Kidney toxicity of fluorides-A biochemical evaluation of renal function markers in adults residing in fluoride endemic areas of YSR Kadapa district

Introduction

A cross-sectional study assessed the relationship between fluoride exposure and renal function in adults residing in endemic fluoride villages of the YSR Kadapa district.

Materials and method

320 subjects were randomly selected from the willing participants of 659 adults based on selection criteria. The study subjects were grouped based on age into Group A (Adults aged between 21 and 40years) and Group B (Adults aged between 41 and 60years). Fluoride levels in consumable water samples and urine samples were measured using a fluoride ion meter. Serum creatinine and blood urea nitrogen levels were analyzed as markers of renal function in blood samples collected from willing participants.Pearson's correlation coefficient,Chi-square test of independence, and Student's t-test were employed for statistical analyses to determine significance level at a p-value <0.05. Results-The mean fluoride levels in water samples were 1.5 mg/l to 4.1 mg/l, with a prevalence of fluorosis of 60.6 % among the study subjects. A strong positive correlation was found between renal function markers with water fluoride consumption (p = 0.0019 for creatinine; p = 0.0416 for urea nitrogen) and urinary fluoride excretion (p = 0.005). No statistically difference was observed in renal function markers between subjects with fluorosis and those without fluorosis in two different age groups (p = 0.7258,p = 0.4505) and (p = 0.759,p = 0.0868). However, there was a statistically significant difference in renal function markers between two age groups ie., 21–40years and 41–60years (p < 0.0001) irrespective of fluorosis.

Conclusion

The findings concluded that increased fluoride consumption may be nephrotoxic, with the degree of individual damage related to the quantity and duration of fluoride exposure, but not necessarily to the presence or absence of fluorosis.