Neuro-medical complications of fluoride toxicity among populations living in fluoride endemic region of the Ethiopian Rift Valley

Abstract Background: Fluorosis is endemic in many countries of Asia, South America and Africa. In Africa, the countries located across the Great East African Rift Valley, including Ethiopia are a hotspot for fluorosis. While excessive and chronic exposure to fluoride causes dental and skeletal fluorosis, emerging studies have shown its adverse health effects in cognition, memory, learning and the function of Central Nervous System. Method: We conducted a study on 318 individuals living in rural villages located in fluoride endemic areas of the Ethiopian Rift Valley. Drinking water samples were collected from 23 community well sites, and analyzed for fluoride concentrations. Detailed clinical evaluations of skeletal fluorosis, neurologic history, and physical examination were performed in the study participants. Results: The mean age of the study participants was 28.0±14.9 years. About 80% of the participants were from the communities with fluoride level >2 mg/L. The mean fluoride level in drinking water samples was 6.8±4.3 (range: 0.3 to 15.5 mg/L). Male accounted 55.7% of the subjects participated. Among the neurologic complications, headache, fatigue, and paresthesia accounted for 67%, 56.3%, and 37.5%, respectively. Urinary incontinence, muscle atrophy and crippling neuroflourosis were observed only in a few of our study participants (< 5%). Headache disorders had statistically significant association with high fluoride levels. Clinical anemia was observed in 49.7% of our study population. Conclusion: Fluorosis has significant socio-economic and psychological impacts on productive segment of a population. Unlike previously reported findings, where neurological complications were largely attributed to compressive radioculomyelopathy, this study highlighted toxic level of fluoride might also results in non-compressive neurological and medical complications. We therefore recommend conducting further large scale epidemiological study to confirm these findings.