1997, pp 195-204
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FLUORIDE 30 (3) 1997, pp 195-204 |
International Society for Fluoride Research | Table of Contents |
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DISCUSSION - News and Views 195
We begin this section with an abstract of the Washington Post article of Monday, June 16, 1997, referred to by Professor Miller in his Editorial.
POISON PASTE
Warning Labels Will Make You Brush With Care
Don Oldenburg
The author, a Washington Post Staff Writer, reports on the new warning labels required by the Food and Drug Administration on all fluoride toothpastes and dental care products shipped as of April 7. The warnings include one that reads:
"If you accidentally swallow more than used for brushing, seek professional help or contact a poison control center immediately."
The article points out that none of the caveats that began appearing on toothpaste tubes in 1991 had so candidly broached the risks of ingesting too much fluoride. The general warnings on toothpaste products that displayed the American Dental Association seal of approval had heretofore cautioned: "Don't Swallow -- Use only a pea-sized amount for children under six," and "Children under 6 should be supervised while brushing with any toothpaste to prevent swallowing." The word "poison" had not been used.
A director of research and development at the laboratories of one of the toothpaste makers is quoted, commenting on containers of the chemical:
"When I receive the fluoride here, it has a skull-and-bones on it ... If a child was to take a big spoonful of this fluoride, I don’t think he could swallow it, but if he did get it down, it is a poison and the child could die. If a child ingested a whole tube of toothpaste, he should be taken right to the emergency room and he would either get his stomach pumped or get some kind of antidote."
She listed three ingredients found in most toothpastes which pose health risks if too much is ingested: sorbitol, a liquid that keeps toothpaste from drying out, is a laxative that could cause diarrhea in children; sodium lauryl sulfate, an ingredient that makes toothpaste foam, can also be a diarrheic; but the fluoride poses the most danger if too much toothpaste is swallowed -- particularly to younger children.
"Small amounts of this material go a long way in causing disruption in their bodies because they are so small. The fluoride in toothpaste is considered a drug. Even though it is an over-the-counter drug, we are altering the body when we brush our teeth with a fluoride toothpaste or tooth gel. ... As normal consumers, you’re not aware of these things. But I’m sure our 800 number is going to get more calls as products with the new warnings show up on store shelves."
The article suggests that this summer, as toothpaste shipments with the new labeling replace older inventories, consumers will see nearly twice the warnings displayed on the back of tubes and cartons -- the ADA’s general warnings along with the new FDA-required statement that starts with: "Keep out of the reach of children under 6 years of age."
Commenting on research which has shown that, because they are not yet in control of their swallowing reflex, children 4 to 6 years old typically swallow toothpaste when brushing, the director stated: "That’s why it’s recommended that kids get only a pea-size amount of toothpaste, because most of that goes down their throats." A 1995 study at the Medical College of Georgia School of Dentistry had found that about half the children this age do not spit out or rinse out -- they swallow the toothpaste instead. Making matters worse, they tend to use too much toothpaste on their own -- especially when they use flavored children’s toothpastes.
While agreeing that the cavity-preventing effectiveness of fluoride has been demonstrated, the article notes that too much fluoride not only can be dangerous, but can also cause dental fluorosis that discolors or spots developing teeth. Research conducted by the School of Dental Medicine at the University of Connecticut Health Center had concluded that brushing with more than a pea-size amount of toothpaste more than once daily contributed to most of the fluorosis cases it observed in young children. In areas where the drinking water contains fluoride, children who swallow even the pea-size amount of toothpaste are getting too much fluoride and are at risk for fluorosis.
