嗜睡的人躺下不到5分钟就打起呼噜，甚至开车､吃饭､说话或在会议中都可以睡着｡
《临床睡眠医学杂志》刊登美国一项新研究发现，血液维生素D水平与白天嗜睡之间存在很强但是较为复杂的关联。
美国睡眠医学会完成的这项新研究对81名因为睡眠问题而上医院就诊的患者进行了研究。这些患者最终被确诊患有睡眠紊乱症。大多数患者罹患阻塞性睡眠呼吸暂停。该病患者在睡眠过程中会反复出现呼吸暂停。
研究人员测量了参试患者白天的嗜睡情况，同时还通过血检测量了参试者的维生素D水平。结果发现，在维生素D水平正常的参试患者中，维生素D水平与白天嗜睡之间成反比例关联。即，维生素D水平越低，白天就越容易犯困。但是在维生素D缺乏的患者中，这种关联只出现在黑人患者中。而在其他缺少维生素D的患者中，维生素D较高与白天犯困之间存在关联。
新研究负责人大卫·麦卡蒂博士表示，新研究发现，维生素D水平低与白天犯困之间存在重要关联。但是这种关联的复杂性又超乎研究人员最初的设想。这项研究有必要继续深入，以彻底理清维生素D与白天嗜睡之间的关系。
研究人员表示，这项新研究首次表明维生素D水平与嗜睡之间存在重要关联。这种关联受种族影响。皮肤较黑是维生素D水平偏低的一大已知风险因素。其原因是，晒太阳是人体产生维生素D的重要途径，因此维生素D又有“阳光维生素”之称。
麦卡蒂博士表示，新研究发现维生素D与白天易嗜睡之间存在重要关联，但目前还不能断言两者之间存在因果关系。相关研究尚待继续。
Vitamin D, Race, and Excessive Daytime Sleepiness
David E. McCarty, M.D.; Aronkumar Reddy, M.D.; Quinton Keigley, B.S.; Paul Y. Kim, Ph.D.; Andrew A. Marino, Ph.D.
Study Objectives First, to determine whether serum vitamin D levels were correlated with excessive daytime sleepiness (EDS) in patients with or without vitamin D deficiency (VitDd). Second, to assess whether race affected the relation between vitamin D levels and EDS.
Methods Serum 25-hydroxyvitamin D (25OHD) was measured by immunoassay in a consecutive series of 81 sleep clinic patients who complained of sleep problems and nonspecific pain (25OHD < 20 ng/mL ' VitDd). Sleepiness was determined using the Epworth Sleepiness Scale score ([ESSs] ESSs ≥ 10 ' EDS). Correlations were assessed using Pearson r.
Results In patients without VitDd (25OHD ≥ 20 ng/mL), ESSs was inversely correlated with vitamin D concentration (r = 0.45, p < 0.05). The group consisted of 6% black patients, compared with 35% for the entire cohort. Among the patients who had VitDd (25OHD < 20 ng/mL), ESSs was directly correlated with 25OHD in black (r = 0.48, p < 0.05) but not white patients. In black patients, mean ESSs in patients with VitDd were higher and 25OHD levels were lower p < 0.05).
Conclusions The results suggested the novel possibility that VitDd-related disease has a yet-to-be-identified mechanistic role in the presentation of sleepiness, sleep disorders, or both. Further research is needed to clarify the mechanism(s) involved in producing the complex relationships noted.
