维生素D缺乏与新冠是否有关? 当前,新冠肺炎已在世界范围内广泛传播。新冠病毒的大部分(80%–85%)感染者为无症状,其余为轻度或重度病例。轻度病例表现为非特异性症状,通常包括发烧,咳嗽,疲劳,腹泻,头痛和喉咙痛。无症状或轻度的病症通常会影响年轻人,而老年人则更容易出现严重症状,如急性呼吸道感染。新型冠状病毒的罪魁祸首虽尚未定论,但在 Journal Of Medical Virology 期刊中,来自美国Tulane大学Emad Kandil与Juan Duchesne团队的一篇文章“ Vitamin D insufficiency as a potential culprit in critical COVID‐\19 patients ”,对于维生素D缺乏症的患者与新冠患者的相关性进行了深入研究。研究表明,维生素D缺乏症(一种影响老年人、肥胖者、肤色较深的人或阳光照射不足的人的常见疾病)会成为急性呼吸道感染的风险因素。 在文章中,通过对总计1368名新冠阳性患者的数据分析得出结论,维生素D水平低(即缺乏)与患者病症及预后更加严重显著相关。维生素D缺乏不受年龄、性别或共病等“混杂因素”的影响,在疾病严重程度的表现中起着独立的致病作用。维生素D参与人体多种免疫反应:维生素D及其受体在先天和适应性免疫系统中均发挥作用,并减轻体内的抗微生物和抗炎过程。鉴于分子水平上的认识,作者推断维生素D缺乏症患者会增加出现更严重的病症或更糟糕的预后的风险。 另一项分析也表明,在每天补充维生素D的情况下,预防急性呼吸道感染的效果显著;该效果在维生素D缺乏的患者中表现更为明显。 鉴于维生素D通常是安全、价格低廉且较容易获得的药物,采取及时预防和治疗的措施可以减轻高危人群的严重病症 。 引用本文 : Munshi, R,Hussein, MH,Toraih, EA, et al.Vitamin D insufficiency as a potential culprit in critical COVID‐\19 patients. J Med Virol. 2020;1‐\8.https://doi.org/10.1002/jmv.26360 原文链接: https://onlinelibrary.wiley.com/doi/full/10.1002/jmv.26360 期刊简介: Journal of Medical Virology 出版有关影响人类健康对病毒领域的基础研究和应用研究的原创性论文。发表的文章涉及描述人体病毒感染的特征、诊断、流行病学、免疫学和发病机制的报告,以及有关病毒形态、遗传学、复制及与宿主细胞相互作用的基础研究。
维生素 D 缺乏可能会增加患 COVID-19 的风险 诸平 据美国芝加哥大学医学中心( University of Chicago Medical Center )格雷琴 · 鲁宾( Gretchen Rubin ) 2020 年 9 月 3 日提供的信息,在对接受 COVID-19 测试的患者的回顾性研究中,芝加哥大学医学院 ( University of Chicago Medicine , UChicago Medicine ) 的研究人员发现维生素 D 缺乏与被冠状病毒感染的可能性之间存在关联。 芝加哥大学医学院医院医学主任( Chief of Hospital Medicine at UChicago Medicine ),也是此项研究的领导作者大卫·梅尔泽( David Meltzer )博士说: “ 维生素 D 对免疫系统的功能很重要,维生素 D 补充剂先前已被证明可以降低病毒性呼吸道感染的风险。我们的统计分析表明,这对于 COVID-19 感染可能是正确的。 ” 研究团队对芝加哥大学医学院( UChicago Medicine )的 489 名患者进行了检查,这些患者的维生素 D 水平在接受 COVID-19 测试之前的一年内进行了测量。与维生素水平足够的患者相比,未经治疗的维生素 D 缺乏症( 20 ng / mL )的患者, COVID-19 冠状病毒检测阳性的可能性几乎是其两倍。 这项名为 “ 维生素 D 状态和其他临床特征与 COVID-19 测试结果的关联( Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results ) ” 的研究于 2020 年 9 月 3 日在《美国医学会杂志网络开放版》( JAMA Network Open )发表—— David O. Meltzer, Thomas J. Best, Hui Zhang, Tamara Vokes, Vineet Arora, Julian Solway. Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results . JAMA Network Open , 2020; 3 (9): e2019722 DOI: 10.1001/jamanetworkopen.2020.19722 。 meltzer_2020_oi_200688_1598473478.89934.pdf 在此之前已经在健康科学的预印服务器( medRxiv )上报告了其发现结果。 一半的美国人缺乏维生素 D ,非裔美国人、西班牙裔人和居住在芝加哥等地区的人,缺乏维生素 D 的比例更高,是因为芝加哥冬天很难获得足够的阳光照射。 大卫·梅尔泽说: “ 了解治疗维生素 D 缺乏症是否会改变 COVID-19 风险,不仅在当地,而且在全美国国和全球都具有重要意义。 ”“ 维生素 D 价格便宜,通常服用非常安全,并且可以广泛使用。 ” 大卫·梅尔泽和他的团队强调了进行实验研究的重要性,以确定补充维生素 D 是否可以降低 COVID-19 的风险以及潜在的严重性。他们还强调需要研究哪些维生素 D 补充策略在特定人群中最合适。他们已经在 UChicago Medicine 并与当地合作伙伴开展了多项临床试验。更多信息请注意浏览原文或者相关报道。 原文: meltzer_2020_oi_200688_1598473478.89934.pdf
