Abstract
BACKGROUND: Chronic kidney disease (CKD) patients are prone to osteoporosis (OP) and they had significant oxidative stress. The relationship between oxidative stress (OS) and bone mineral density (BMD) in CKD is not entirely clear. The investigation of this relation is of pronounced importance in decreasing the occurrence of osteoporosis among CKD cases. OBJECTIVES: To evaluate the association between BMD and OS in CKD patients. METHODS: We performed a case-control study, including 150 adults with CKD (stage 1-5 according to Kidney Disease Improving Global Outcomes (KDIGO) classification, 2024) and 150 healthy controls. CKD patients were further subdivided to 3 subgroups based on estimated glomerular filtration rate: stage 1-2, stage 3-4 and stage 5. BMD at the lumbar spine (LS), femur neck (FN), and distal radius (DR) were measured using DEXA. Vitamin D and OS biomarkers including; 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and Malondialdehyde (MDA) were measured. Paraoxonase1 (PON1) as a biomarker of antioxidant response was assessed. Statistical analysis was performed using the appropriate tests. RESULTS: The CKD cases showed lower BMD T-Scores than healthy controls. Moreover, LS, DR, and FN BMDs were significantly different between CKD stages. Post hoc analyses showed higher LS, DR, and FN T-Scores in Stage I-II vs. Stage III-IV and Stage V. However, no significant differences were noted between stage III-IV and stage V for all sites. Significant increase in OS biomarkers (8-OHdG and MDA) while decreasing antioxidant activity (PON-1) with CKD severity were observed. There was a significant positive correlation between PON1and BMD while 8-OHdG and MDA had a negative correlation with BMD. We also observed significant positive correlations between 8-OHdG and MDA with alkaline phosphatase and phosphorus, while these markers had significant negative correlations with vitamin D and calcium. PON1 had a significantly positive correlation with vitamin D & calcium. CONCLUSION: CKD patients suffer of OS. OS positively correlated with CKD severity. There is a negative relation between OS and BMD in CKD. OS might participate in the occurrence of OP in CKD.