维生素D的最新研究进展

维生素D(Vitamin D,VD)是调节骨代谢的重要维生素,婴幼儿及儿童缺乏VD会导致佝偻病,成人及老人缺乏VD会导致骨质疏松症。近期研究表明,VD与高血压、2型糖尿病、血脂紊乱、代谢综合征、过敏性疾病及哮喘、免疫调节和抗炎、抗纤维化、心血管疾病、结核病、慢性肾脏病、各种癌症、感染、甚至死亡等方面密切相关。随着我国老龄化社会的到来和现代生活水平的提高,人们对VD的缺乏越来越重视,因此VD缺乏的患者越来越少。相反,因过量服用VD后中毒的病例却时有发生。安全始终是首要考虑的因素,在中毒剂量范围内补充人体需要的VD,应做好VD摄入水平及VD中毒的健康宣教。外源性途径摄入VD的同时,增加户外活动时间,多进行日光照射产生内源性维生素。在VD缺乏的预防和治疗过程中,应注意掌握VD摄入量和用药周期,密切观察,定期随访,避免VD中毒事件的发生,以期达到降低维生素D缺乏及维生素D缺乏性佝偻病的发生。     

维生素D与老年骨质疏松

目前维生素D缺乏巳成为一个世界性问题。近年来许多研究观察到很多国家的居民存在不同程度的维生素D( VitD) 缺乏,而老年人群又因为饮食因素、户外活动减少、胃肠吸收减少、肾功能减退等因素,使其成为VitD缺乏的最高危人群。目 前研究结论多来自国外研究,需要在中国开展不同人群VitD及其相关因素疾病的深人研究。本文旨在讨论老年人VitD与骨 质疏松的关系,进一步为老年人骨质疏松的防治和骨的健康提供理论依据。     

维生素D与骨质疏松概述

作为营养尬发的维生素Ｄ在维持正常骨钙化,钙平衡及肠道钙吸收等方面起着十分重要的作用。然而维生素Ｄ本身并不是生物活性物质。维生素Ｄ经过肝脏及肾脏转化,形成其生物代谢活必平物－－１．２５（ＯＨ）２Ｄ３。１,２５（ＯＨ）２Ｄ３为甾体激素,其生物学效应由细胞核受体（ＶＤＲ）介导,在人体许多脏器包括肠道及骨组织发挥其生物学作用。在上述维生素Ｄ代谢系统中,任何环节发生异常均可导致人体疾病,包括骨质疏松（ＯＰ）     

骨质疏松症治疗中维生素D的最佳水平及补充剂量的研究进展

人们普遍认为维生素D(vitamin D,VD)是骨骼系统中的积极调节因子。近年来,骨质疏松症发病率的增加,VD不足及缺乏现象明显,国内外越来越多研究发现骨密度与VD状态之间存在不一致表现,高水平VD状态对提高骨密度及降低骨折风险并没有起到积极作用,VD最佳水平和在骨质疏松症治疗时如何补充VD仍有争议。笔者综述了近年来的研究成果,进一步探讨VD最佳水平、高水平VD的补充对骨密度及骨折的影响,并提出目标25-羟维生素D[25-hydroxyvitamin D,25(OH)D]浓度为20 ng/mL(50 nmol/L),每日VD补充剂量为400~800 IU,超过这一水平增加VD补充剂量是不必要的,甚至可能存在潜在危险。     

维生素D与骨折相关性

维生素D在体内主要与钙、磷代谢相关,作用于骨的生长发育和维护。维生素D缺乏导致骨质疏松,易引起骨折;骨折后维生素D调节钙、磷代谢,参与骨折修复,促进骨折愈合。骨折修复过程中会引起体内维生素D发生变化,补充维生素D对促进骨折愈合是否有益,尚有争议。全球范围内维生素D缺乏较为普遍,维生素D缺乏人群,尤其是老年人补充维生素D可提高骨密度,直接减少骨折发生;增加肌肉力量,预防跌倒,间接减少骨折发生。本文就维生素D与骨折相关性研究进展作一概述。     

