Page 5 Journal homepage: www.ijcbr.com INTERNATIONAL JOURNAL OF CLINICAL AND BIOMEDICAL RESEARCH ABSTRACT Background & Objective: Chronic Kidney Disease (CKD) is emerging as an important public health problem across the world. In severe cases, the disease progresses towards end stage renal disease (ESRD) which is associated with several complications. In recent years, 25 (OH) Vitamin D has been identified as a risk factor for ESRD. Vitamin D plays a vital role in regulating parathyroid hormone (PTH) synthesis and release. Decreased Vitamin D levels are identified as a risk factor for secondary hyperparathyroidism (SHPT) which is one of the major complications of CKD and is associated with renal osteodystrophy. The present study was planned to assess the status of 25 (OH) Vitamin D and its role in secondary hyperparathyroidism in patients with CKD. Materials and Methods: The study was conducted on 50 diagnosed cases of CKD (stage 4 and 5), age < 60 years. Age and sex matched healthy subjects (n = 50) constituted the control group. Serum 25(OH) Vitamin D and iPTH were estimated for all the enrolled subjects. BMI and eGFR were also calculated. All variables were compared among the control and diseased group. Results: Vitamin D levels were significantly low in the CKD group as compared to the control group (p<0.001). 72% of the total CKD patients were deficient in Vitamin D levels. Serum iPTH was significantly higher in the CKD patients (p = 0.000). A significant negative correlation was observed between iPTH and Vitamin D (r = -0.614).Conclusion: The study suggests that patients of CKD are at high risk of Vitamin D deficiency. Vitamin D deficiency has a strong association with the pathogenesis of SHPT. KEYWORDS: Chronic Kidney Disease, Vitamin D, Parathyroid hormone, Secondary Hyperparathyroidism, End Stage Renal Disease. INTRODUCTION In the last few decades, chronic kidney disease (CKD) has emerged as a global health problem of epidemic proportions. It has a major effect on healthcare costs and world productivity, particularly in developing countries where the young people are the most afflicted population. Although in many persons CKD remains an asymptomatic pathologic condition that progresses slowly. For many others, CKD represents a progressive irreversible process that ultimately requires renal replacement therapy. The burden of CKD includes not only progression to end-stage renal disease (ESRD), but also complications related to renal impairment and increased risk of cardiovascular diseases [1] . Cardiovascular disease events are the leading cause of morbidity and mortality in patients with CKD. Left ventricular hypertrophy and vascular calcification are more prevalent among patients with CKD. Additionally, hyperparathyroidism and hypovitaminosis D are independent risk factors for vascular calcification [2, 3] . With the growing global epidemic of traditional risk factors like hypertension and diabetes in particular, the prevalence of CKD and kidney failure is rising continuously [4, 5] . In the past ten years, the incidence and prevalence of end-stage renal disease have doubled and expected to continue to rise steadily in the future. In addition to the well-known risk factors; several nontraditional risk faĐtors ŵaLJ ĐoŶtriďute to the progressioŶ as well as higher risk of death in patients with CKD compared to the general population [1, 6-8] . The increased morbidity and mortality related to CKD may be reduced with early detection and effective management of risk factors to prevent or delay further progression of renal dysfunction and its associated complications. In recent years, vitamin D deficiency has been recognized as a prominent feature of CKD. Growing evidences suggest that progression of CKD and many of the secondary complications like disturbance in bone mineral metabolism, inflammation, cardiovascular disease, anemia and neuropathy may be linked to vitamin D [1, 3, 6-8] . In-vitro studies indicate that vitamin D besides maintaining bone mineral homeostasis, involved in a wide range of physiological functions, including regulation of Research article JAIPRAKASH YOGI 1, BUSHRA FIZA 1, SURAJ GODARA 2, MAHEEP SINHA 1 AUTHOR DETAILS Received: 2 nd Feb 2017 Revised: 19 th Feb2017 Accepted: 24 th Feb 2017 Author details: 1 Department of Biochemistry, Mahatma Gandhi Medical College & Hospital, Jaipur 2 Department of Nephrology, Mahatma Gandhi Medical College & Hospital, Jaipur Corresponding author: BushraFiza, Department of Biochemistry, Mahatma Gandhi Medical College & Hospital, RIICO Institutional Area, Sitapura, Jaipur, Rajasthan (India). Pin 302022 Email: bushrafiza786@gmail.com Int J Clin and Biomed Res. 2017;3(2): 05-09 Yogi et al., SERUM 25(OH) VITAMIN D AND ITS ROLE IN SECONDARY HYPERPARATHYROIDISM IN PATIENTS WITH CHRONIC KIDNEY DISEASE