Community water fluoridation is widely accepted by the scientific community to be the safest, most cost effective, and most equitable method to prevent tooth decay in children and adults. The Washington State Board of Health recommends an optimal level for fluoride in drinking water of 0.7 mg/L; at these levels there is no evidence of negative health outcomes or toxicity. Spokane is the largest city in the State of Washington without fluoridated drinking water. This brief summarizes recent scientific literature, provides local contextual details, and offers a characterization of predicted health impacts of water fluoridation. – Spokane Regiona Health District

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Spokane Community Water Fluoridation

Executive Summary

Community water fluoridation is widely accepted by the scientific community to be the safest, most cost effective, and most equitable method to prevent tooth decay in children and adults. The Washington State Board of Health recommends an optimal level for fluoride in drinking water of 0.7 mg/L; at these levels there is no evidence of negative health outcomes or toxicity. Spokane is the largest city in the State of Washington without fluoridated drinking water. This brief summarizes recent scientific literature, provides local contextual details, and offers a characterization of predicted health impacts of water fluoridation.

Background

Healthy teeth and mouths play a surprisingly important role in people’s ability to learn and thrive. Everyday activities such as smiling, eating, speaking, concentrating, and sleeping can be painful and embarrassing for individuals with unhealthy teeth and mouths, impacting confidence, attendance and performance at school and work, and long-term health outcomes.¹ Children with chronic tooth pain have difficulty learning and eating healthy.² Studies link tooth disease early in life with lower graduation rates, lower lifetime earnings, and lower quality of life^_.3 Adults with missing, visibly decayed, and painful teeth and mouths have trouble with speech, social connections, and finding and keeping jobs.4 Cavities, gum disease, and other oral health issues also carry a financial burden, costing American taxpayers billions of dollars every year.⁵

Fortunately, tooth decay and gum disease are largely preventable. Over 50 years of epidemiological studies support the naturally-occurring mineral fluoride as the most effective way to prevent cavities.⁶ Fluoride works by strengthening tooth enamel and preventing its breakdown—a process called demineralization.⁷ Children who visit a dental care provider today can effectively prevent tooth decay with a professionally applied fluoride varnish.⁸ Not all children have equal access to dental care though, and kids without a regular dentist miss this important preventive step.

Due to its health and economic benefits, community water fluoridation is considered to be the most effective andequitable public health measure for the prevention of  tooth decay.⁹ Providing consistent, low-levels of fluoride in drinking water—called community water fluoridation—can reduce tooth decay by 25% in children and adults and save communities an average of $20 for every dollar invested.¹⁰ Cities and states began adding fluoride to drinking water over 70 years ago; today nearly three out of four people in the United States access fluoridated water in their homes.¹¹ Though studies show that lower income children still have more cavities than children in higher income families regardless of level of fluoride, this approach allows all children barrier-free access to cavity prevention regardless of dental coverage.¹² In fact, the American Public Health Association summarized, “Children with the greatest dental need and who are at highest risk for tooth decay benefit the most from water fluoridation.”¹³

Despite widespread scientific support for community water fluoridation, some individuals oppose adding fluoride todrinking water. Oral fluoride does come with a  minimal risk of a condition called enamel fluorosis.¹⁴ Fluorosis results from high fluoride levels during the time that tooth enamel is forming. Cases of fluorosis range from mild—white specks on the teeth—to severe—rough, pitted teeth surfaces.¹⁵ Most cases of fluorosis in the United States are mild and don’t have serious health impacts, though children affected by fluorosis might be judged by their peers or afraid to smile and show their teeth.¹⁶

The US Environmental Protection Agency’s current enforceable drinking water standard for fluoride—the maximum amount allowed in public water systems—is 4.0 milligrams per liter (mg/L), though water systems must notify customers if levels exceed 2.0 mg/L.¹⁷ The federal Department of Health and Human Services and the Washington State Board of Health recommend an optimal level for fluoride in drinking water of 0.7 mg/L.¹⁸ These lower recommendations take into account the total daily intake of fluoride from various sources for children under age 8 (the age group most at risk for fluorosis). Infants may be at an increased risk for overexposure to fluoride if fluoridated water is used to reconstitute formula.¹⁹ Other sources of exposure to fluoride, such as mouthwash or toothpaste, can also increase a child’s risk of fluorosis.²⁰ Children exposed between ages two and three seem most vulnerable to fluorosis.²¹