维生素D与人体健康

讨论生命元素维生素D( VUD)与健康的关系,维生素D普遍缺乏。随着科学发展,对维生素D (VUD)及其活性形式——活性维生素D( AVD)在骨骼健康、心血管疾病、肿瘤、糖尿病、孕期保健、小 儿佝偻病等益处不断被发现。本文对其进行讨论,并附上我科近3年对活性维生素D( AVD)检测情 况的报告。     

上海地区中老年人维生素D与骨密度之间的相关性调查

目的研究维生素D与骨密度的相关性。方法调查248名自由居住在上海的中老年人,女性128名,男性120名,年龄在40到90之间,他们都是从人口基数中随机选入的。分别测量选入对象的全身骨密度和血清中25(OH)D的含量,分析两者之间的相关性。结果研究对象的平均年龄70.03±11.44岁,其中男性的平均年龄为70.96±12.22岁,女性的平均年龄为69.16±10.62岁。研究对象的平均25(OH)D的总量浓度为13.733±6.894 ng/ml;平均25(OH)D2的浓度为1.672±1.577 ng/ml,平均25(OH)D3的浓度为12.057±6.631 ng/ml。其中男性平均25(OH)D的总量浓度为14.258±5.557 ng/ml;平均25(OH)D2的浓度为1.580±1.548 ng/ml,平均25(OH)D3的浓度为12.710±5.440 ng/ml。女性平均25(OH)D的总量浓度为13.241±7.937 ng/ml;平均25(OH)D2的浓度为1.758±1.604 ng/ml,平均25(OH)D3的浓度为11.445±7.550 ng/ml。研究对象中97%(n=241)25(OH)D的浓度小于30 ng/ml;其中男性中99%的人(n=119)25(OH)D的浓度小于30 ng/ml;女性中95%的人(n=122)25(OH)D的浓度小于30 ng/ml。研究对象中83%(n=206)的人伴有股骨颈骨质疏松;86%的人(n=214)伴有腰椎的骨质疏松。其中男性中82%的人(n=98)伴有股骨颈骨质疏松,84.2%的人(n=101)伴有腰椎的骨质疏松。女性中84.4%的人(n=108)伴有股骨颈骨质疏松,88.3%的人(n=113)伴有腰椎的骨质疏松。在多变量的数据分析里,校正了年龄、体重指数的差异后,发现25(OH)D与骨密度之间存在一定关系(见表3、4、5)。结论在中国上海健康中老年人群中存在严重的维生素D不足和缺乏状况,维生素D的状态与骨密度可能存在正性相关,必须进一步进行大样本的研究来探讨维生素D与骨质疏松症及骨折的关系。     

维生素D缺乏对骨骼肌肉系统的影响

维生素D是人体不可缺少的一种脂溶性维生素,主要功能是促进肠道对钙、磷的吸收。维生 素D缺乏会引起继发性甲状旁腺功能亢进,骨转化加快,骨丢失增加,从而引起骨软化、骨质疏松、骨 折。另外维生素D缺乏与肌无力、活动能力下降相关,使患者跌倒发生率增加。科学有效的补充维 生素D,不但能够防止由于钙、磷吸收障碍所导致的骨质疏松及骨折的发生,还能有效防止多种骨骼 肌肉系统疾病。     

苏州市民维生素D现况研究

目的 了解苏州市民维生素D现况,为提高苏州市民骨健康提供基础数据.方法 随机选取7～96岁苏州市民301人,用Elisa试剂盒测定血清中25羟维生素D(25(OH)D3)水平.结果 112名男性和183名女性参加了检测,平均年龄59.97±19.08岁;99.3%的苏州市民维生素D缺乏,其中64.5%为严重缺乏;不同类型人员之间差异有显著性(χ2=67.096,P＜0.0001),不同性别(χ2=1.918,P=0.166)、不同年龄(χ2=6.792,P=0.340)间差异无统计学意义.结论 苏州市民普遍存在维生素D缺乏,如果不及时采取措施,将导致严重的骨健康问题.人群中长期严重缺乏维生素D对骨代谢产生的副作用值得进一步跟踪研究.     

