Comparisons of Serum Vitamin D Levels, Status, and Determinants in Populations With and Without Chronic Kidney Disease Not Requiring Renal Dialysis: A 24-Hour Urine Collection Population-Based Study

Objective: Vitamin D deficiency is frequent in the general population and might be even more prevalent among populations with kidney failure. We compared serum vitamin D levels, vitamin D insufficiency/deficiency status, and vitamin D level determinants in populations without chronic kidney disease (CKD) and with CKD not requiring renal dialysis. Design and Methods: This was a cross-sectional, multicenter, population-based study conducted from 2010 to 2011. Participants were from 10 centers that represent the geographical and cultural diversity of the Swiss adult population (>= 15 years old). Intervention: CKD was defined using estimated glomerular filtration rate and 24-hour albuminuria. Serum vitamin D was measured by liquid chromatography-tandem mass spectrometry. Statistical procedures adapted for survey data were used. Main Outcome Measure: We compared 25-hydroxy-vitamin D (25(OH) D) levels and the prevalence of vitamin D insufficiency/deficiency (serum 25(OH) D, 30 ng/mL) in participants with and without CKD. We tested the interaction of CKD status with 6 a priori defined attributes (age, sex, body mass index, walking activity, serum albumin-corrected calcium, and altitude) on serum vitamin D level or insufficiency/ deficiency status taking into account potential confounders. Results: Overall, 11.8% (135 of 1,145) participants had CKD. The 25(OH) D adjusted means (95% confidence interval [CI]) were 23.1 (22.6-23.7) and 23.5 (21.7-25.3) ng/mL in participants without and with CKD, respectively (P=.70). Vitamin D insufficiency or deficiency was frequent among participants without and with CKD (75.3% [95% CI 69.3-81.5] and 69.1 [95% CI 53.9-86.1], P=.054). CKD status did not interact with major determinants of vitamin D, including age, sex, BMI, walking minutes, serum albumin-corrected calcium, or altitude for its effect on vitamin D status or levels. Conclusion: Vitamin D concentration and insufficiency/deficiency status are similar in people with or without CKD not requiring renal dialysis. (C) 2014 by the National Kidney Foundation, Inc. All rights reserved.