title: Impact of vitamin D replacement in adults and elderly in the Middle East and North Africa: a systematic review and meta-analysis of randomized controlled trials.
abstract: In the Middle East and North Africa (MENA), a vitamin D dose ≥2000 IU/day may be needed to allow to the majority of the population to reach the target 25-hydroxyvitamin D (25(OH)D) level ≥20 ng/ml. Data in the region on the effect of vitamin D supplementation on various skeletal and extra-skeletal effects are scarce.
  
  
  
  Hypovitaminosis D is prevalent worldwide, more so in the Middle East and North Africa (MENA). This study aims to determine the effects of vitamin D replacement on the mean difference in 25-hydroxyvitamin D [25(OH)D] level reached and other outcomes, in the MENA.
  
  
  
  This is a meta-analysis of randomized trials from the MENA, administering vitamin D supplementation for at least 3 months, without language or time restriction. We conducted a comprehensive search in seven databases until July 2015. We abstracted data from published reports, independently and in duplicate. We calculated the mean difference (MD) and 95 % CI of 25(OH)D level reached for eligible comparisons, and pooled data using RevMan version 5.3.
  
  
  
  We identified 2 studies in elderly and 17 in adults; for the latter, 11 were included in the meta-analysis. Comparing a high vitamin D dose (>2000 IU/day) to placebo (nine studies), the MD in 25(OH)D level achieved was 18.3 (CI 14.1; 22.5) ng/ml; p value < 0.001; I2= 92 %. Comparing an intermediate dose (800-2000 IU/day) to placebo (two studies), the MD in 25(OH)D level achieved was 14.7 (CI 4.6; 24.9) ng/ml; p value 0.004; I2= 91 %. Accordingly, 89 and 71 % of participants, in the high and intermediate dose groups, respectively, reached the desirable level of 20 ng/ml. The risk of bias in the included studies was unclear to high, except for three studies.
  
  
  
  In the MENA region, vitamin D doses ≥2000 IU/day may be needed to reach the target 25(OH)D level ≥20 ng/ml. The long-term safety and the efficacy of such doses on various outcomes are unknown.
authors.affiliation: Calcium Metabolism and Osteoporosis Program, WHO Collaborating Center for Metabolic Bone Disorders, American University of Beirut Medical Center, P.O. Box: 113-6044/C8, Beirut, Lebanon. mc39@aub.edu.lb.
authors.forename: M
authors.initials: M
authors.lastname: Chakhtoura
authors.affiliation: Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: E A
authors.initials: EA
authors.lastname: Akl
authors.affiliation: Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: S
authors.initials: S
authors.lastname: El Ghandour
authors.affiliation: Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: K
authors.initials: K
authors.lastname: Shawwa
authors.affiliation: Calcium Metabolism and Osteoporosis Program, WHO Collaborating Center for Metabolic Bone Disorders, American University of Beirut Medical Center, P.O. Box: 113-6044/C8, Beirut, Lebanon.
authors.forename: A
authors.initials: A
authors.lastname: Arabi
authors.affiliation: Department of Medical Education, Weill Cornell Medicine, Doha, Qatar.
authors.forename: Z
authors.initials: Z
authors.lastname: Mahfoud
authors.affiliation: Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: R H
authors.initials: RH
authors.lastname: Habib
authors.affiliation: Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: H
authors.initials: H
authors.lastname: Hoballah
authors.affiliation: Calcium Metabolism and Osteoporosis Program, WHO Collaborating Center for Metabolic Bone Disorders, American University of Beirut Medical Center, P.O. Box: 113-6044/C8, Beirut, Lebanon.
authors.forename: G
authors.initials: G
authors.lastname: El Hajj Fuleihan
mesh_terms: D000352:Africa, Northern / Q000453:epidemiology; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008877:Middle East / Q000453:epidemiology; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Meta-analysis; Meta-regression; Middle East and North Africa; Vitamin D