Fluoride Action Network


The effects of renal function on urinary fluoride clearance and serum inorganic fluoride concentration were studied. Laboratory determinations including (1) creatinine clearance rate (CCR), (2) serum inorganic fluoride concentration, and (3) urinary fluoride concentration, were made on 122 hospital patients. Subjects were then divided into impaired, questionable and normal creatinine clearance groups. Respectively, the age adjusted mean serum inorganic fluoride concentrations were 0.035, 0.031 and 0.027 ug F/ml for males and 0.033, 0.026 and 0.029 ug F/ml for females. In neither sex were the differences among the three group means statistically significant. The mean urinary 24 hr fluoride excretions in the three groups were 0.30, 0.56 and 0.87 mg respectively for males and 0.24, 0.51 and 0.70 mg for females. For both sexes, the differences among the three group means were statistically significant (p < 0,01). The results suggest that in regions with low fluoride concentrations in the drinking water (0.1 ppm F), impaired creatinine clearance in human subjects is associated with a reduction in urinary clearance of fluoride without simultaneous elevation of serum inorganic fluoride concentration.