Risk Factors for Vitamin D Deficiency in Patients with Chronic Kidney Disease

OBJECTIVE: We conducted a cohort study to identify the risk factors for vitamin D deficiency in predialyzed patients with chronic kidney disease (CKD). METHODS: An observational study of 135 outpatients with stage 3-5 CKD was undertaken. Clinical and biochemical parameters were analyzed in terms of nutritional status, inflammation, and mineral metabolism in relation to serum levels of 25-hydroxyvitamin D [25(OH)D]. Levels of 25(OH)D lower than 15 ng/mL were considered to be deficient. RESULTS: The 25(OH)D-deficient group had a higher body mass index (24.1±4.2 kg/m(2) vs. 22.5±4.0 kg/m(2), p=0.0322), and had more diabetic patients (27.9% vs. 3.6%, p=0.0003). The multivariate analysis revealed that body mass index (odds ratio=2.758; 95% CI, 1.048-7.721; p=0.0398), the presence of diabetes (odds ratio=7.792; 95% CI, 1.808-55.439; p=0.0043), lower hemoglobin concentration (odds ratio=0.297; 95% CI, 0.099-8.732; p=0.821), higher serum levels of non-HDL cholesterol (odds ratio=3.570; 95% CI, 1.449-9.442; p=0.0053) and triglyceride (odds ratio=2.447; 95% CI, 0.779-1.776; p=0.0258) were the factors associated with low 25(OH)D levels. CONCLUSION: Vitamin D deficiency was common among the predialysis CKD patients, and the factors identified as being associated with vitamin D deficiency were diabetes and obesity.