The vice president of "corporate communication and market development" of a small company which in 1975 introduced the first "natural" toothpaste on the market, is quoted: "I haven’t heard of problems beyond fluorosis, but that’s a valid concern. There are some kids getting too much fluoride ... " Besides its "natural" toothpastes that contain fluoride, the company makes a nonfluoride toothpaste in flavors including "cinnamint" and "fennel." When it recently began marketing its new line of natural toothpaste for children, it left out the synthetic sweeteners, neon colors and bubble gum flavors. But the toothpastes, called Silly Strawberry and Outrageous Orange, contain the same levels of fluoride as competitors’ toothpastes. It was explained: "It is always kind of a trade-off. We made a decision to have only fluoride toothpaste for children because that has been proven to be the overall benefit of toothpaste for children. We feel the benefit outweighs the negative ... You have to get the education across to your kids that you don’t suck the toothpaste down, just as you have to work with your kids to brush their teeth. The alternative is they don’t brush. I guess we don’t feel like the risk factor is that high to make that trade-off."
The article reports that many in the toothpaste industry feel the new FDA warnings may be overstating the risks. An ADA spokesman is quoted: "Our position was that they went a little too far. There wasn’t really a need for the cautionary statement about the danger of poisoning if you’ve ingested too much. If children were to sit around the bathroom eating toothpaste, which younger children could do, there is not enough fluoride in the toothpaste to cause them any acute harm. That just doesn’t happen ... If you tried to eat a lot of toothpaste, you’d throw it up." He conceded that poison control centers do receive reports of fluoride poisonings every year, but said that the ADA is not aware of any of those cases resulting in adverse effects. "It just hasn’t proven to be that kind of a problem .... We didn’t think you needed a label like that because it could unnecessarily scare consumers into not using toothpaste."
DISCUSSION - Letter to Editor 197
CRITIQUE OF STUDY
(Guha-Chowdhury N, Drummond BK, Smillie AC. Total fluoride intake in children aged 3 to 4 years. A longitudinal study. Journal of Dental Research. 75 (7) 1451-1457 1996)
An abstract of a New Zealand study of fluoride intake by 3-4 yr old children, by N Guha-Chowdhury and collaborators, was printed in the May 1997 issue of Fluoride (pages 126-127). The full study describes how duplicate portions of all food and drink consumed over 24 hours by 66 children resident in fluoridated (n = 32) and low fluoride (n = 34) areas of New Zealand were collected on three separate days over a period of 12 months and analysed for fluoride. Fluoride intake from ingestion of toothpaste was also determined for each child. It was concluded that fluoride from diet alone did not exceed 0.04 mg/kg of body weight (0.74 mg/day) and from diet plus toothpaste did not exceed 0.07 mg/kg of body weight (1.31 mg/day). Children from low fluoride areas taking currently available dosage of supplements would exceed the intake in fluoridated areas. The results suggested that the recommended fluoride tablet dosage needs to be further reduced if dental fluorosis is to be avoided.
The full study has two tables of information. Table 1 shows mean and standard deviation of the fluoride intakes, in mg/day and mg/kg body weight, for diet alone and diet plus toothpaste for each of the three collections in fluoridated and low fluoride areas. Table 2 shows range, mean, standard deviation and 95% confidence interval for the combined data of the three collections for diet alone and diet + toothpaste, in mg/day and mg/kg body weight, for fluoridated and low fluoride areas. It also includes the range for fluoride intake in low fluoride areas after adding fluoride values of tablets at four dosage levels (1 mg, 0.5 mg, 0.25 mg and 0.1 mg) to the diet plus toothpaste range.
I make the following observations:-
1. It was stated that the combined mean fluoride intakes exceeded the diet only fluoride intakes in low fluoride and fluoridated areas by approximately 70% and 50% respectively. The true values are approximately 226% and 89% respectively.