Mild to moderate dental fluorosis is common at levels between 0.7 mg/L and 2 mg/L.²² At very high levels, fluoride can cause skeletal defects, thyroid problems, and slightly lower IQ scores.²³ However, studies documenting these negative outcomes are limited to developing countries where fluoride levels in groundwater exceed the recommended level in the United States.²⁴ One systematic review found weak evidence of decreased IQ scores, early kidney injury, and thyroid effects in children, and atherosclerosis, hypertension, and cardiac dysfunction in adults at fluoride levels over 2 mg/L, but many of these studies did not control for other factors that could cause similar outcomes such as other groundwater contaminants or socio-economic status.²⁵ One systematic review that considered studies on animals, sometimes used as an imperfect proxy for humans, found low to moderate evidence of memory and learning impairments at fluoride levels greater than 0.7 mg/L.²⁶ There is no strong evidence of negative health effects at or below 0.7 mg/L, the optimal fluoride levels set by the Washington State Board of Health.²⁷

Local Context

Fluoridated water systems serve over half of Washington State residents.²⁸ According to Smile Spokane, Spokane is the largest city in the state without fluoridated water. Nearby, the City of Cheney and Fairchild Airforce Base add fluoride to their public water supply, as do Boise, Yakima, and Tacoma.²⁹ The City of Spokane monitors levels of naturally occurring fluoride in groundwater throughout the city. In 2016, their survey of seven well stations measured levels ranging from 0.01 to 0.5 mg/L.³⁰

More than six out of every ten third graders in Spokane had a cavity in a permanent tooth in 2015, compared to 53% in the state of Washington as a whole, and nearly one in six have rampant decay affecting seven or more teeth. Dental decay was higher among Black, American Indian and Alaskan Native, Asian, Pacific Islander, and Hispanic children than white children. Lower income children—those eligible for free- and reduced-price school meals—similarly were more likely to have cavities than their higher-income peers, according to local data (Figure 1).³¹

Figure 1. Low-income and children of color have disproportionately more tooth decay – see pdf  for graphic

Percent of third grade students who have had a cavity in a primary or permanent tooth, by race, 2015

In Spokane County, low-income adults, people of color, and those with lower educational attainment are significantly less likely to have visited a dentist in the last 12 months and more likely to be missing six or more teeth due to decay.³²

Characterization of Predicted Health Effects

Health Outcomes	Likelihood	Quality of Evidence	Affected or Vulnerable Population	Equity Impact
Reduced tooth decay	Definite	Strong	Low-income individuals and people of color; individuals without access to regular dental care	Reduces inequities
Mild dental fluorosis	Probable	Strong	Individuals exposed to multiple sources of low levels of fluoride	None
Moderate dental fluorosis	Possible	Strong	Individuals exposed to multiple sources of low levels of fluoride	None
Severe dental fluorosis	Unlikely	Strong	Individuals exposed to multiple sources of high levels of fluoride	None
Skeletal fluorosis	Very unlikely	Strong	Not predicted	None
Thyroid impairment	Very unlikely	Strong	Not predicted	None
Neurocognitive impairment	Very unlikely	Moderate	Not predicted	None
Kidney injury	Very unlikely	Moderate	Not predicted	None
Heart injury	Very unlikely	Moderate	Not predicted	None

 

Endnotes

1 US Department of Health and Human Services, Public Health Service, Office of the Surgeon General. Oral health in America: A report of the Surgeon General. Rockville, MD: National Institutes of Health, National Institute of Dental and Craniofacial Research, 2000; Ruff, RR, et al. Oral health, academic performance, and school absenteeism in children and adolescents: A systematic review and meta-analysis. Journal of the American Dental Association, 2016; 1939: 150(2), 111–121.e4. DOI: https://doi.org/10.1016/j.adaj.2018.09.023.

2 Griffin SO, et al. Vital Signs: Dental Sealant Use and Untreated Tooth Decay Among U.S. School-Aged Children. MMWR Morbidity and Mortality Weekly Report, 2016; 65:1141-1145. DOI: http://dx.doi.org/10.15585/mmwr.mm6541e1.

3 Ruff, RR, et al. Oral health, academic performance, and school absenteeism in
children and adolescents: A systematic review and meta-analysis.

4 Centers for Disease Control and Prevention. Oral Health Conditions. Oral Health, 2020. Accessed July 7, 2020
https://www.cdc.gov/oralhealth/conditions/index.html.

5 Ibid.

6 Community Preventive Services Task Force. Task Force Finding and Rationale Statement. Oral Health: Preventing Dental Caries, Community Water Fluoridation, 2017. Accessed online July 21, 2020.  https://www.thecommunityguide.org;
Bansal, A, et al. Recent Advancements in Fluoride: A Systematic Review. Journal of International Society of Preventive and Community Dentistry, 5(5), 2015, DOI:
https://dx.doi.org/10.4103%2F2231-0762.165927;
Chou, R, et al. Prevention of Dental Caries in Children Younger Than 5 Years Old: Systematic Review to Update the U.S. Preventive Services Task Force Recommendation. Evidence Syntheses, No. 104, Agency for Healthcare Research and Quality, 2014, https://www.ncbi.nlm.nih.gov/books/NBK202090/.

