Abstract

The protective effect of community water fluoridation (CWF) on caries is established, but secular changes may modify its impact. Relationships with adverse health outcomes have also been alleged. We aimed to determine the association between concentrations of fluoride in public water supplies (PWS) and dental caries indicators, and certain adverse health-outcomes to monitor the health effects of CWF in England.We estimated exposure to CWF and PWS fluoride concentrations from national PWS monitoring data, using Geographic Information Systems and water supply boundaries. We categorised mean period exposure into <0.1, 0.1-<0.2, 0.2-<0.4, 0.4-<0.7, and >0.7 mg/l. We obtained area-level health outcome and confounder data from routine data sources. We used multivariable regression to determine the association between fluoride and health outcomes.The association between fluoride level and caries prevalence/severity varied by quintile of socioeconomic status (SES) (p<0.001 for interaction). Odds of caries, and of severe caries in five-year-olds, fell with increasing category of fluoride concentration in each quintile of SES (p<0.001 to p<0.003). There was a negative trend between increasing fluoride concentration and dental extractions (p<0.001). There were sporadic positive associations (p<0.05) between varying fluoride concentrations and Down’s syndrome and kidney stones, but without evidence for a trend or threshold. There was a negative association with bladder cancer at the highest fluoride concentration. The association with hip fracture varied in direction by age (p<0.001), with a small positive association (RRs 1.03-1.05, p=0.08 or below) in adults aged 80 years+ at each fluoride concentration relative to <0.1mg/l. There was no strong evidence of an association with osteosarcoma. Exposure to fluoride in PWS appears highly protective of caries and caries extractions. Our findings did not provide clear evidence of an association with the adverse health outcomes.

Authors affiliations (Abstract number P02.3141 on page 1520 of the 2018 ISEE abstracts):

David J. Roberts², Giovanni S. Leonardi¹, John Morris³, Neville Verlander⁴, Nick Young⁵, Vicky Massey⁶, David Wilcox⁷, Semina Makhani⁴, Stephen Robjohns⁸, Helen Smith⁸, Ovnair Sepai⁸, Ayoub Saei⁴, Gill Davies⁷, Diane Edwards⁶, Andrew Wood⁶, Mark Reacher⁹, Sandra White⁴, Tony Fletcher¹.

1. Environmental Epidemiology, Centre for Radiation Chemical and Environmental Hazards, Public Health England, Didcot, United Kingdom.
2. Field Epidemiology Training Programme, Colindale, Public Health England, London, United Kingdom.
3. University of Birmingham, Birmingham, United Kingdom.
4. Public Health England, London, United Kingdom.
5. Public Health England, Totnes, United Kingdom.
6. Public Health England, Birmingham, United Kingdom.
7. Public Health England, Manchester, United Kingdom.
8. Toxicology, Public Health England , Chilton, United Kingdom.
9. Public Health England, Cambridge, United Kingdom.

*Abstract also online at https://ehp.niehs.nih.gov/doi/10.1289/isesisee.2018.P02.3141

Note: Also see another abstract on fluoridation presented by Tony Fletcher at the ISEE Conference: Possible Benefits and Adverse Effects of Fluoridation in England, 2018 Public Health England Report.

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