Abstract:
Background
Chronic Kidney Disease of uncertain aetiology (CKDu) is endemic among farming
communities in the dry zone of SriLanka where ground water fluoride is known to be higher
than recommended levels.
Objectives
To compare the serum and urine fluoride levels in CKDu patients with healthy controls
Methods
All biopsy proven CKDu patients (n=116) at renal clinic (from 2015 to 2017) and healthy
controls (n=77) from Girandurukotte and Wilgamuwa were recruited. Serum and urine
fluoride levels were determined using ion selective electrode method.
Results
The serum fluoride concentration ranged between 0.47 and 9.58 mg/L while urine fluoride
varied between 0.45 and 6.92 mg/L in CKDu patients. Among patients, urine fluoride levels
showed a significant difference with the CKDu stage while no difference was observed
between males and females and defined age groups (> 40years and< 40 years). In endemic
controls, serum fluoride concentration ranged between 0.51 and 1.92 mg/L while urine
fluoride varied between 0.36 and 3.80 mg/L. Fluoride in serum and urine was significantly
higher in CKDu patients (p < 0.05 and p < 0.05, respectively) than in endemic control group.
In receiver operating characteristics (ROC) plots of fluoride in serum and urine, areas under
the curves (AUC) were 0.682 and 0.628, respectively when analyzed CKDu patients against
endemic controls.
Conclusion
Fluoride in serum in CKDu cases might be due to exposure to high fluoride levels, possibly
through drinking water while higher urinary fluoride excretion would be due to kidney
failure, suggesting the possible nephrotoxic role of high fluoride exposure.