维生素D受体等位基因多态性与骨密度相关性分析

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Prevalence of vitamin D depletion among subjects seeking advice on osteoporosis: a five-year cross-sectional study with public health implications

Summary We assessed vitamin D nutritional status in unselected consecutive patients seeking advice on osteoporosis. The prevalence of vitamin D depletion ranged from 15–72% depending upon the cut-off levels used for serum 25-hydroxyvitamin D, and the prevalence did not change over the 5 years of the study. Introduction Vitamin D depletion is a significant public health problem and has been studied in different populations using different cut-off levels, but the optimal level is yet to be established. Methods In a cross-sectional study of 2924 patients seen for osteoporosis advice we determined the prevalence of vitamin D depletion, as assessed by 25-hydroxyvitamin D (25-OHD), using three different cut-off levels stratified by gender, race and the year of the study over 5 years. Results Mean age was 68.3 ± 10.0 years; 90% women and 88% white. Mean 25-OHD level was 24.6 ± 10 ng/ml and mean PTH was 48.4 ± 32 pg/ml. The prevalence of vitamin D depletion was 15% with a cut-off level of <15 ng/ml, and rose to 32% and 72% with cut-off levels <20 ng/ml and <30 ng/ml, respectively. The prevalence was higher in men and blacks and remained constant over 5 years, regardless of the cut-off level. The expected inverse relationship between 25-OHD and PTH was observed irrespective of gender or ethnicity. Conclusions The prevalence of vitamin D depletion in patients seeking advice for osteoporosis is high and did not change over the 5 years of the study.     

维生素D对骨关节炎作用的进展

骨关节炎(OA)是我国中老年人常见病、多发病之一,疾病使软骨破坏、软骨下骨质病变和关节周围骨质增生,最终导致关节疼痛、功能障碍甚至是畸形,影响患者活动能力。维生素D具有参与钙磷代谢、改善成骨细胞的活性、促进骨基质的骨化、增加骨密度以及关节软骨的转化等功能,对骨骼健康十分重要。但人体维生素D水平对OA的影响尚未明确,本文就维生素D与OA发展、关节疼痛症状、关节置换术后功能恢复以及补充维生素D后治疗效果等方面相关研究作一综述。     

维生素D缺乏对骨和骨外作用研究进展

维生素D缺乏作为一种在人群中发病率较高的疾病,日益受到人们的广泛关注。维生素D缺乏的主要诊断指标是血清25-羟维生素D水平。大量研究表明,维生素D缺乏不仅可以引起体内钙磷代谢障碍、佝偻病、软骨病和骨质疏松性骨折等骨骼系统疾病,而且还可能引起癌症、免疫系统疾病、心血管疾病、代谢性疾病(2型糖尿病和肥胖症)、肌肉功能障碍和跌倒等其他骨外系统疾病。维生素D缺乏对骨骼系统的作用,目前学术界已形成共识,然而维生素D缺乏对骨外系统的作用,目前学术界存在较大争议。笔者就维生素D缺乏对骨和骨外作用的研究进展进行全面介绍,探讨维生素D具有广泛作用的可能机理。初步阐述维生素D缺乏对骨和骨外系统的作用,不仅为研究维生素D缺乏对骨和骨外作用及可能机理提供新的研究思路,而且为防治维生素D缺乏的相关疾病提供新的临床思路。尽管目前对维生素D缺乏的骨外作用观点不一,但有充分证据表明补充适量的维生素D有助于身体健康。     

The role of vitamin D for bone health and fracture prevention

Vitamin D inadequacy is pandemic in adults. Vitamin D deficiency causes osteopenia, precipitates and exacerbates osteoporosis, causes the painful bone disease osteomalacia, and increases muscle weakness, which worsens the risk of falls and fractures. Vitamin D deficiency can be prevented by sensible sun exposure and adequate supplementation. Monitoring serum 25-hydroxyvitamin D is the only way to determine vitamin D status. Recent recommendations suggest that in the absence of sun exposure, adults should ingest 1000 IU of vitamin D₃ per day. The ideal healthy blood level of 25-hydroxyvitamin D should be 30 to 60 ng/mL. Vitamin D intoxication occurs when 25-hydroxyvitamin D levels are greater than 150 ng/mL. Three recent reports suggesting that vitamin D and calcium supplementation does not decrease the risk of fracture will be put into perspective in light of the vast literature supporting increasing vitamin D and calcium intake as an effective method for decreasing risk of vertebral and nonvertebral fractures.     

