目标:中东和北非(MENA)地区记录了一些最低的血清25-羟基维生素D[25(OH)D]浓度,全世界。我们描述了维生素D缺乏症的患病率和危险因素,已完成和正在进行的临床试验,以及该地区补充维生素D的可用指南。
方法:本综述是我们小组在2013年发表的观察性研究综述的更新,2015年为该地区的随机对照试验(RCT)。我们在Medline进行了全面搜索,PubMed,和Embase,还有Cochrane图书馆,使用与维生素D相关的MeSH术语和关键词,维生素D缺乏,中东和北非地区,2012-2017年期间的观察性研究,和RCT的2015-2017年。我们纳入了至少100名受试者/研究的大型横断面研究,和RCT,每个手臂至少有50名参与者。
结果:我们确定了41项观察性研究。维生素D缺乏症的患病率,定义为25-羟基维生素D[25(OH)D]水平低于20ng/ml的理想水平,儿童和青少年的比例在12-96%之间,和54-90%的孕妇。在成年人中,介于44%到96%之间,平均25(OH)D在11至20ng/ml之间变化。总的来说,25(OH)D水平低的重要预测因素是女性,增加年龄和体重指数,面纱,冬季,使用防晒霜,较低的社会经济地位,和更高的纬度。我们检索了14项RCT,将补充剂与对照或安慰剂进行比较,在2015-2017年期间发表:2在儿童中,8、成人和4孕妇。在儿童和青少年中,需要1000-2000IU/d的维生素D剂量才能将血清25(OH)D水平维持在目标水平.在成人和孕妇中,25(OH)D水平的增量与剂量成反比,剂量≤2000IU/d时,每100IU/d为0.9至3ng/ml,剂量≥3000IU/d时,每100IU/d为0.1至0.6ng/ml。虽然补充维生素D对成人血糖指数的影响仍然存在争议,补充维生素D可能对孕妇预防妊娠期糖尿病有保护作用.在唯一确定的老年人研究中,600IU/天和3750IU/天剂量对骨矿物质密度没有显着差异。我们没有发现任何骨折研究。该地区可用的维生素D指南基于专家意见,推荐剂量在400到2000IU/d之间,根据年龄类别,和国家。
结论:低维生素D在MENA地区普遍存在,和1000-2000IU/d的剂量可能是必要的,以达到20ng/ml的理想25(OH)D水平。评估这种剂量的维生素D对主要结果的影响的研究,并确认他们的长期安全,是需要的。
OBJECTIVE: The Middle East and North Africa (MENA) region registers some of the lowest serum 25‑hydroxyvitamin D [25(OH)D] concentrations, worldwide. We describe the prevalence and the risk factors for hypovitaminosis D, completed and ongoing clinical trials, and available guidelines for vitamin D supplementation in this region.
METHODS: This review is an update of previous reviews published by our group in 2013 for observational studies, and in 2015 for randomized controlled trials (RCTs) from the region. We conducted a comprehensive search in Medline, PubMed, and Embase, and the Cochrane Library, using MeSH terms and keywords relevant to vitamin D, vitamin D deficiency, and the MENA region, for the period 2012-2017 for observational studies, and 2015-2017 for RCTs. We included large cross-sectional studies with at least 100 subjects/study, and RCTs with at least 50 participants per arm.
RESULTS: We identified 41 observational studies. The prevalence of hypovitaminosis D, defined as a 25‑hydroxyvitamin D [25(OH)D] level below the desirable level of 20 ng/ml, ranged between 12-96% in children and adolescents, and 54-90% in pregnant women. In adults, it ranged between 44 and 96%, and the mean 25(OH)D varied between 11 and 20 ng/ml. In general, significant predictors of low 25(OH)D levels were female gender, increasing age and body mass index, veiling, winter season, use of sun screens, lower socioeconomic status, and higher latitude.We retrieved 14 RCTs comparing supplementation to control or placebo, published during the period 2015-2017: 2 in children, 8 in adults, and 4 in pregnant women. In children and adolescents, a vitamin D dose of 1000-2000 IU/d was needed to maintain serum 25(OH)D level at target. In adults and pregnant women, the increment in 25(OH)D level was inversely proportional to the dose, ranging between 0.9 and 3 ng/ml per 100 IU/d for doses ≤2000 IU/d, and between 0.1 and 0.6 ng/ml per 100 IU/d for doses ≥3000 IU/d. While the effect of vitamin D supplementation on glycemic indices is still controversial in adults, vitamin D supplementation may be protective against gestational diabetes mellitus in pregnant women. In the only identified study in the elderly, there was no significant difference between 600 IU/day and 3750 IU/day doses on bone mineral density. We did not identify any fracture studies.The available vitamin D guidelines in the region are based on expert opinion, with recommended doses between 400 and 2000 IU/d, depending on the age category, and country.
CONCLUSIONS: Hypovitaminosis D is prevalent in the MENA region, and doses of 1000-2000 IU/d may be necessary to reach a desirable 25(OH)D level of 20 ng/ml. Studies assessing the effect of such doses of vitamin D on major outcomes, and confirming their long term safety, are needed.