FAN Bulletin 2034

October 7, 2010

This is part 2 in our three part series giving the background to, and the details of, the Sept 17 public hearing on the preliminary report by the European Commission Scientific Committee on Health and Environmental Risks (SCHER, 2010).

Part 2. SCHER’s preliminary report of May 2010.

The report was mixed from the point of view of the fluoridation debate. On the one hand it indicated little scientific support for the notion that ingested fluoride reduced tooth decay.

On the other hand SCHER was somewhat dismissive about health effects of fluoride below 3 ppm (about the highest level found in Scandinavian countries). Reading between the lines one gets the feeling that the panel had no desire to see further fluoridation practiced in Europe, but had little inclination to either challenge the Irish and UK governments on this measure or to give any support to the notion that natural fluoride should be removed below 3 ppm.

Little evidence of benefit

The SCHER panel writes:

“There is a continuous controversy over the benefit of fluoride and, in particular, the practices of intentional water fluoridation in tooth decay prevention. This has led several countries to discontinue drinking water fluoridation and in some cases to expand it” (page 7).

“(T)he predominant beneficial cariostatic effects of fluoride in erupted teeth occur locally at the tooth surface” (page 26).

SCHER provides the figure used by Cheng et al. in the British Medical Journal (Cheng et al., 2007) that shows little difference in the decline in tooth decay in 12-year olds between fluoridated and non-fluoridated European countries. Referring to this figure the panel writes:

“independent of the fluoridation policies across European countries, there has been a consistent decline over time in tooth decay in 12 years old children from the mid-seventies, regardless of whether drinking water, milk or salt are fluoridated” (page 26).

SCHER cites Ismail and Hasson (2008) to support the claim that

‘the caries preventive effect of systemic fluoride treatment is rather poor” (page 27).

They also suggest other evidence that “water fluoridation plays a relatively minor role in the improved dental health” compared to other interventions (page 27).

SCHER cites just one recent study that implies some benefit to tooth decay reduction when comparing communities in Denmark at 0.125-0.25 ppm fluoride in water versus communities with less than 0.125 ppm (Kirkeskov et al., 2010). [However, these levels are so much lower than the levels recommended for water fluoridation in fluoridating countries one has to question the relevance to artificial water fluoridation. Moreover, at the September 17 SCHER hearing Rudolf Ziegelbecker Jr. offered some possible confounding factors that might have explained these differences at low fluoride concentrations, including delayed eruption of teeth, levels of other minerals in water - when fluoride is low so often are calcium and magnesium - and the levels of sunshine which is a factor in tooth decay because vitamin D production is a function of how much sunshine a child is exposed. PC].

SCHER also cites the York Review for some mixed evidence of a small benefit from water fluoridation (McDonagh et al., 2000) but point out that the studies were of “moderate quality” (page 28).

SCHER adds that

“A few water fluoridation discontinuation studies do not suggest significant increases in dental caries” and “the benefits of fluoridation to adult and elderly [populations in terms of reductions in coronal and root decay are limited (Seppa et al., 2000 a,b)” (page 28).

SCHER also cites the cross border studies from Ireland/Northern Ireland as indicating some benefit as well as studies by Truman et al. (2002) and Parnell et al. (2009). However, they do not cite the important study by Komarek et al. 2005, who found no benefit when they controlled for delayed eruption, which is seldom - if ever - done. Nor do they cite the study by Warren et al. (2009) that found no benefit when tooth decay was examined as a function of individual exposure to fluoride ingestion.

In their summary to the section on benefits SCHER confuses the issue somewhat by merging the benefits of water fluoridation and topical fluoride, when the panel writes:

“Water fluoridation as well as topical fluoride treatments (e.g. fluoridated toothpaste or varnish) appears to prevent caries, primarily on permanent dentition.” (page 29)

However, SCHER continues,

“No obvious advantage appears in favor of water fluoridation compared with topical prevention. The continued systemic exposure of fluoride from whatever source is questionable once the permanent teeth have erupted” (page 29).

Their overall conclusion is,

“SCHER agrees that topical application of fluoride is most effective in preventing tooth decay. Topical fluoride sustains the fluoride levels in the oral cavity and increased caries prevention, with reduced systemic availability. The efficacy of population-based policies, e.g. drinking water, milk or salt fluoridation, as regards the reduction of oral-health social disparities, remains insufficiently substantiated” (my emphasis, pc) (page 29).

In their summary statement SCHER states,

“Water fluoridation as well as topical fluoride treatments (e.g. fluoridated toothpaste or varnish) appears to prevent caries, primarily on permanent dentition, but topical application is the more efficient measure” (page 36).

SCHER adds

“In children a very narrow margin exists between achieving the maximal beneficial effects of fluoride in caries prevention and the adverse effects of dental fluorosis” (page 30).

All in all this is not a strong endorsement for water fluoridation.