维生素D水平低与能形成瘢痕的肺病相关 约翰•霍普金斯大学的研究人员研究了在10年内收集的6000多名成年人的医疗信息,并且发现血液中维生素D含量低于正常水平与早期间质性肺病(ILD)的风险增加相关。 间质性肺病(ILD)是一类相对罕见的疾病,其特征是肺部瘢痕和炎症,而这些可能会造成进行性,失能性和不可逆的肺损伤。在美国,估计每年大约有20万个确诊的病例,其中大多数是由环境毒素如石棉或煤尘造成的,但也可能是由自身免疫性疾病、感染、药物副作用或其它未知的原因引起的。 一旦确诊患有该病,大多数人的生存期不会超过5年。 在一系列研究中,研究人员试图了解与由计算机断层扫描(CT)发现的该疾病的早期征兆(可能在症状出现之前很久就存在影像异常)有关的、新的、可治疗的因素,这可能有助于指导未来对该病的预防策略。 最新的数据分析结果发表在2018年6月19日的《营养学杂志》( Journal of Nutrition )上。该结果显示维生素D水平低可能是发展出间质性肺病的一个因素。 虽然研究人员警告说研究结果不能证明它们之间存在因果关系,但该研究数据支持今后的研究需要调查维生素D缺乏症的治疗(例如补充剂或日光照射)是否可以帮助那些有该疾病风险的人预防或减缓疾病的进展。 目前,对确诊患上间质性肺病的患者而言,没有任何经过验证的治疗或者治愈该病的方法。 约翰•霍普金斯大学医学院医学副教授,约翰•霍普金斯Ciccarone心血管疾病预防中心预防心脏病学副主任 Erin Michos, M.D., M.H.S. ,表示 “我们知道激活的维生素D激素具有抗炎特性,并有助于调节免疫系统,而免疫系统会因ILD而出问题。文献中也有证据表明,维生素D在阻塞性肺病(如哮喘和COPD)中发挥作用,而我们现在发现这种关联也存在于这种会形成瘢痕的肺病中。” 为了寻找这种关联,Michos和她的研究团队使用了来自多种族动脉粥样硬化研究(MESA)的数据。该研究从2000年到2002年招募了6,814人, 参与者的平均年龄是62岁,53%是女性。 38%的参与者是白人,28%是非洲裔美国人,22%是西班牙裔,12%是华裔。 在首次临床就诊时,工作人员抽取了每个参与者的血液样本,并测量了维生素D的水平等。 那些维生素D水平低于每毫升20纳克 (约20%的参与者)被认为是维生素D不足(2,051人), 那些维生素D水平为每毫升20-30纳克的人被认为具有“中等”而不是最佳的水平,而那些每毫升含量为30纳克或更高的人被认为已达到推荐的水平。 所有受试者在首次就诊时接受了心脏CT扫描,有些患者在随后的随访中还提供了附带的或部分的肺部图像。 在10年的时间里,2,668名受试者进行了全面的肺部CT扫描,并由放射科医师评估是否存在瘢痕组织或其他异常情况。 与具有足够维生素D水平的受试者相比,缺乏维生素D的受试者的肺部亮点(受损肺组织)的平均体积更大(约2.7 cm 3 )。 这些差异是在调整了肺部疾病的年龄和生活方式风险因素(包括目前吸烟状况,吸烟年数,缺乏身体活动或肥胖等)之后得出的。 研究人员在考察全肺扫描的数据时表示,与具有最佳维生素D水平的参与者相比,那些维生素D水平不足或仅中等水平的参与者在其全肺扫描中发现异常(间质性肺病的早期征兆)的可能性要高50%至60%。 “我们的研究表明,足够水平的维生素D可能对肺部健康很重要。 我们现在可能需要考虑将维生素D缺乏症添加到该疾病过程相关因素的列表中,该列表中包括已知的ILD风险因素,例如环境毒素和吸烟等。” Michos进一步说, “但是,还需要更多的研究来确定优化血液维生素D水平是否可以预防或减缓这种肺部疾病的恶化。” 人们可以通过在夏季阳光下每天花15分钟晒太阳或通过食用脂肪含量高的鱼或强化奶制品来提高其维生素D水平。 一些有严重缺乏症的人可能需要考虑补养品。 据2013年全球疾病负担研究报告,全球每年约有595,000人患上间质性肺病,而且每年约有 491,000人死于此病。更多信息请访问 www.hopkinsmedicine.org. https://www.hopkinsmedicine.org/news/media/releases/low_vitamin_d_levels_associated_with_scarring_lung_disease Low Vitamin D Levels Associated with Scarring Lung Disease Release Date: June 19, 2018 Share Fast Facts Vitamin D may be protective for the lungs. - Click to Tweet Investigating preventable risk factors for deadly lung disease. - Click to Tweet Credit: iStock Reviewing medical information gathered on more than 6,000 adults over a 10-year period, Johns Hopkins researchers have found that lower than normal blood levels of vitamin D were linked to increased risk of early signs of interstitial lung disease (ILD). Interstitial lung disease is a relatively rare group of disorders characterized by lung scarring and inflammation that may lead to progressive, disabling and irreversible lung damage. An estimated 200,000 cases a year are diagnosed in the United States, most of them caused by environmental toxins such as asbestos or coal dust, but it can be caused by autoimmune disorders, infections, medication side effects or, sometimes, from unknown causes. Once diagnosed with