title: Towards evidence-based vitamin D supplementation in infants: vitamin D intervention in infants (VIDI) - study design and methods of a randomised controlled double-blinded intervention study.
abstract: Vitamin D is important for bone mass accrual during growth. Additionally, it is considered a requirement for a multitude of processes associated with, for example, the development of immunity. Many countries apply vitamin D supplementation strategies in infants, but the guidelines are not based on scientific evidence and aim at prevention of rickets. It remains unclear whether the recommended doses are sufficient for the wide array of other effects of vitamin D. The VIDI trial performed in Finland is the first large randomised controlled study for evaluation of the effects of different vitamin D supplemental doses in infancy on: 1. bone strength 2. infections and immunity 3. allergy, atopy and asthma 4. cognitive development 5. genetic regulation of mineral homeostasis METHODS/DESIGN: VIDI, a randomised controlled double-blinded single-centre intervention study is conducted in infants from the age of 2 weeks to 24 months. Participants, recruited at Helsinki Maternity Hospital, are randomised to receive daily either 10 μg (400 IU) or 30 μg (1 200 IU) of vitamin D3 supplementation. Both groups are assessed at 6 months of age for calcium homeostasis, and at 12 and 24 months of age for parameters associated with bone strength, growth, developmental milestones, infections, immunity, atopy-related diseases, and genetic factors involved in these functions.
  
  
  
  The study enables evaluation of short and long term effects of supplemental vitamin D on growth, immune functions and skeletal and developmental parameters in infants, and the effects of genetic factors therein. The results enable institution of evidence-based guidelines for vitamin D supplementation in infancy.
  
  
  
  ClinicalTrials.gov, NCT01723852 , registration date 6.11.2012.
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland. otto.helve@helsinki.fi.
authors.forename: Otto
authors.identifier: 0000-0001-6254-3180
authors.initials: O
authors.lastname: Helve
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.|Folkhälsan Research Center, Helsinki, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Viljakainen
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.
authors.forename: Elisa
authors.initials: E
authors.lastname: Holmlund-Suila
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.
authors.forename: Jenni
authors.initials: J
authors.lastname: Rosendahl
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.
authors.forename: Helena
authors.initials: H
authors.lastname: Hauta-Alus
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.
authors.forename: Maria
authors.initials: M
authors.lastname: Enlund-Cerullo
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.
authors.forename: Saara
authors.initials: S
authors.lastname: Valkama
authors.affiliation: Institute of Behavioral Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Kati
authors.initials: K
authors.lastname: Heinonen
authors.affiliation: Institute of Behavioral Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Katri
authors.initials: K
authors.lastname: Räikkönen
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Hytinantti
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.|Folkhälsan Research Center, Helsinki, Finland.|Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Outi
authors.initials: O
authors.lastname: Mäkitie
authors.affiliation: Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, P.O. Box 281, 00029 HUS, Helsinki, Finland.
authors.forename: Sture
authors.initials: S
authors.lastname: Andersson
mesh_terms: D001846:Bone Development / Q000187:drug effects; D002657:Child Development / Q000187:drug effects; D002675:Child, Preschool; D002762:Cholecalciferol / Q000494:pharmacology / Q000627:therapeutic use*; D002985:Clinical Protocols; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D007107:Immune System / Q000187:drug effects; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016896:Treatment Outcome; D014808:Vitamin D Deficiency / Q000150:complications / Q000517:prevention & control*; D014815:Vitamins / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D014815:Vitamins; D002762:Cholecalciferol
keywords: Allergy; Asthma; Bone development; Cognitive development; Immunity; Infants; Infections; Vitamin D