SCHER on health effects of ingested fluoride

SCHER certainly puts most of our concerns on the table when they state at the outset of their preliminary report:

“A body of scientific literature seems to suggest that fluoride intake may be associated with a number of adverse health effects. Dental fluorosis and effects on bones (increased fragility and skeletal fluorosis) are two well documented adverse effects of fluoride intake. Systemic effects following prolonged and high exposure to fluoride have also been reported and more recently effects on the thyroid, developing brain and other tissues, and an association with certain types of osteosarcoma (bone cancer) have been reported.” (page 7)

However, the panel manages to discount nearly all of these effects based on claims of poor methodology, missing information or the doses not being relevant to water fluoridation or the natural levels in Europe.

Fluoride and the brain

I was disturbed by the way the panelists dismissed the Chinese studies (and two other studies) on IQ in one short paragraph, without even listing the bulk of the individual studies in either its references or bibliography.

I was particularly disturbed by the evolution of SCHER’s discussion on this matter.

After dismissing 19 Chinese studies, one Indian and one Iranian study, and criticizing the methodology of Tang et al.’s (2008) meta-analysis, they state in their conclusion to the neurotoxicity section:

“Available human studies do not allow concluding firmly that fluoride intake hampers children’s neurodevelopment” and “SCHER agrees that there is not enough evidence to conclude that fluoride in drinking water may impair IQ” [my emphasis]. (page 17)

But in their final conclusion, this becomes,

“Fluoride intake from drinking water does not hamper children’s neurodevelopment and impairs IQ at the level occurring in EU” (page 36).

Further research on key issues not worthwhile!

Worse still, when discussing further investigative work that may be necessary the SCHER panel states:

“Several adverse health effects have been postulated to be due to fluoride exposure, i.e. osteosarcoma, development neurotoxicity, and reproductive toxicity. However, most of the information is of limited quality and the observed effects mostly have been at high exposure levels not relevant for the European situation. Thus it is unlikely that additional research on potential adverse health effects will provide new data to support the risk assessment process.” page 30

In my view this is a cavalier statement for the following reasons:

1. Fluoride and osteosarcoma

Bassin et al. study (2006) on osteosarcoma found an effect at 1 ppm (i.e. not a high exposure). It has not been refuted, even though her thesis advisor claimed he would do so in May 2006 (Douglass et al, 2006). If Bassin is correct then young men may be dying because of fluoridation and yet according to SCHER they don’t need more data on this to “support a risk assessment process”!

2. Absence of study does not mean absence of harm

We have 23 studies all suggesting an association between lowered IQ in children and exposure to fluoride at levels estimated to be as low as 1.9 ppm (Xiang et al, 2003 a, b). Yet according to SCHER they don’t need more data to see if there is any association in fluoridated communities with lowered IQ (they didn’t even suggest examining IQ as a function of the severity of dental fluorosis). What kind of nonsense is this? If you don’t look you don’t find. The absence of study does not mean the absence of harm and the glaring fact is that apart from one small study in New Zealand (Morgan et al., 1998) not one single fluoridated country has attempted to investigate this matter with or without a “superior” methodology.

3. Studies should be refuted scientifically not rhetorically

It is beholden on SCHER or any other agency or entity that dismisses these many IQ studies from four different countries (with supportive findings from over 100 animal studies), all of which found an association, to recommend that fluoridated countries attempt to resolve this matter scientifically not rhetorically. If there were weaknesses in methodology then it is beholden on them to encourage those countries that practice fluoridation to do such studies and to recommend the kind of methodology that would satisfy. Ireland has had mandatory fluoridation since 1963 and has done no research on this matter or any other tissue except the teeth! I am sure their representatives at the SCHER meeting were delighted to read this message from SCHER.

Fluoride and endocrine disruption

Also disturbing was SCHER’s same citation of the ATSDR (2001) report used by the EFSA (2005) to the effect that fluoride was not an endocrine disruptor, when the later and more comprehensive report by the NRC (2006) indicated the very opposite - indeed the NRC dedicate a whole chapter to endocrine disruption. One wonders if the SCHER panel members had even read the 507-page report by the NRC, or if they had how closely they did so.

The end result of all this was the SCHER committee, like the EFSA (2005), was to focus most of their attention on fluoride’s effect on the teeth and the bone. There was little evidence that the SCHER panel pursued other health concerns with any more vigor than the EFSA. The result was the SCHER panel took the EFSA ULs at face value and then proceeded to show that they would not be exceeded in Europe.

Thus our task at the Sept 17 meeting in Brussels was to try to encourage the SCHER panel to do a better job of reviewing the current literature on fluoride’s effects on other tissues than the teeth and bone before the panel writes its final report.

FAN’s full criticisms of the SCHER preliminary report are contained in my submission to SCHER after the meeting, which I sent in on September 24 (Connett, 2010).