the disease, most people don’t live longer than five years. In a series of studies, the researchers sought to learn about new, and potentially treatable, factors related to early signs of the disease seen by CT scans — imaging abnormalities that may be present long before symptoms develop — which may help guide future preventive strategies. Results of the most recent data analysis, published in the Journal of Nutrition on June 19, suggest that low vitamin D might be one factor involved in developing interstitial lung disease. Although the researchers caution their results can’t prove a cause and effect, their data support the need for future studies to investigate whether treatment of vitamin D deficiency, such as with supplements or sunlight exposure, could potentially prevent or slow the progression of the disorder in those at risk. Currently, there is no proven treatment or cure once interstitial lung disease is established. “We knew that the activated vitamin D hormone has anti-inflammatory properties and helps regulate the immune system, which goes awry in ILD,” says Erin Michos, M.D., M.H.S. , associate professor of medicine at the Johns Hopkins University School of Medicine and associate director of preventive cardiology at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease. “There was also evidence in the literature that vitamin D plays a role in obstructive lung diseases such as asthma and COPD, and we now found that the association exists with this scarring form of lung disease too.” To search for that association, Michos and her research team used data from the Multi-Ethnic Study of Atherosclerosis (MESA), which from 2000 to 2002 recruited 6,814 people from Forsyth County, North Carolina; New York City; Baltimore, Maryland; St. Paul, Minnesota; Chicago, Illinois; and Los Angeles, California. The average age of participants was 62, and 53 percent were women. Thirty-eight percent of participants were white, 28 percent were African-American, 22 percent were Hispanic and 12 percent were Chinese. At an initial clinical visit, staff took blood samples for each participant and measured, among other things, vitamin D levels. Those with vitamin D levels less than 20 nanograms per milliliter — about 30 percent of participants — were considered vitamin D deficient (2,051 people). Those with vitamin D levels of 20–30 nanograms per milliliter were considered to have “intermediate,” although not optimal, levels of the nutrient, while those with 30 nanograms per milliliter or more were considered to have met recommended levels. All participants underwent heart CT scans at the first visit and some also at later visits, offering incidental and partial