| Diet Alone | Diet and Toothpaste | |||||
| Baseline | 6 months | 12 months | Baseline | 6 months | 12 months | |
| 1st value=mg/day 2nd=mg/kg bw | 1st value=mg/day 2nd=mg/kg bw | |||||
| Low-fluoride areas (n=34) |
0.14 ± 0.08 0.008 ± 0.005 |
0.15 ± 0.10 0.008 ± 0.005 |
0.15 ± 0.09 0.008 ± 0.005 |
0.56 ± 0.33 0.032 ± 0.018 |
0.53 ± 0.32 0.028 ± 0.016 |
0.39 ± 0.26a 0.019 ± 0.012a |
| Fluoridated areas (n=32) |
0.34 ± 0.22 0.019 ± 0.013 |
0.31 ± 0.16 0.016 ± 0.008 |
0.44 ± 0.30 0.022 ± 0.015 |
0.69 ± 0.37 0.040 ± 0.024 |
0.70 ± 0.37 0.037 ± 0.020 |
0.64 ± 0.32 0.032 ± 0.017 |
| aSignificant (p < 0.05) reduction in fluoride intake over time. | ||||||
| Low-fluoride areas | Fluoridated areas | |||||
| Range | Mean | 95% CI | Range | Mean | 95% CI | |
| 1st value=mg/day 2nd=mg/kg bw | 1st value=mg/day 2nd=mg/kg bw | |||||
| Diet Alone |
0.05-0.31 0.004-0.02 |
0.15± 0.06 0.008 ± 0.003 |
0.13-0.17 0.006-0.010 |
0.09-0.74 0.004-0.04 |
0.36 ± 0.17 0.019 ± 0.009 |
0.30-0.42 0.015-0.023 |
| Diet + Toothpaste |
0.17-1.21a 0.01-0.06 |
0.49 ± 0.25 0.027 ± 0.012 |
0.41-0.57 0.023-0.031 |
0.26-1.31 0.01-0.07 |
0.68 ± 0.27 0.036 ± 0.015 |
0.59-0.77 0.030-0.042 |
| (Diet+Toothpaste)a + Fluoride Tablets |
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a + 1.00 mg/day 1.17-2.21 a + 0.50 mg/day 0.67-1.71 a + 0.25 mg/day 0.42-1.46 a + 0.10 mg/day 0.27-1.31 |
| a Range (0.17-1.21 mg/day) of fluoride intake from diet and toothpastes found in the low-fluoride areas |
2. The range of fluoride ingested from toothpaste alone is given as 0 -1.29 mg/day. In Table 2, the largest value for fluoride from diet + toothpaste is 1.31 mg/day in fluoridated areas, which leaves 0.02 mg/day for diet only. The smallest value, quoted in those areas for diet alone, is 0.09 mg/day, which leaves a discrepancy of 0.07 mg/day. Assuming the other fluoride values are correct, the maximum fluoride value from diet + toothpaste is at least 1.38 mg/day.
3. The maximum fluoride intake from diet + toothpaste DID exceed 0.07 mg/kg body weight (1.31 mg/day) in fluoridated areas, unless the previously described discrepancy can be explained away. The abstract states that fluoride supplement data were determined for each child. These data are not included in any of the total fluoride intakes. The Table 2 values of total fluoride intake for low fluoride areas, assuming four possible fluoride tablet values (1 mg, 0.5 mg, 0.25 mg and 0.1 mg), indicates that the true maximum intake was possibly as high as 2.21 mg (recommended fluoride supplement dosage in New Zealand low fluoride areas is 1.0 mg/day).
4. True random samples of the population of 3- 4 year old children were not possible, because of the exclusion of children with one or two carious lesions. Hence the statistics quoted in the abstract were misleading, because these selection criteria were not given in the abstract.
5. The authors acknowledge that the sample sizes are small.
This study appears to be another small sample size selective study trying to shore up the crumbling fluoride edifice. It attempted and failed to show that fluoride intake was within the 50 year old determined "optimal range". It is today generally accepted that the cariostatic effect of fluoride is predominantly topical and that fluoride tablets should not be given to young children. Toothpaste alone may well be sufficient to minimise caries, if the dubious benefits of fluoride are to be believed. It probably would reduce dental fluorosis, which is certainly not considered a cosmetic defect by affected people -- ask any young woman with discoloured fluorosed teeth. Now seems to be the time to stop water fluoridation and feeding supplements to unsuspecting children. The last sentence of the study begins - "Even if fluoride use were to become totally topical ...". Are the authors feeling their way to a solution to the fluoride question?
