| 2001 |
Whiting P, McDonagh M, Kleijnen J |
Association of Down's syndrome and water fluoride level: a systematic review of the evidence |
BMC Public Health 2001 1: 6 |
waterfluoride |
Background A review of the safety and efficacy of drinking water fluoridation was commissioned by the UK Department of Health to investigate whether the evidence supported a beneficial effect of water fluoridation and whether there was any evidence of adverse effects. Down's syndrome was one of the adverse effects reported. The aim of this review is to examine the evidence for an association between water fluoride level and Down's syndrome. Methods A systematic review of research. Studies were identified through a comprehensive literature search, scanning citations and online requests for papers. Studies in all languages which investigated the incidence of Down's syndrome in areas with different levels of fluoride in their water supplies were included. Study inclusion and quality was assessed independently by 2 reviewers. A qualitative analysis was conducted. Results Six studies were included. All were ecological in design and scored poorly on the validity assessment. The estimates of the crude relative risk ranged from 0.84 to 3.0. Four studies showed no significant associations between the incidence of Down's syndrome and water fluoride level and two studies by the same author found a significant (p < 0.05) positive association (increased Down's syndrome incidence with increased water fluoride level). Only two of the studies controlled for confounding factors and only one of these presented summary outcome measures. Conclusions The evidence of an association between water fluoride level and Down's syndrome incidence is inconclusive. |
- |
BMC |
| 2001 |
Demos LL, Kazda H, Cicuttini FM, Sinclair MI, Fairley CK |
Water fluoridation, osteoporosis, fractures--recent developments. |
Aust Dent J 2001; 46(2): 80-7 |
waterfluoride |
BACKGROUND: Optimal (1ppm) water fluoridation is seen as the most socially equitable way to prevent dental caries, however concerns about the safety of fluoridation are periodically raised. METHODS: Research on effects on bone published since the 1991 National Health and Medical Research Council report on water fluoridation was reviewed. RESULTS: Thirty-three studies were identified. Adverse effects in animal feeding studies were only seen at doses much greater than those currently used in artificial water fluoridation. The majority of animal studies showed no effect or a beneficial effect of low fluoride doses. The results of ecological studies were conflicting. One of the two cohort studies showed an increase in fracture incidence at fluoride levels four times greater than optimal water fluoridation and the other showed no effect after 20 years' optimal fluoridation. The cross-sectional studies showed a favourable effect on bone mineral density. The clinical trials predominantly showed increased bone density in several sites associated with fluoride treatment of 9-22.6mg fluoride per day for one-four years. CONCLUSION: These studies provide a substantial body of evidence that fluoride at up to 1ppm does not have an adverse effect on bone strength, bone mineral density or fracture incidence. |
Medline |
|
| 2000 |
McDonagh MS, Whiting PF, Wilson PM, Sutton AJ, Chestnutt I, Cooper J, Misso K, Bradley M, Treasure E, Kleijnen J |
Systematic review of water fluoridation. |
BMJ 321(7265): 855-9, 2000 7 NHS CRD Report 18, 2000 |
waterfluoride |
OBJECTIVE: To review the safety and efficacy of fluoridation of drinking water. DESIGN: Search of 25 electronic databases and world wide web. Relevant journals hand searched; further information requested from authors. Inclusion criteria were a predefined hierarchy of evidence and objectives. Study validity was assessed with checklists. Two reviewers independently screened sources, extracted data, and assessed validity. MAIN OUTCOME MEASURES: Decayed, missing, and filled primary/permanent teeth. Proportion of children without caries. Measure of effect was the difference in change in prevalence of caries from baseline to final examination in fluoridated compared with control areas. For potential adverse effects, all outcomes reported were used. RESULTS: 214 studies were included. The quality of studies was low to moderate. Water fluoridation was associated with an increased proportion of children without caries and a reduction in the number of teeth affected by caries. The range (median) of mean differences in the proportion of children without caries was -5.0% to 64% (14.6%). The range (median) of mean change in decayed, missing, and filled primary/permanent teeth was 0.5 to 4.4 (2.25) teeth. A dose-dependent increase in dental fluorosis was found. At a fluoride level of 1 ppm an estimated 12.5% (95% confidence interval 7.0% to 21.5%) of exposed people would have fluorosis that they would find aesthetically concerning. CONCLUSIONS: The evidence of a beneficial reduction in caries should be considered together with the increased prevalence of dental fluorosis. There was no clear evidence of other potential adverse effects. |