views of the lungs. At 10 years in, 2,668 participants had full lung CT scans evaluated by a radiologist for presence of scar tissue or other abnormalities. The vitamin D-deficient participants had a larger volume, on average (about 2.7 centimeters cubed), of bright spots in the lung suggestive of damaged lung tissue, compared with those with adequate vitamin D levels. These differences were seen after adjusting for age and lifestyle risk factors of lung disease including current smoking status, pack years of smoking, physical inactivity or obesity. When looking at the data from the full lung scans, the researchers said those with deficient or intermediate vitamin D levels were also 50 to 60 percent more likely to have abnormalities on their full lung scans suggestive of early signs of interstitial lung disease, compared with those with optimal vitamin D levels. These associations were still seen after additionally adjusting for other cardiovascular and inflammatory risk factors, such as high blood pressure, high cholesterol, diabetes and levels of high-sensitivity C-reactive protein (another inflammatory marker). “Our study suggests that adequate levels of vitamin D may be important for lung health. We might now consider adding vitamin D deficiency to the list of factors involved in disease processes, along with the known ILD risk factors such as environmental toxins and smoking,” says Michos. “However, more research is needed to determine whether optimizing blood vitamin D levels can prevent or slow progression of this lung disease.” People can boost their vitamin D levels by spending 15 minutes a day in summer sunlight or through a diet that includes fatty fish and fortified dairy products. Supplements may be considered for some people with significant deficiency. According to the 2013 Global Burden of Disease study, about 595,000 people worldwide develop interstitial lung disease each year, and about 491,000 die each year from it. Additional authors include Samuel Kim, Di Zhao and Eliseo Guallar of Johns Hopkins; Anna Podolanczuk, R. Graham Barr and David Lederer of Columbia University Medical Center; Pamela Lutsey of University of Minnesota, Minneapolis; Steven Kawut of University of Pennsylvania; and Ian de Boer and Bryan Kestenbaum of University of Washington. The study was funded by grants from the National Institute on Neurological Disorders and Stroke (R01NS072243), the National Heart, Lung, and Blood Institute (R01HL096875, R01HL077612, R01HL093081, RC1HL100543, R01HL103676, T32HL105323 and K24HL131937) and the National Center for Advancing Translational Sciences (UL1TR000040, UL1TR001079 and UL1TR001420), as well as contracts from the