Risk Factors for Hypovitaminosis D in Nondialyzed Chronic Kidney Disease Patients

Abstract

Background: Hypovitaminosis D is highly prevalent among patients with chronic kidney disease and has been associated with worse outcome even in the earlier stages of the disease.Objective: This study aimed to investigate the risk factors for hypovitaminosis D in nondialyzed patients with chronic kidney disease.Design: This cross-sectional study included 120 patients with chronic kidney disease at stages 2 to 5 (62% male, age: 55.4 +/- 11.3 year, estimated glomerular filtration rate: 35.1 +/- 15 mL/minute, body mass index [BMI]: 27.1 +/- 5.2 kg/m(2), 31% diabetics). Serum 25-hydroxivitamin D [25(OH) D] was measured by chemiluminescence. Subjective global assessment, total body fat (dual-energy X-ray absorptiometry), visceral and subcutaneous abdominal fat (computed tomography), and several laboratory parameters were assessed.Results: Insufficiency of 25(OH) D (15 to 30 ng/mL) was observed in 55% and deficiency (<15 ng/mL) in 20% of the patients. Patients with diabetes, BMI >= 30 kg/m(2), and who had the blood collection during the winter or spring had lower levels of 25(OH) D. Serum 25(OH) D correlated inversely with parathyroid hormone, proteinuria, insulin resistance, leptin, and subcutaneous abdominal fat. the risk factors for hypovitaminosis D were diabetes (odds ratio: 3.8; 95% CI: 1.2 to 11.7; P = .022) and BMI >= 30 kg/m(2) (odds ratio: 4.3; 95% CI: 1.2 to 15.3; P = .018). in the logistic regression analysis adjusting for gender, skin color, and season of the year, diabetes and BMI >= 30 kg/m(2) were independently associated with hypovitaminosis D.Conclusions: Diabetes and obesity were the risk factors for hypovitaminosis D in nondialyzed patients with chronic kidney disease. Effective interventional protocols of vitamin D supplementation taking into account these risk factors are warranted for this population. (C) 2012 by the National Kidney Foundation, Inc. All rights reserved.