Fluoride Action Network


Prolonged exposure to higher concentrations of fluoride (> 1.5 mg/L) is associated with dental and skeletal fluorosis. The effects of fluoride on dental and skeletal system have been studied extensively; however, the neurological consequences of fluoride in population-based studies are limited. The study aims to assess the epidemiology of neurological and other manifestations of fluorosis among rural populations living in the Main Ethiopian Rift valley. In this cross-sectional study, we enrolled 316 individuals from 23 rural communities in the Main Ethiopian Rift valley. Fluoride concentration was measured in drinking water samples collected from 23 community wells. Association between fluoride concentrations and clinical features of fluorosis was assessed using student t test, chi square, multivariable regression using adjusted odds ratio (OR). The mean fluoride concentration in the drinking water was 6.8 ± 4.3 mg/L (range: 0.3–15.5 mg/L). At least one clinical sign of skeletal fluorosis was observed in 54.4% (n = 175) of the study participants. Headache and joint pain reported by 67.1% and 56.3% of the participants as the most common neurological manifestation, and skeletal fluorosis symptom, respectively. The mean fluoride level was higher for those individuals who reported paresthesia compared to those with no-paresthesia. Loss of appetite, constipation, and fatigue were reported by 48.0%, 45.6%, and 56.6% of the participants, respectively. Signs of crippling fluorosis were observed in small proportion (1.6%) of the participants. Individuals who reported headache are most likely exposed to higher fluoride concentrations in drinking water compared to those reported no-headache (p < 0.001). The study demonstrates high prevalence of neuro-medical manifestations of fluorosis in population living in the Main Ethiopian Rift valley. Fluoride concentration in drinking water and joint pain were independent predictors of fluorosis.

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*Original abstract online at https://link.springer.com/article/10.1007%2Fs10653-021-01016-8


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F? : Fluoride
Mg/L: Milligram per liter
WHO: World Health Organization


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We thank all the children and parents who participated in this study, and the local water bureaus for their help in recruiting them as well as guiding us during the field work. The content expressed in this paper is the responsibility of the authors and does not necessarily reflect the official views of the NIH.


This is part of an ongoing cohort study in the Ethiopia Rift Valley with the goal of understanding the health impacts of fluoride in teeth, cartilage, joint, and bone mineralized tissues and associated neurologic complications of fluoride related health problems in children and adults. We are grateful for the funding from the NIEHS’s career development grant (K99/R00 ES023472).

Author information



BAA and TR: Design of study concept, conducted the field work, analytical data analysis and interpretation, wrote the manuscript, and contributed immensely on manuscript review. RT and YMY: Design of study concept, field work assistance, critical revision of the manuscript for important intellectual content.

Corresponding author

Correspondence to Biniyam A. Ayele.

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Ayele, B.A., Godebo, T.R., Tekle-Haimanot, R. et al. Neuro-medical manifestations of fluorosis in populations living in the Main Ethiopian Rift Valley. Environ Geochem Health (2021). https://doi.org/10.1007/s10653-021-01016-8

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  • Fluoride
  • Drinking water
  • Skeletal fluorosis
  • Neurologic complications
  • Main ethiopian rift valley

*Original abstract online at https://link.springer.com/article/10.1007%2Fs10653-021-01016-8