National Heart, Lung, and Blood Institute (HHSN2682015400003I, N01HC95159, N01HC95160, N01HC95161, N01HC95162, N01HC95163, N01HC95164, N01HC95165, N01HC95166, N01HC95167, N01HC95168 and N01HC95169), funds from the Blumenthal Scholars Fund for Preventive Cardiology and a research assistance agreement from the U.S. Environmental Protection Agency (RD831697). Michos received an honorarium from Siemens Healthcare Diagnostics in 2016; de Boer has consulted for Medtronic and received equipment and supplies from Abbott for work outside this study. Lederer has consulted for Roche, Veracyte, Philips Respironics, FibroGen, Global Blood Therapeutics, Sanofi Genzyme and ImmuneWorks. Related Stories: Exercise and Vitamin D Better Together for Heart Health How Does Vitamin D Affect Women’s Health? Taking Vitamin D May Benefit People with Multiple Sclerosis Vitamin D Status Linked to Weight-Loss Surgery Outcomes
几年前,我的家庭医生在我的常规验血单中,加了一项维生素 D3 。结果显示我 D3 偏低。檀香山是一个阳光灿烂的城市。但是,我是宅女,每天在太阳下的时间应该不到 15 分钟。可能因为这个原因 (加上年龄大了,皮肤吸收阳光制造维生素 D 功能减弱),我需要补充维生素 D 。 医生让我每天口服维生素 D3 (大概是 2000 IU )。 6 个月后再检查,明显有效果。后来,我没有继续口服 D3 ,血液中的 D3 又掉下去了。现在我会常常服用 D3 。 我与一些在美国的中国朋友聊天,他们也有类似的经历:缺 D3 。 今天看到有关维生素 D 的报道,粗粗翻译其中的一部分,跟大家分享。 https://www.npr.org/sections/health-shots/2018/06/14/619896924/does-vitamin-d-really-protect-against-colorectal-cancer Does Vitamin D Really Protect Against Colorectal Cancer? 维生素D真的可以预防结直肠癌吗? June 14, 20181:31 PM ET Patti Neighmond It's been clear for many years that vitamin D helps keep bones strong, but studies have been inconclusive and conflicting about the vitamin's value in protecting against certain cancers, including colorectal cancer . 多年来,我们一直很清楚维生素D有助于保持骨骼健壮。但是,关于维生素能否预防某些癌症(包括结肠直肠癌),研究结果不能定论,还有些结果互相冲突。 Now a large international study provides the strongest evidence yet that vitamin D may indeed be protective against colorectal cancer and that a deficiency may increase the risk of this cancer. The findings appear Thursday in the Journal of the National Cancer Institute . 现在一项大型国际研究提供了最有力的证据,表明维生素D确实可以预防结肠直肠癌,并且指出维生素D缺乏症可能会增加结肠直肠癌的风险。这些结果发表在周四的《美国国家癌症研究所杂志》上。 … Another interesting observation in the study, McCullough says, was that beyond a certain level, increasingly higher amounts of vitamin D in the blood had no effect: Levels of the vitamin that were higher than what is considered adequate were not associated with an even smaller risk. In other words, she says, more is not necessarily better. McCullough说,这项研究中另一个有趣的观察结果是如果血液中维生素D超过一定的水平,越来越高的维生素D含量(对癌症风险)没有影响。也就是说,维生素水平高于被认为“足够的水平“时,不会导致(癌症)风险减小。换句话说,“更多(维生素D)不一定更好。” Her take-home message: Don't race out and buy high doses of vitamin D just in case. Overdoing it can be toxic. Taking too much vitamin D can cause kidney stones and, in very rare cases, death. 