title: Vitamin D status in Norwegian children and adolescents with excess body weight.
abstract: OBJECTIVE
  The prevalence of childhood and adolescent obesity has increased during the past decades. A high body mass index (BMI) is associated with a low vitamin D status. The purpose of this study was to determine the prevalence of vitamin D deficiency and insufficiency in Norwegian children and adolescents with excess body weight.
  
  
  METHODS
  Vitamin D status and seasonal variations of 25(OH)D and 1,25(OH)(2)D were analyzed in 102 children and adolescents (70 girls and 32 boys), 8-19 yr of age, with overweight and obesity.
  
  
  RESULTS
  Overall, 50% of the children and adolescents included in the study had a low vitamin D status (25(OH)D <75 nmol/L) and 19% had vitamin D deficiency (25(OH)D <50 nmol/L). This was most prevalent in adolescents. Only 42% of teenagers had 25(OH)D levels ≥75 nmol/L vs. 72% of preteens. Both 25(OH)D and 1,25(OH)(2)D showed seasonal variations. A peak in serum 25(OH)D concentrations was observed during the summer while the lowest values were seen during the spring. In contrast, serum 1,25(OH)(2)D had a peak during the spring and the lowest concentrations during the winter.
  
  
  CONCLUSIONS
  The prevalence of vitamin D deficiency and insufficiency is higher in obese and overweight adolescents than in overweight children. This might be related to low outdoor activities and low vitamin D intake in teenagers. Seasonal variations of both the vitamin D metabolites were observed.
authors.affiliation: Department of Radiation Biology, Oslo University Hospital, The Norwegian Radium Hospital, 0310 Oslo, Norway. zoya.lagunova@rr-research.no
authors.forename: Zoya
authors.initials: Z
authors.lastname: Lagunova
authors.forename: Alina C
authors.initials: AC
authors.lastname: Porojnicu
authors.forename: Fedon A
authors.initials: FA
authors.lastname: Lindberg
authors.forename: Lage
authors.initials: L
authors.lastname: Aksnes
authors.forename: Johan
authors.initials: J
authors.lastname: Moan
mesh_terms: D000293:Adolescent; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009664:Norway / Q000453:epidemiology; D009752:Nutritional Status / Q000502:physiology; D050177:Overweight / Q000097:blood* / Q000453:epidemiology*; D012621:Seasons; D014807:Vitamin D / Q000097:blood*; D055815:Young Adult
chemical_list: D014807:Vitamin D