In part 3 in this series I will discuss the SCHER meeting held in Brussels on Sept 17.

Paul Connett

References:

ATSDR (Agency for Toxic Substances and Disease Registry). 2001. Toxicological profile for fluorides, hydrogen fluoride, and fluorine. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
NOTE: SCHER cites the 2001 draft report, at http://www.fluoridealert.org/pesticides/atsdr.fluor.toxprofile.2001.pdf
The final ATSDR report in 2003 is at http://fluoridealert.org/re/atsdr.final.toxprofile.2003.pdf
Both have the same language that fluoride is not an endocrine disruptor.

Bassin EB, Wypij D, Davis RB, Mittleman MA. 2006. Age-specific fluoride exposure in drinking water and osteosarcoma (United States). Cancer Causes and Control 17(4):421-8. May.

Cheng KK, et al. 2007. Adding fluoride to water supplies. BMJ 335(7622):699-702. October 6.

Connett P. 2010. Critique of SCHER report, “Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water, 18 May 2010.” September 24.
http://fluoridealert.org/re/connett.sept.24.2010.pdf

Douglass CW and Joshipura K. 2006. Caution needed in fluoride and osteosarcoma study. Cancer Causes and Control 17(4):481-2. May.

EFSA (European Food Safety Authority). 2005.Opinion of the Scientific Panel on Dietetic Products, Nutrition and Allergies on a request from the Commission related to the Tolerable Upper Intake Level of Fluoride. Request N° EFSA-Q-2003-018). Adopted on 22 February 2005.

http://fluoridealert.org/eu.tolerable.upper.intake.2005.pdf

Ismail AI and Hasson H. 2008. Fluoride supplements, dental caries and fluorosis: a systematic review. J Am Dent Assoc. 139(11):1457-68.

Kirkeskov L et al. 2010. The association between fluoride in drinking water and dental caries in Danish children: Linking data from health registers, environmental
registers and administrative registers. Community Dentistry Oral Epi. (in press)

Komárek A, Lesaffre E, Härkänen T, Declerck D, Virtanen JI. 2005. A Bayesian analysis of multivariate doubly-interval-censored dental data. Biostatistics 6(1):45-55.

McDonagh M, et al.2000. A systematic review of public water fluoridation. NHS Center for Reviews and Dissemination. University of York, September 2000.
http://www.bmj.com/cgi/content/full/321/7265/855

Morgan L, et al. 1998. Investigation of the possible associations between fluorosis, fluoride exposure, and childhood behavior problems. Pediatr Dent 20: 244-52.

NRC (National Research Council of the National Academies. 2006. Fluoride in drinking water: a scientific review of EPA’s standards. Washington D.C.: National Academies Press. http://www.nap.edu/catalog.php?record_id=11571

Parnell C, Whelton H, O’Mullane D. 2009. Water fluoridation. Eur Arch Paediatr Dent. 10:141-8.

SCHER (Scientific Committee on Health and Environmental Risk). 2010. Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water. European Commission. Directorate-General for Health & Consumers. May 18.
http://fluoridealert.org/scher.fluoride.may.2010-2.pdf

Seppa, L, Karkkainen, S Hausen H. 2000a. Caries trends 1992-1998 in two low-fluoride Finnish towns formerly with and without fluoridation. Caries research 34(6):462-8.

Seppa, L, Karkkainen, S Hausen H. 2000b. Caries in the primary dentition, after discontinuation of water fluoridation, among children receiving comprehensive dental care. Community dentistry and oral epidemiology 28(4):281-8.

Tang QQ, et al. 2008. Fluoride and Children’s Intelligence: A Meta-analysis. Biol Trace Elem Res. 126:115-20.

Truman, BI, et al. 2002. Reviews of evidence on interventions to prevent dental caries, oral and pharyngeal cancers, and sports-related craniofacial injuries. American journal of preventive medicine 23(1 Suppl):21-54.

Warren JJ. et al. 2009. Considerations on Optimal Fluoride Intake Using Dental Fluorosis and Dental Caries Outcomes - A longitudinal Study. Journal of Public Health Dentistry 69(2):111-5

Xiang Q, et al. 2003a. Effect of fluoride in drinking water on children’s intelligence. Fluoride 36(2):84-94.
http://fluoridealert.org/scher/xiang-2003a.pdf
Xiang Q, et al. 2003b. Blood lead of children in Wamiao-Xinhuai intelligence study. Fluoride 36(3):198-9.
http://fluoridealert.org/scher/xiang-2003b.pdf

Ziegelbecker Jr. R. 2010. Systemic fluoridation and important confounders. A schematic version of Rudolph Ziegelbecker’s presentation to the European Committee SCHER committee at the September 17 meeting on fluoride in Brussels.
http://fluoridealert.org/re/ziegelbecker.sept.2010.pdf