她让读者记住:不要为了“以防万一”而立马去购买高剂量的维生素D。过度摄入维生素D可能伤害身体。服用过多的维生素D会导致肾结石,并且在极少数情况下会导致死亡。 The issue of whether vitamin D supplements should be used at all to prevent colorectal cancer is still up in the air. The key question now is whether intervening with people who have low levels of vitamin D can make a difference, says Dr. Jeffrey Meyerhardt , director of the Gastrointestinal Cancer Center at Dana-Farber Cancer Institute in Boston, who was not involved in the study. 是否应该用补充维生素D来预防结直肠癌的问题仍然悬而未决。波士顿Dana-Farber癌症研究所胃肠道癌症中心主任JeffreyMeyerhardt博士(不是该论文作者)说:“现在关键的问题是,干预维生素D水平低的人,是否可以产生影响(即减少癌症)?” … In the meantime, he suggests people talk with their health care provider about having a blood test to measure vitamin D levels. If you're starting in the deficient range, he says, some doctors might prescribe high doses, to be taken each week ( Zuojun’s note: should be each day? ) for a month or two, and then prescribe lower, maintenance levels. 与此同时,他建议人们与他们的医疗保健提供者(注:一般就是医生)谈论进行血液检测,以测量维生素D水平。他说,如果你缺少维生素D,一些医生可能会开大剂量,服用1-2个月,然后转用较低的剂量,以便维持维生素D水平。 The cancer society's McCullough says it is generally recommended that adults have a daily intake of 600 international units of vitamin D up to age 70. Men and women over age 70 should increase their uptake to 800 IUs daily, she says. 癌症协会的McCullough说,通常建议成年人每天摄入600国际单位的维生素D,一直至70岁。她还说:70岁以上的男性和女性每天应摄入800国际单位的维生素D。 People should talk with their doctor because different individuals have different needs, she says. 她说:大家应该与医生交谈,因为不同的人有不同的(维生素D)需求。 It depends on where you live and what race you are, because darker skin tends to absorb less vitamin D. Sun, age, genetics and weight also play a role in how the body processes vitamin D. “这取决于你住在哪里以及你是什么种族,因为较深的皮肤往往会吸收较少的维生素D.”太阳、年龄、遗传和体重也会影响身体中的维生素D水平。 Vitamin D can be obtained from vitamin D-rich foods such as egg yolks, salmon, trout, swordfish, tuna and sardines. Numerous foods are fortified with vitamin D including cow's milk, almond milk, soy milk, some cereals and some orange juices. 维生素D可以从含有维生素D丰富的食物,如蛋黄、三文鱼、鳟鱼、箭鱼、金枪鱼和沙丁鱼获得。许多食物都含有维生素D,包括牛奶、杏仁奶、豆奶、一些谷类食物和一些橙汁。(注:美国的牛奶一般加D。) If you have a serving of salmon, that's about 500 IUs, and a cup of milk would give you 100 IUs, McCullough says, which adds up to the daily recommended dose of 600 IUs. McCullough说:“如果你吃一份三文鱼,约摄入500国际单位的维生素D。一杯牛奶会给你100国际单位的维生素D。”这加起来就是600国际单位,即每天推荐剂量。 But Meyerhardt says most people don't eat enough fatty fish to reach the recommended vitamin D intake. 但Meyerhardt说,大多数人不会吃足够的含高脂肪的鱼,所以达不到推荐的维生素D摄入量。 Most vitamin D doesn't really come from your diet in most cases, he says. And he says multivitamins contain relatively low levels of vitamin D. So you really have to take a supplement to meet recommended doses. 