Medline |
|
| 1999 |
Allolio B, Lehmann R |
Drinking water fluoridation and bone. |
Exp Clin Endocrinol Diabetes 1999; 107(1): 12-20 |
waterfluoride |
Drinking water fluoridation has an established role in the prevention of dental caries, but may also positively or negatively affect bone. In bone fluoride is incorporated into hydroxylapatite to form the less soluble fluoroapatite. In higher concentrations fluoride stimulates osteoblast activity leading to an increase in cancellous bone mass. As optimal drinking water fluoridation (1 mg/l) is widely used, it is of great interest, whether long-term exposition to artificial water fluoridation has any impact on bone strength, bone mass, and -- most importantly -- fracture rate. Animal studies suggest a biphasic pattern of the effect of drinking water fluoridation on bone strength with a peak strength at a bone fluoride content of 1200 ppm followed by a decline at higher concentrations eventually leading to impaired bone quality. These changes are not paralleled by changes in bone mass suggesting that fluoride concentrations remain below the threshold level required for activation of osteoblast activity. Accordingly, in most epidemiological studies in humans bone mass was not altered by optimal drinking water fluoridation. In contrast, studies on the effect on hip fracture rate gave conflicting results ranging from an increased fracture incidence to no effect, and to a decreased fracture rate. As only ecological studies have been performed, they may be biased by unknown confounding factors -- the so-called ecological fallacy. However, the combined results of these studies indicate that any increase or decrease in fracture rate is likely to be small. It has been calculated that appropriately designed cohort studies to solve the problem require a sample size of >400,000 subjects. Such studies will not be performed in the foreseeable future. Future investigations in humans should, therefore, concentrate on the effect of long-term drinking water fluoridation on bone fluoride content and bone strength. |
Medline |
|
| 1999 |
Jones G, Riley M, Couper D, Dwyer T |
Water fluoridation, bone mass and fracture: a quantitative overview of the literature. |
Australian & New Zealand Journal of Public Health 23(1): 34-40, 1999 |
waterfluoride |
OBJECTIVE: To use the technique of meta-analysis to address the following research questions: Is water fluoridation associated with altered fracture risk at a population level and are the differences between studies consistent with confounding or chance variation between studies? METHOD: The data sources utilised were Medline 1966-97, reviews and bibliographies. The search terms were fluoridation, bone mass and/or fracture. We included all observational studies published in English relating water fluoridation to bone mass and/or fracture in the initial assessment. RESULTS: Water fluoridation had no evident effect on fracture risk (RR 1.02, 95% CI 0.96-1.09, n = 18 studies). There was marked heterogeneity between studies which could be explained, in part, by the combination of gender, urbanicity and study quality (R2 0.25, p = 0.05, weighted analysis). CONCLUSIONS: Water fluoridation both at levels aimed at preventing dental caries and, possibly, at higher naturally occurring levels appears to have little effect on fracture risk, either protective or deleterious, at a population level. The small effect on bone mass seen in studies performed at the individual level is consistent with this finding. Variation between studies is also likely to be due to differences in the distribution of other recognised fracture risk factors between different populations. Confirmation of these findings is required in large studies performed at the individual level. |
Medline |
|
| 1989 |
White BA, Antczak-Bouckoms AA, Weinstein MC |
Issues in the economic evaluation of community water fluoridation |
J Dent Educ 1989; 53(11): 646-57 |
waterfluoride |
|
|
|