title: Prevalence and predictors of vitamin D insufficiency in children: a Great Britain population based study.
abstract: OBJECTIVE
  To evaluate the prevalence and predictors of vitamin D insufficiency (VDI) in children in Great Britain.
  
  
  METHODS
  A nationally representative cross-sectional study survey of children (1102) aged 4-18 years (999 white, 570 male) living in private households (January 1997-1998). Interventions provided information about dietary habits, physical activity, socio-demographics, and blood sample. Outcome measures were vitamin D insufficiency (<50 nmol/L).
  
  
  RESULTS
  Vitamin D levels (mean = 62.1 nmol/L, 95%CI 60.4-63.7) were insufficient in 35%, and decreased with age in both sexes (p<0.001). Young People living between 53-59 degrees latitude had lower levels (compared with 50-53 degrees, p = 0.045). Dietary intake and gender had no effect on vitamin D status. A logistic regression model showed increased risk of VDI in the following: adolescents (14-18 years old), odds ratio (OR) = 3.6 (95%CI 1.8-7.2) compared with younger children (4-8 years); non white children (OR = 37 [95%CI 15-90]); blood levels taken December-May (OR = 6.5 [95%CI 4.3-10.1]); on income support (OR = 2.2 [95%CI 1.3-3.9]); not taking vitamin D supplementation (OR = 3.7 [95%CI 1.4-9.8]); being overweight (OR 1.6 [95%CI 1.0-2.5]); <1/2 hour outdoor exercise/day/week (OR = 1.5 [95%CI 1.0-2.3]); watched >2.5 hours of TV/day/week (OR = 1.6[95%CI 1.0-2.4]).
  
  
  CONCLUSIONS
  We confirm a previously under-recognised risk of VDI in adolescents. The marked higher risk for VDI in non-white children suggests they should be targeted in any preventative strategies. The association of higher risk of VDI among children who exercised less outdoors, watched more TV and were overweight highlights potentially modifiable risk factors. Clearer guidelines and an increased awareness especially in adolescents are needed, as there are no recommendations for vitamin D supplementation in older children.
authors.affiliation: School of Health and Population Sciences, University of Birmingham, Birmingham, United Kingdom. michaelabsoud@childdemyelination.org.uk
authors.forename: Michael
authors.initials: M
authors.lastname: Absoud
authors.forename: Carole
authors.initials: C
authors.lastname: Cummins
authors.forename: Ming J
authors.initials: MJ
authors.lastname: Lim
authors.forename: Evangeline
authors.initials: E
authors.lastname: Wassmer
authors.forename: Nick
authors.initials: N
authors.lastname: Shaw
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009749:Nutrition Surveys; D011379:Prognosis; D006113:United Kingdom / Q000453:epidemiology; D014808:Vitamin D Deficiency / Q000175:diagnosis* / Q000453:epidemiology*