他说,大多数情况下,大多数维生素D并不是真的来自你的饮食。他说,多种维生素含有相对较低水平的维生素D。“所以你真的不得不服用保健品”以达到推荐的维生素D剂量。 Vitamin D is often called the sunshine vitamin, because exposure to sunlight can stimulate production of the vitamin. But exposure to sun is generally not recommended as a way to boost vitamin D, McCullough says, since at excessive levels it can raise the risk of melanoma and other skin cancers. 维生素D通常被称为“阳光”维生素,因为暴露在阳光下可以刺激维生素的产生。但医生一般不建议将太阳光照射作为促进维生素D的一种方式。McCullough说,因为阳光照射水平过高会增加黑素瘤和其他皮肤癌的风险。 More than 20 medical centers and organizations participated in the study, including Harvard, the American Cancer Society and the National Cancer Institute. 超过20个医疗中心和组织参与了这项研究,包括哈佛大学、美国癌症协会和国家癌症研究所。
维生素 D 水平与中国老年人大脑衰退之风险 诸平 《老年医学杂志 A 辑:生物科学与医学》( The Journals of Gerontology Series A: Biological Sciences and Medical Sciences ) 2016 年 7 月 12 日发表了新加坡、美国、日本以及中国作者联合撰写的一篇论文,阐述了维生素 D 水平与中国老年人大脑认知能力衰退风险之间的关系。 2016 年 7 月 27 日 , MedicalXpress 网站对此进行了简要介绍。此项研究成果是由杜克 - 新加坡国立大学医学院( Duke-NUS Medical School )、美国杜克大学医学院( Duke University Schoolof Medicine )、日本筑波大学医学院( Faculty of Medicine, University of Tsukuba )、中国疾病防控中心( Chinese Center for Disease Control and Prevention )、北京大学 Raissun 高级研究所( Raissun Institute for Advanced Studies, Peking University )的研究人员合作完成的 。 维生素 D(vitamin D , VD) 是固醇类的衍生物,具有抗佝偻病作用,故又被称抗佝偻病维生素。 目前认为维生素 D 也是一种类固醇 激素 ,维生素 D 家族成员中最重要的成员是 VD2( 麦角钙化醇 ) 和 VD3( 胆钙化醇 ) 。维生素 D 均为不同的维生素 D 原经紫外照射后的 衍生物 。植物不含维生素 D ,但维生素 D 源在动、植物体内都存在。维生素 D 是一种 脂溶性维生素 ,有 5 种 化合物 ,对健康关系较密切的是 维生素 D2 和维生素 D3 。它们有以下三点特性即存在于部分天然食物中 ; 人体皮下储存有从胆固醇生成的 7- 脱氢胆固醇,受紫外线的照射后可转变为维生素 D3 。因此适当的日光浴足以满足人体对维生素 D 的需要。但是新加坡、美国、日本以及中国的研究人员联合研究发现,中国老年人当中维生素 D 水平低的,随后患认知能力下降的风险和认知能力障碍会增加。 由于维生素 D 对于维持健康的骨骼和肌肉是必要的。维生素 D 缺乏会导致少儿佝偻病和成年人的软骨病。佝偻病多发于婴幼儿,主要表现为神经精神症状和骨骼的变化。神经精神症状上表现为多汗、夜惊、易激惹。骨骼的变化随年龄、生长速率及维生素 D 缺乏的程度等因素有关。可出现卢骨软化、肋骨串珠等。骨软化症多发生于成人,多见于妊娠多产的妇女及体弱多病的老人。最常见的症状是骨痛、肌无力和骨压痛。症状包括骨头和 关节 疼痛、 肌肉萎缩 、失眠、 紧张 以及痢疾腹泻。维生素 D 主要用于组成和维持 骨骼 的强壮。它被用来防治儿童的佝偻病和成人的 软骨症 ,关节痛等等。患有骨质疏松症的人通过添加合适的维生素 D 和镁可以有效的提高钙离子的吸收度。除此以外,维生素 D 还被用于降低结肠癌、乳腺癌和前列腺癌的机率,对免疫系统也有增强作用。 维生素 D 的前体也就是生成维生素 D 的原料存在于皮肤中,当阳光直射时会发生反应转化为维生素 D3(VD3) , VD3 分子被运送到肝脏并且转化为维生素 D 的另一种形式 25 位单脱氧 胆固醇 ,这种形式的效用更大。然后 25 位单脱氧胆固醇又被转运到肾形矿脉并在那里被转化为 1 , 25 位二羟胆钙化 ( 甾 ) 醇,这种形式是维生素 D 最有效的状态。然后维生素 D 将和 甲状旁腺激素 以及降血钙素协同作用来平衡血液中钙离子和磷的含量,特别是增强人体对钙离子的吸收能力。维生素 D 不宜用于血钙过高的病人,或者血液中钙离子含量偏高的人。另外对患有肾结石和动脉硬化的病人来说也必须小心使用,因为维生素 D 可能会引起他们的 甲状旁腺疾病 ,削弱 肾功能 甚至引起心脏疾病。除此之外, 据相关信息报道维生素 D 在维持健康的大脑功能方面也扮演了一个重要的角色。已有研究结果显示,那些维生素 D 水平较低的人,心血管和神经退行性疾病的风险会增加 , 而来自欧洲和北美的研究结果显示,维生素 D 水平低的人与未来认知能力的下降有关。 新加坡、美国、日本以及中国的研究人员合作进行的最新研究结果,是以中国老人为研究对象,随访了 1202 名年龄在 60 岁或者以上的、认知完整的中国老年人,随访持续时间为 2 年。采用简易智能测量表( Mini-Mental State Examination , MMSE) 来评价参与者的认知状态。认为当 MMSE 评价得分低于 18 时即为认知障碍;当 MMSE 评价得分偏离基线 ≥3 时就认为是认知衰退。