Bill Wilson
118 Forrest Hill Road
North Shore City, New Zealand
The following letter is in response to the critique by Professor Albert Schatz in Fluoride 30 (2) 1997 page 131-133. The discussion continues on following pages.
NO ASSOCIATION BETWEEN FLUORIDATION OF WATER AND SIDS
Our ecological study showed there was no linear association between median fluoridation and SIDS mortality rates in New Zealand.1 Similarly the quadratic curve drawn on our figure is not statistically significant, thus there is no evidence for a paradoxical effect.
We have examined water fluoridation in the New Zealand Cot Death Study,2,3 a large nationwide case-control study (379 cases and 1551 controls). 59.9% of SIDS cases occurred in households where the water was fluoridated compared with 61.0% of controls who lived in fluoridated areas (OR= 0.96; 95% confidence interval 0.76, 1.20; not significant). After adjustment for a wide range of potential confounders (n=25; sociodemographic, pregnancy related, infant related and infant care practices, which includes type of infant feeding), fluoridation was not associated with SIDS (Dick et al, unpublished data).
We can be confident that water fluoridation does not cause SIDS.
E A Mitchell, Associate Professor in Paediatrics, University of Auckland
J M D Thompson, Biostatistician, Paediatrics, University of Auckland
B Borman, Epidemiologist, Regional Health Authority, Wellington
R P K Ford, Community paediatrician, Healthlink South
E A Dick, Canterbury Cot Death Fellow, Healthlink South
References
200 Letter to Editor
FLUORIDATION AND INFANT DEATHS
Proponents of fluoridation have yet to provide convincing evidence that it is safe. Until they do that, they are using humans as guinea pigs.1 It is imperative that the safety of a highly toxic substance such as fluoride be unequivocally established. The responsibility to do that rests squarely on those who allege that fluoridation is safe. The fact that low levels of fluoride exhibit paradoxical effects (as low-level radiation and low levels of many chemical compounds do)2 makes it difficult to provide convincing evidence that fluoridation is safe. lf the safety of fluoridation cannot be unequivocally established, it should be discontinued. Dental caries is not a life-threatening problem which justifies the use of a highly toxic substance.
One cannot adequately evaluate the role of fluoride in Sudden Infant Death Syndrome (SIDS) without studying significant numbers of malnourished infants because they are most susceptible to fluoride toxicity.3 Until such well-designed research is conducted, one cannot conclude that fluoride is not involved in SIDS. The toxic effect of fluoride in Chilean children was clearly revealed because most children in that country were malnourished.3 Because fluoride was toxic to malnourished Chilean children, it is toxic to malnourished children everywhere, and especially toxic to malnourished infants.
Those who allege that fluoride is not involved in SIDS do not know the total daily intake of fluoride of malnourished infants, whether they are breast fed or not. For some of them, the total daily intake of fluoride may be significantly higher than the total amount of fluoride which they ingest from drinking water.2 'Those who disregard any important variable "cannot exclude the explanation [they] have not considered." 4
Albert Schatz PhD
Professor Emeritus, Temple University
6907 Sherman Street, Philadelphia
Pennsylvania 19119, USA
References
MITCHELL REJOINDER
Less than 20% of sudden infant death syndrome (SIDS) cases occur in infants with low birthweight (LBW, < 2500 g).1 In 1987-1990 we undertook a large case-control study. The methods have been described in detail,1,2 but in brief, the cases (n=485) were all SIDS deaths in the study regions. The controls (n=1800) were randomly selected from all live births and representative of all births in the study regions. They were not matched by region, hospital of birth, ethnicity or date of birth. We found that 59.9% of SIDS cases occurred in households where the water was fluoridated compared with 61.0% of controls who lived in fluoridated areas. This study included 82 cases and 84 controls of LBW. We adjusted for a wide range of potential confounders including birthweight, and fluoridation was not associated with SIDS, even in infants with LBW.
Professor Schatz’s study tells us nothing about SIDS as it relates to infant mortality in a developing country in the 1950s with extraordinary high infant mortality rates (>100/1000 live births). SIDS mortality rates are <2/1000 live births. Deaths from infections continue to be the major cause of death in infancy in the developing world, and SIDS is relatively rare.
