title: Vitamin D deficiency/insufficiency and challenges in developing global vitamin D fortification and supplementation policy in adults.
abstract: This review summarizes studies discussing vitamin D status in adults and reveals that vitamin D deficiency/insufficiency is highly prevalent in adults and that current fortification and supplementation policies are inadequate.
  
  
  OBJECTIVE
  Studies suggest a crucial role for adequate vitamin D status in various health conditions including bone metabolism, cancer, cardiovascular diseases, and allergies. However, relatively little is known about poor vitamin D status and unmet needs in adults. This report aims to highlight the contribution of epidemiologic studies (through the identification of health effects and societal burden) to the development of vitamin D fortification and supplementation policies and reveal unmet global challenges in adults.
  
  
  METHODS
  In order to assess worldwide vitamin D status in adults, the search strategy combined the medical literature database MEDLINE (using PubMed) for the time period between January 1, 1980 and February 28, 2011, using the key words "vitamin D" "deficiency" and "insufficiency", and included articles in which access to full text was possible and in which healthy adults were assessed according to one of four commonly used vitamin D threshold classifications.
  
  
  RESULTS
  This report reveals that vitamin D deficiency occurs in 4.10 % [95 % CI (confidence interval), 3.93 %, 4.27 %] to 55.05 % (54.07 %, 56.03 %) of adults, while insufficiency occurs in 26.07 % (24.82 %, 27.33 %) to 78.50 % (77.85 %, 79.16 %), depending on the classification used. However, lack of overlap in CIs and high value of I2 statistics indicate considerable heterogeneity between studies. Further, certain populations (i. e. dark-skinned individuals, immigrants, and pregnant women) may be at higher risk for poor vitamin D status.
  
  
  CONCLUSIONS
  Current policies for vitamin D supplementation and fortification are inadequate and new guidelines are required to improve vitamin D status in adults.
authors.affiliation: Division of Pediatric Allergy and Clinical Immunology, Department of Pediatrics, McGill University Health Center, Montreal, Quebec, Canada. moshebenshoshan@gmail.com
authors.forename: Moshe
authors.initials: M
authors.lastname: Ben-Shoshan
mesh_terms: D000328:Adult; D019587:Dietary Supplements; D005260:Female; D005527:Food, Fortified; D006304:Health Status; D006801:Humans; D016239:MEDLINE; D018673:Nutrition Policy; D009752:Nutritional Status; D011247:Pregnancy; D012307:Risk Factors; D014807:Vitamin D / Q000008:administration & dosage / Q000502:physiology; D014808:Vitamin D Deficiency / Q000453:epidemiology* / Q000517:prevention & control*
chemical_list: D014807:Vitamin D