Background. To date, hemodialysis (HD) is the most common therapy for chronic kidney disease (CKD) patients. However, it causes different complications such as sleep disorders. Sleep regulation is connected to vitamin D; hence, its deficiency might influence the quality and duration of sleep. This study is aimed at evaluating the correlation of sleep quality and vitamin D levels in 80 HD patients. Methods. This cross-sectional study was performed on 80 hemodialysis patients admitted to 29 Bahman hospitals in Tabriz, Iran. Before beginning of dialysis, serum 25 (OH) D levels were assessed among patients and the sleep patterns and sleep quality of patients were accurately calculated by the Pittsburgh sleep quality index (PSQI) standard questionnaire. Results. Our results showed that 22 HD patients (27.5%) had severe sleep disorders. In addition, it was found that serum levels of vitamin D had significant correlation with sleep quality (, ) in general, even after adjusting confounding factors such as calcium (Ca), phosphate (P), and parathyroid hormone (PTH) level. In poor sleepers (), a negative correlation was observed between the levels of vitamin D and PSQI score (, ). PSQI scores in the normal range of PTH (, ) and in >600 pg/ml of PTH (, ) had a correlation with vitamin D levels. The level of vitamin D was the single independent predictor of sleep efficiency (, ). Conclusion. The present project reported that the positive effect of vitamin D is associated with sleep disorder in HD patients. In future studies, normal levels of Ca and P should be considered along with normal vitamin D levels among the included patients.

中文翻译：

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血液透析患者睡眠质量与维生素 D 水平的关系

背景。迄今为止，血液透析（HD）是慢性肾脏病（CKD）患者最常见的治疗方法。但是，它会导致不同的并发症，例如睡眠障碍。睡眠调节与维生素 D 相关；因此，它的缺乏可能会影响睡眠的质量和持续时间。本研究旨在评估 80 名 HD 患者的睡眠质量与维生素 D 水平的相关性。方法。这项横断面研究是在伊朗大不里士的 29 家巴赫曼医院收治的 80 名血液透析患者中​​进行的。在透析开始前，对患者进行血清25（OH）D水平评估，并通过匹兹堡睡眠质量指数（PSQI）标准问卷准确计算患者的睡眠模式和睡眠质量。结果. 我们的结果显示，22 名 HD 患者 (27.5%) 有严重的睡眠障碍。此外，还发现血清维生素 D 水平与睡眠质量有显着相关性（, )通常，即使在调整了钙 (Ca)、磷酸盐 (P) 和甲状旁腺激素 (PTH) 水平等混杂因素后。在睡眠不佳的人中（），维生素D水平与PSQI评分呈负相关（, ）。PSQI评分在PTH正常范围内（, )和 >600 pg/ml PTH (, )与维生素 D 水平相关。维生素 D 水平是睡眠效率的唯一独立预测因子（, ）。 结论。本项目报道维生素 D 的积极作用与 HD 患者的睡眠障碍有关。在未来的研究中，应考虑纳入患者的正常水平的 Ca 和 P 以及正常的维生素 D 水平。