7 Carey, CM. Focus on Fluorides: Update on the use of fluoride for the
prevention of dental caries. Journal of Evidence-Based Dental Practice, 2014:
14 Suppl: 95-102. DOI: https://dx.doi.org/10.1016%2Fj.jebdp.2014.02.004.

8 Chou, R, et al. Prevention of Dental Caries in Children Younger Than 5 Years
Old.

9 Community Preventive Services Task Force. Task Force Finding and Rationale
Statement; Cagetti, M G, et al. A Systematic Review on Fluoridated Food in Caries Prevention. Acta Odontologica Scandinavica, 71(3–4), 2013, pp. 381–87, DOI: https://dx.doi.org/10.3109/00016357.2012.690447;
Chong, L Y, et al. Slow-Release Fluoride Devices for the Control of Dental Decay.
Cochrane Database of Systematic Reviews, 2018(3), 2018, DOI:
https://dx.doi.org/10.1002/14651858.CD005101.pub4;
de Silva, A M, et al. Community-Based Population-Level Interventions for Promoting Child Oral Health. Cochrane Database of Systematic Reviews, 2016(9), 2016, DOI: https://dx.doi.org/10.1002/14651858.CD009837.pub2;
Marinho, V, et al. Fluoride Gels for Preventing Dental Caries in Children and Adolescents. Cochrane Database of Systematic Reviews, 2015(6), 2015, DOI:
https://dx.doi.org/10.1002/14651858.CD002280.pub2;
Marinho, V, et al. Fluoride Mouthrinses for Preventing Dental Caries in Children and Adolescents. Cochrane Database of Systematic Reviews, 2016(7), 2016, DOI: https://dx.doi.org/10.1002/14651858.CD002284.pub2;
Moynihan, P., et al. Systematic Review of Evidence Pertaining to Factors That Modify Risk of Early Childhood Caries. Journal of Dental Research Clinical and Translational Research, 4(3): 202-16, 2019, DOI:
https://dx.doi.org/10.1177/2380084418824262;
Yeung, C, et al. Fluoridated Milk for Preventing Dental Caries. Cochrane
Database of Systematic Reviews, 2015(9), 2015, DOI:
https://dx.doi.org/10.1002/14651858.CD003876.pub4;
Ran, T, and Chattopadhyay, S. Economic Evaluation of Community Water Fluoridation: A Community Guide Systematic Review. American Journal of Preventive Medicine, 50(6): 790–96, 2016 DOI:
https://dx.doi.org/10.1016/j.amepre.2015.10.014.

10 Department of Health and Human Services. Statement on the Evidence
Supporting the Safety and Effectiveness of Community Water Fluoridation.
Centers for Disease Control and Prevention, Atlanta, GA, 2018.

11 Carey, C M. Focus on Fluorides: Update on the Use of Fluoride for the Prevention of Dental Caries. Journal of Evidence-Based Dental Practice, 14(SUPPL), 2014, pp. 95–102, DOI: https://dx.doi.org/10.1016/j.jebdp.2014.02.004.

12 Goodarzi, F, et al. Prevalence of Dental Caries and Fluoride Concentration of
Drinking Water: A Systematic Review. Dental Research Journal, 12(3): 163–68,
2017, DOI: https://dx.doi.org/10.4103/1735-3327.208765.

13 American Public Health Association. “Community Water Fluoridation
in the United States.” Policy Statement, 2008,
https://www.apha.org/policies-and-advocacy/public-health-policy-statements/policydatabase/2014/07/24/13/36/community-water-fluoridation-in-the-unitedstates.

14 Chou, R, et al. Prevention of Dental Caries in Children Younger Than 5 Years
Old: Systematic Review to Update the U.S. Preventive Services Task Force Recommendation. Evidence Syntheses, No. 104, Agency for Healthcare Research and Quality, 2014, https://www.ncbi.nlm.nih.gov/books/NBK202090/.

15 Carey, C M. Focus on Fluorides.

16 Akuno, M. H., et al. Factors Influencing the Relationship between Fluoride in
Drinking Water and Dental Fluorosis: A Ten-Year Systematic Review and Meta-
Analysis. Journal of Water and Health, 17(6): 845–62, 2019, DOI:
https://dx.doi.org/10.2166/wh.2019.300.

