Association between Serum Vitamin D Levels and Sleep Disturbance in Hemodialysis Patients

Sleep disturbance is a frequent and serious complication of hemodialysis (HD). Low serum vitamin D levels have been associated with sleep quality in non-HD subjects. Our aim was to examine the possible association between serum vitamin D levels and the presence of sleep disturbance in HD patients. We recruited 141 HD patients at the HD center of the First Affiliated Hospital of Jiaxing University during 2014-2015. Serum levels of 25-hydroxyvitamin D (25(OH) D) were determined by the competitive protein-binding assay. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI). Demographic, clinical and laboratory data were recorded. Meanwhile, 117 healthy control subjects were also recruited and underwent measurement of 25(OH) D. Eighty-eight patients (62.4%) had sleep disturbance (PSQI scores >= 5). Patients with sleep disturbance showed lower levels of 25(OH) D as compared to those without sleep disturbance (85.6 +/- 37.4 vs. 39.1 +/- 29.1 nmol/L, p < 0.001). In multivariate analyses, serum levels of 25(OH) D (<= 48.0 nmol/L) were independently associated with sleep disturbance in HD patients (OR 9.897, 95% CI 3.356-29.187, p < 0.001) after adjustment for possible variables. Our study demonstrates that low serum levels of vitamin D are independently associated with sleep disturbance in HD patients, but the finding needs to be confirmed in future experimental and clinical studies.