A role for vitamin D and the vitamin D receptor in keloid disorder

Keloids are disfiguring fibroproliferative lesions that can occur in susceptible individuals following any skin injury. They are extremely challenging to treat, with relatively low response rates to current therapies and high rates of recurrence after treatment. Although several distinct genetic loci have been associated with keloid formation in different populations, there has been no single causative gene yet identified and the molecular mechanisms guiding keloid development are incompletely understood. Further, although it is well known that keloids are more commonly observed in populations with dark skin pigmentation, the basis for increased keloid risk in skin of colour is not yet known. Because individuals with dark skin pigmentation are at higher risk for vitamin D deficiency, the role of vitamin D in keloid pathology has gained interest in the keloid research community. A limited number of studies have found lower serum vitamin D levels in patients with keloids, and reduced expression of the vitamin D receptor (VDR) in keloid lesions compared with uninjured skin. Vitamin D has documented anti-inflammatory, anti-proliferative and pro-differentiation activities, suggesting it may have a therapeutic role in suppression of keloid fibrosis. Here we review the evidence supporting a role for vitamin D and VDR in keloid pathology.     

现代社会维生素D缺乏及其预防

维生素D缺乏是目前社会所面临的严重健康问题。维生素D(VD)是人体不可缺少的一种脂溶性维生素,其主要作用是增加肠钙的吸收利用,对维持各年龄段骨骼健康矿化都起着非常重要的作用。维生素D缺乏在儿童导致佝偻病;在成年人会发生软骨病和骨质疏松。此外近年来发现维生素D缺乏还与肿瘤、糖尿病、心血管疾病等多种疾病的发生有关,使其重新引起了人们的关注。造成现代社会维生素D缺乏的原因是多方面的,主要是由于各种原因导致的阳光照射不足。血中的25(OH)D的水平可以作为了解人体内VD状况的指标,多数学者认为25(OH)D的水平低于30ng/mL为维生素D不足,现代社会维生素D缺乏发生率非常高,推测全球可能有10亿人口患有维生素D缺乏。合理补充维生素D对预防维生素D缺乏是非常重要的。     

Widespread vitamin D deficiency among Indian health care professionals

Summary

Information on vitamin D status of Indian health care professionals is limited. Among 2,119 subjects studied, just 6?% were found to be sufficient in vitamin D status. There is urgent need of an integrated approach to detect and treat vitamin D deficiency among health care professionals to improve on-the-job productivity.

Introduction

Vitamin D deficiency is prevalent worldwide. India has been reported to be one of the worst affected countries. Several single-center studies from India have shown high prevalence of vitamin D deficiency. Little is known regarding the vitamin D status of Indian health care professionals.

Aim

This study aimed to determine prevalence of vitamin D deficiency among health care professionals in different regions of India.

Method

In this cross-sectional, multicenter study, we enrolled 2,119 medical and paramedical personnel from 18 Indian cities. Blood samples were collected from December 2010 to March 2011 and analyzed in a central laboratory by radioimmunoassay. Vitamin D deficiency was defined as 25-hydroxyvitamin D [25(OH)D] <20?ng/mL or <50?nmol/L, insufficiency as 25(OH)D?=?20?C30?ng/mL or 50?C75?nmol/L, and sufficiency as 25(OH)D >30?ng/mL or >75?nmol/L.

Results

Mean (±SD) age of subjects was 42.71?±?6.8?years. Mean (±SD) 25(OH)D level was 14.35?±?10.62?ng/mL (median 11.93?ng/mL). Seventy-nine percent of subjects were deficient, 15?% were insufficient, and just 6?% were sufficient in vitamin D status. No significant difference was found between vitamin D status in southern (25(OH)D?=?13.3?±?6.4?ng/mL) and northern (25(OH)D?=?14.4?±?8.5?ng/mL) parts of India.

Conclusion

Our study confirms the high prevalence of vitamin D deficiency all across India in apparently healthy, middle-aged health care professionals.