17 United States Environmental Protection Agency. Questions and Answers on
Fluoride. 2011.

18 Washington State Department of Health. Fluoridation of Drinking Water.
Drinking Water. Accessed July 24, 2020
https://www.doh.wa.gov/CommunityandEnvironment/DrinkingWater/FluorideinDrinkingWater.

19 Bansal, A, et al. Recent Advancements in Fluoride: A Systematic Review. Journal of International Society of Preventive and Community Dentistry, 5(5), 2015, DOI: https://dx.doi.org/10.4103/2231-0762.165927; Carey, C M, Focus on Fluorides.

20 Chou, R, et al. Prevention of Dental Caries in Children Younger Than 5 Years
Old.

21 Ibid.

22 Goodarzi, F, et al. The Prevalence of Dental Fluorosis and Exposure to Fluoride in Drinking Water: A Systematic Review. Journal of Dental Research, Dental Clinics, Dental Prospects, 10(3): 127-35, 2016,DOI:
https://dx.doi.org/10.15171/joddd.2016.021.

23 Akuno, M. H., et al. Factors Influencing the Relationship between Fluoride in
Drinking Water and Dental Fluorosis.

24 Akuno, M. H., et al. Factors Influencing the Relationship between Fluoride in Drinking Water and Dental Fluorosis; Chaitanya, N, et al. A Systematic Analysis on Possibility of Water Fluoridation Causing Hypothyroidism. Indian Journal of Dental Research, vol. 29, no. 3, 2018, pp. 358–63, DOI:
https://dx.doi.org/10.4103/ijdr.IJDR_505_16;
Choi, A L., et al. Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis. Environmental Health Perspectives, 120(10): 1362–68, National Institute of Environmental Health Sciences, 2012, DOI:
https://dx.doi.org/10.1289/ehp.1104912;
Chou, R, et al. Prevention of Dental Caries in Children Younger Than 5 Years Old;
Demelash, H, et al. Fluoride Concentration in Ground Water and Prevalence of Dental Fluorosis in Ethiopian Rift Valley: Systematic Review and Meta-Analysis. BioMed Central Public Health, 19(1298), 2019, DOI:
https://dx.doi.org/10.1186/s12889-019-7646-8;
Duan, Q, et al. Association Between Water Fluoride and the Level of Children’s Intelligence: A Dose–Response Meta-Analysis. Public Health, 154(2018):87–97, 2018 DOI: https://dx.doi.org/10.1016/j.puhe.2017.08.013.

25 Limón-Pacheco, J H, et al. Potential Co-Exposure to Arsenic and Fluoride and
Biomonitoring Equivalents for Mexican Children. Annals of Global Health,
84(2): 257–73, 2018, DOI: https://dx.doi.org/10.29024/aogh.913.

26 National Toxicology Program. National Toxicology Program Research Report on Systematic Literature Review on the Effects of Fluoride on Learning and Memory in Animal Studies: Research Report 1, 2016,
http://www.ncbi.nlm.nih.gov/pubmed/31944639.

27 Council, National Research. Fluoride in Drinking Water, National Academies
Press, 2006, DOI: https://dx.doi.org/10.17226/11571;
Department of Health and Human Services. Statement on the Evidence Supporting the Safetyand Effectiveness of Community Water Fluoridation; Guth, S, et al. Toxicity of Fluoride: Critical Evaluation of Evidence for Human Developmental
Neurotoxicity in Epidemiological Studies, Animal Experiments and In Vitro Analyses. Archives of Toxicology, 94(5): 1375-415, 2020, DOI:
https://dx.doi.org/10.1007/s00204-020-02725-2.

28 Washington State Department of Health. Statement on Community Water
Fluoridation. Olympia, WA, 2015.

29 Washington State Department of Health. Fluoride Communities. Fluoride in Drinking Water. Accessed July 27, 2020
https://www.doh.wa.gov/CommunityandEnvironment/DrinkingWater/FluorideinDrinkingWater.

30 Greenlund, D. Report on City of Spokane Drinking Water for 2015. City of
Spokane – Environmental Programs, 2016.

31 Spokane Regional Health District. Dental Decay—Children. County Health
Insights. Accessed July 20, 2020 https://countyhealthinsights.org.

32 Spokane Regional Health District. Dental Check-Up. County Health Insights.
Accessed July 29, 2020 https://countyhealthinsights.org; Spokane Regional Health District. Tooth Loss—Adult. County Health Insights. Accessed July 29, 2020 https://countyhealthinsights.org.

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Spokane Regional Health

1101 W. College Ave., Spokane, WA 99201 | 509.324.1500 | TDD 509.324.1464 |
https://srhd.org/

Created: August 2020