多变量逻辑回归模型被用来研究维生素 D 水平和认知能力下降和认知障碍的发生率之间的相关性。这也是首次大规模在亚洲进行的一项前瞻性研究,即研究维生素 D 状态与中国老年人认知衰退的风险和障碍之间的相关性。 无论性别和老年化程度 , 在此项研究开始之前维生素 D 水平较低的个体,认知能力表现出显著下降人数大约是维生素 D 水平正常的个体的两倍。此外 , 维生素 D 水平基线较低的个体,未来认知障碍的风险也会增加 2~3 倍。 Duke-NUS 医学院健康服务和系统研究项目主任( Director of theHealth Services and Systems Research Programme at Duke-NUS Medical School ),也是该研究论文的第一作者戴维·马沙尔( David Matchar )教授说: “ 虽然此研究对象来自中国 , 但是其研究结果适用于亚洲地区 , 因为其大部分老年人还是华人 , 如新加坡就是一个例证。 ” 这些发现强化了这样一个观念即维生素 D 可以预防神经元损伤和减少 , 并呼吁更密集的调查来研究补充维生素 D 对认知能力下降的影响。更好的理解维生素 D 能保护神经元,可能有助于认识随着人口老龄化的到来,阻止 认知能力下降 患病率的迅速增加,有效干预措施的机制。更多信息请浏览原文。 David B. Matchar , Choy-Lye Chei , Zhao-Xue Yin , Victoria Koh , Bibhas Chakraborty , Xiao-Ming Shi , Yi Zeng . Vitamin D Levels and the Risk of Cognitive Decline in Chinese Elderly People: the Chinese Longitudinal Healthy Longevity Survey . The Journals of Gerontology Series A: Biological Sciences and Medical Sciences , 2016, doi: 10.1093/gerona/glw128 . First published online: July 12, 2016 Abstract Background : Vitamin D has a neuroprotective function, potentially important for the prevention of cognitive decline. Prospective studies from Western countries support an association between lower vitamin D level and future cognitive decline in elderly people. No prospective study has examined this association in Asia. Methods: This community-based cohort study of elderly people in China follows 1,202 cognitively intact adults aged ≥60 years for a mean duration of 2 years. Plasma vitamin D level was measured at the baseline. Cognitive state ofparticipants was assessed using the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as an MMSE score 18. Cognitive decline wasdefined as ≥3 points decline from baseline. Multivariable logistic regression models were used to examine the association between quartiles of vitamin D levels with cognitive decline and incidence of cognitive impairment. Results: Participants with low vitamin D level had an increased risk ofcognitive decline. Compared with the highest quartile of vitamin D levels, themultivariable odds ratios (ORs; 95% confidence interval) for cognitive declinewere 2.1 (1.3–3.4) for the second highest quartile, 2.2 (1.4–3.6) for the thirdhighest quartile, and 2.0 (1.2–3.3) for the lowest quartile. The multivariable ORs of incident cognitive impairment for the second highest, third highest, andlowest versus highest quartiles of vitamin D levels were 1.9 (0.9–4.1), 2.6(1.2–5.6), and 3.2 (1.5–6.6), respectively. Conclusions: This first follow-up study of elderly people, including theoldest-old, in Asia shows that low vitamin D levels were associated withincreased risk of subsequent cognitive decline and impairment.