A study on the possible impacts of groundwater fluoride on urinary and serum fluoride among individuals afflicted with dental fluorosis

A case-control study was performed from a fluoride ion (F) endemic region in West Bengal, India, where safe piped drinking water is supplied at present. It aimed to assess F exposure status among 129 subjects (cases=67 and controls=62) of three endemic villages in the Birbhum district using the biomarkers of urinary F (UF) and serum F (SF) besides groundwater F (GF). Mean UF and SF concentrations were not significantly different between the cases and the controls. Spearman's correlation showed a moderately low positive correlation of UF with both SF and GF and a very low positive correlation of SF with GF among all the subjects. The study further investigated relationship between UF, SF, and body mass index (BMI) of the subjects through principal component analysis (PCA). PCA found a positive correlation between UF, SF, and GF concentrations and a negative correlation of BMI with these parameters. Significant differences of variance (p=0.00) were observed between UF and SF concentrations of subjects in two-way analysis of variance (ANOVA). The study findings indicate that both the control and case groups were still getting exposed to unsafe water sources with more than the desired level of F. The study underlines the importance of measuring F in the body fluids, as well as the F level in drinking water, in assessing the correct exposure level among the populations in the endemic regions