title: Linking vitamin D status, executive functioning and self-perceived mental health in adolescents through multivariate analysis: A randomized double-blind placebo control trial.
abstract: The aim of the present randomized double-blind placebo control trial was to investigate if vitamin D supplementation had an effect on vitamin D status, executive functioning and self-perceived mental health in a group of Norwegian adolescents during winter time. Fifty adolescents were randomly assigned into an intervention group (vitamin D pearls) or a control group (placebo pearls). Before (pre-test in December/January) and after (post-test in April/May) the intervention period the participants were exposed to a test procedure, consisting of blood draw, completion of cognitive tests (Tower of Hanoi and Tower of London), and the Youth Self-report version of the Child Behavior Checklist. Multivariate data analysis showed that participants with low vitamin D status scored worse on the Tower of London tests and the more difficult sub-tasks on the Tower of Hanoi tests. They also had a tendency to report higher frequency of externalizing behavior problems and attention deficit. At pre-test, the overall mean vitamin D status measured as 25-hydroxy vitamin D was 42 nmol/L, defining deficiency (Intervention group = 44 nmol/L, Control group = 39 nmol/L). However, vitamin D supplementation caused a significant increase in vitamin D status resulting in a sufficient level in the Intervention group at post-test (mean 62 nmol/L). The results also revealed that the intervention group improved their performance on the most demanding sub-tasks on the ToH. Overall, the study indicates that vitamin D status in adolescents may be important for both executive functioning and mental health.
authors.affiliation: Department of Chemistry, University of Bergen, Allégaten 41, 5007, Bergen, Norway.
authors.forename: Bjørn
authors.initials: B
authors.lastname: Grung
authors.affiliation: Norwegian Police University College, Helgeroveien 9, 3291, Stavern, Norway.
authors.forename: Asle M
authors.initials: AM
authors.lastname: Sandvik
authors.affiliation: Department of Clinical Psychology, University of Bergen, Christiesgt. 12, 5015, Bergen, Norway.
authors.forename: Kay
authors.initials: K
authors.lastname: Hjelle
authors.affiliation: National Institute of Nutrition and Seafood Research (NIFES), PO Box 2029, Nordnes, 5817, Bergen, Norway.
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Dahl
authors.affiliation: National Institute of Nutrition and Seafood Research (NIFES), PO Box 2029, Nordnes, 5817, Bergen, Norway.
authors.forename: Livar
authors.initials: L
authors.lastname: Frøyland
authors.affiliation: Department of Biomedical Laboratory Sciences and Chemical Engineering, Bergen University College.
authors.forename: Irene
authors.initials: I
authors.lastname: Nygård
authors.affiliation: Department of Clinical Psychology, University of Bergen, Christiesgt. 12, 5015, Bergen, Norway.|Centre for Research and Education in Forensic Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors.forename: Anita L
authors.initials: AL
authors.lastname: Hansen
mesh_terms: D000293:Adolescent; D004311:Double-Blind Method; D056344:Executive Function; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D008603:Mental Health; D015999:Multivariate Analysis; D009664:Norway; D011581:Psychological Tests; D012621:Seasons; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood; D014808:Vitamin D Deficiency / Q000523:psychology
chemical_list: D014807:Vitamin D
keywords: Vitamin D; adolescents; executive functions; intervention study; mental health; multivariate analysis