Poisoning has frequently been postulated as the cause of SIDS. The poisons implicated include therapeutic drugs, ammonia, water fluoridation, nappy sterilisers, immunisations and more recently poisonous gases from cot mattresses. It is appropriate to take these claims seriously and fully investigate them. We have undertaken an ecological study 3 and a large case-control study and have found no association between fluoridation and SIDS. Continuing to proclaim a causal link causes unnecessary distress to families whose baby has died and diverts attention away from the successful SIDS education campaign which has halved SIDS mortality in many countries throughout the world.4
E A Mitchell
References
SCHATZ REJOINDER
Mitchell et al have not ruled out an association of fluoride and SIDS. They consider only the fluoride content of drinking water, but present no information about the total fluoride ingested by each victim of SIDS. They have therefore disregarded the most basic tenet in forensic toxicology. For example, if the suspected cause of death is an overdose of sleeping pills, it is necessary for the coroner to know the amount of the medication in the body of the particular victim. The amount of medication in each pill in the original bottle of pills does not provide the necessary information. Nor does the number of pills missing from the bottle.
The concentration of fluoride in drinking water may vary significantly from day to day. Even if that concentration were constant, the daily consumption of water varies for different individuals. The ingestion of fluoride from other sources also varies for different individuals. As in forensic medicine, it is necessary to determine the amounts of fluoride in the bodies of SIDS victims. Statistical analysis is no substitute for that quantitative information.
Decades ago Fred Exner MD opposed fluoridation because he said its proponents were, in effect, telling people: "Drink as much water as you want. You’ll get the right dose of fluoride with no harmful effects." Exner compared that to a doctor who prescribes a potentially toxic medication and tells the patient: "Take a pill whenever you want, and you’ll get the right dose with no harmful effects." If pediatricians prescribed medication for children that way, they would be guilty of malpractice.
Albert Schatz
FINAL WORDS (Each was invited to submit a final summing up)
Mitchell et al reported that non-breast feeding significantly increased the risk of SIDS. It is known that an infant formula made with fluoridated water increases an infant’s fluoride intake by up to 200 times that of intake from the mother’s breast, which supplies milk mostly free of fluoride. Mitchell et al provide no data on the ingestion of fluoride from this source of intake, nor include it as a possible risk. It is nonsensical to suppose that every infant will ingest the "mean fluoride intake" of an area. Without recording individual fluoride intakes, and with small samples like 82 cases and 84 controls, it is not possible to rule out a contributing role of fluoride. Also not considered were individual variations in susceptibility to fluoride toxicity. Nonetheless, as was pointed out in my critique, their results are compatible with a paradoxical effect from low doses.
In their study which I criticized they emotively referred to "unethical scare tactics" of opponents of fluoridation. I repeat that proponents of fluoridation have not provided convincing evidence that it is safe. Opponents should not have to provide "conclusive proof" of harm. Many well-documented reports of harm caused by fluoride make the practice of fluoridation unethical.
Albert Schatz
As 90% of SIDS occur before 6 months of age, almost all the SIDS infants’ fluoride intake comes from breastmilk or infant formula. The mean fluoride intakes from food and drinks in fluoridated and nonfluoridated areas in New Zealand were 0.263 and 0.082 mg F/day respectively.1 If fluoridation caused SIDS we would have expected to have seen a higher SIDS rate in fluoridated areas. This was not seen.
Other sources of fluoride need to be considered, especially fluoride tablets and toothpaste. Only one (0.25%) SIDS parent mentioned "possibly half a fluoride tablet". As the first teeth erupt at approximately 6-7 months, toothpaste is not an important source.
Our study clearly shows there is no indication of a relationship between fluoridation of the water supply and SIDS in New Zealand and also that there is no evidence of a paradoxical effect.
E A Mitchell
Reference
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FLUORIDE 30 (3) 1997, pp 195-204 |
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