Analysis of Groundwater Fluoride Contamination and Dental Fluorosis in Communities in Yobe State, North East Nigeria

Naturally occurring fluoride in groundwater is a geo-medical hazard in the Lake Chad Basin geological zone, and its health consequences, particularly dental and skeletal fluorosis, constitute a significant environmental health burden requiring empirical characterization. This study analyzed groundwater fluoride contamination and its relationship with dental fluorosis prevalence in communities in Bade and Geidam local government areas, Yobe State, North East Nigeria. Forty-two groundwater sources were sampled and analyzed for fluoride, total dissolved solids, pH, and alkalinity using standard APHA methods. A cross-sectional dental examination was conducted among 620 school-aged children aged six to fifteen years, using the Thylstrup and Fejerskov (TF) index to grade fluorosis severity. Multiple regression analysis was employed to assess the contribution of fluoride ingestion levels, duration of residence, and dietary calcium intake to fluorosis severity scores. Results showed that fluoride concentrations exceeded the WHO guideline of 1.5 mg/L in sixty-seven percent of sampled sources, with maximum values reaching 6.8 mg/L. Dental fluorosis prevalence among examined children was seventy-three percent, with moderate to severe fluorosis recorded in forty-four percent of affected children. A significant dose-response relationship was established between fluoride concentration and fluorosis severity. Dietary calcium deficiency was found to be a significant effect modifier, exacerbating fluorosis severity at equivalent fluoride exposures. The study recommends urgent implementation of community defluoridation systems, nutritional supplementation, and geo-medical surveillance networks in the Lake Chad Basin region. Keywords: groundwater fluoride, dental fluorosis, Yobe State, defluoridation, geo-medical hazard.