reviews that have cited these studies [14, 15]. Instead, Colquhoun primarily cites his own and Diesendorf's publications, which contain significant errors, misquotations, and the use of questionable data [16]. Other reports that Colquhoun cites that supposedly do not show benefits of fluoridation failed to establish residence histories of the sample population, used crude measurements of caries prevalence, and were based on intake of natural fluoride, the level of which is neither controlled nor monitored [17, 18]. Claims that fluoride is harmful have been amply reviewed by international , national, state, and local authorities, as summarized in Table 1 [1932 ] . The committees or commissions that wrote these reports included independent eminent experts in a variety of different fields—such as medicine , epidemiology, pathology, pharmacology, and toxicology—as well as scientists and water engineers. The conclusions have been remarkably similar : namely, that the benefits ofwater fluoridation far outweigh any potential health risks. Consumer Reports magazine has aptly summarized the situation : "The simple truth is that there is no 'scientific controversy' over the safety of fluoridation. The practice is safe, economical...