Buddhi N. T. Fernando 1,2 ,Nishantha Nanayakkara 3 ,Rohana Chandrajith 4 ,Hemalika T. K. Abeysundara 5 and Dulanjali Herath 6
1 Centre for Education, Research and Training on Kidney Diseases, University of Peradeniya, Peradeniya 20400, Sri Lanka
2 Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Ruhuna, Walahanduwa, Galle 80000, Sri Lanka
3 Transplant and Dialysis Unit, National Hospital Kandy, Kandy 20000, Sri Lanka
4 Department of Geology, Faculty of Science, University of Peradeniya, Peradeniya 20400, Sri Lanka
5 Department of Statistics and Computer Science, Faculty of Science, University of Peradeniya, Peradeniya 20400, Sri Lanka
6 Centre for Research, National Hospital, Kandy 20000, Sri Lanka
Abstract
Chronic kidney disease of uncertain etiology (CKDu) has emerged with growing evidence linking it to environmental exposures. This case–control study aimed to evaluate serum and urine trace elements (TEs) in CKDu patients, comparing them with those from control groups from endemic and non-endemic regions. TEs were analyzed in 406 participants (CKDu = 75, endemic CKD (ECKD) = 82, non-endemic CKD (NECKD) = 85, endemic control (EC) = 79, non-endemic control (NEC) = 85 using Inductively Coupled Plasma Mass Spectrometry. Means ± standard deviations were compared via the t-test and categorical variables by the chi-square test. Compared to non-endemic groups, Al, Mn, Ni, Cu, Cd, and Ba in serum and urine were significantly higher in endemic areas. CKDu patients showed elevated serum V, Cr, Zn, As, and U and urinary Cr, Mn, Fe, Co, Ni, and Rb compared to ECKD. Compared to NEC, CKDu patients had higher serum Zn, As, and Ba and urinary Al, Cr, Mn, Fe, Co, Ni, and Cu. Significant increases in serum V, Zn, As, Cd, Ba, and U and urinary V, Cr, Mn, Co, Ni, Rb, and Sr were noted in CKDu vs. NECKD. Elevated serum Al, Cr, Mn, Fe, Co, etc., and urinary Be, V, Zn, Se, etc., were observed in EC vs. CKDu. Urinary TEs positively correlated with eGFR, suggesting tubular dysfunction or prolonged exposure. Serum Se, a known reno-protective TE, was low in CKDu and ECKD. This study highlights that TE levels were high not only due to exposure but also depending on kidney health. Identified group-specific TEs may be causative in CKDu, having adverse health outcomes in some groups while potentially being protective in healthy groups.
Keywords: trace elements; chronic kidney disease of uncertain etiology; serum; urine; inductively coupled plasma mass spectrometry; environmental exposure
