title: Low 25-hydroxyvitamin D levels in adolescents: race, season, adiposity, physical activity, and fitness.
abstract: OBJECTIVE
  The objectives were to characterize the vitamin D status of black and white adolescents residing in the southeastern United States (latitude: approximately 33 degrees N) and to investigate relationships with adiposity.
  
  
  METHODS
  Plasma 25-hydroxyvitamin D levels were measured with liquid chromatography-tandem mass spectroscopy for 559 adolescents 14 to 18 years of age (45% black and 49% female). Fat tissues, physical activity, and cardiovascular fitness also were measured.
  
  
  RESULTS
  The overall prevalences of vitamin D insufficiency (<75 nmol/L) and deficiency (< or = 50 nmol/L) were 56.4% and 28.8%, respectively. Black versus white subjects had significantly lower plasma 25-hydroxyvitamin D levels in every season (winter, 35.9 + or - 2.5 vs 77.4 + or - 2.7 nmol/L; spring, 46.4 + or - 3.5 vs 101.3 + or - 3.5 nmol/L; summer, 50.7 + or - 4.0 vs 104.3 + or - 4.0 nmol/L; autumn, 54.4 + or - 4.0 vs 96.8 + or - 2.7 nmol/L). With adjustment for age, gender, race, season, height, and sexual maturation, there were significant inverse correlations between 25-hydroxyvitamin D levels and all adiposity measurements, including BMI percentile (P = .02), waist circumference (P < .01), total fat mass (P < .01), percentage of body fat (P < .01), visceral adipose tissue (P = .015), and subcutaneous abdominal adipose tissue (P = .039). There were significant positive associations between 25-hydroxyvitamin D levels and vigorous physical activity (P < .01) and cardiovascular fitness (P = .025).
  
  
  CONCLUSIONS
  Low vitamin D status is prevalent among adolescents living in a year-round sunny climate, particularly among black youths. The relationships between 25-hydroxyvitamin D levels, adiposity, physical activity, and fitness seem to be present in adolescence.
authors.affiliation: Medical College of Georgia, Department of Pediatrics, Georgia Prevention Institute, 1120 15th St, HS-1640, Augusta, GA 30912, USA. ydong@mail.mcg.edu
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Dong
authors.forename: Norman
authors.initials: N
authors.lastname: Pollock
authors.forename: Inger Susanne
authors.initials: IS
authors.lastname: Stallmann-Jorgensen
authors.forename: Bernard
authors.initials: B
authors.lastname: Gutin
authors.forename: Ling
authors.initials: L
authors.lastname: Lan
authors.forename: Tai C
authors.initials: TC
authors.lastname: Chen
authors.forename: Daniel
authors.initials: D
authors.lastname: Keeton
authors.forename: Karen
authors.initials: K
authors.lastname: Petty
authors.forename: Michael F
authors.initials: MF
authors.lastname: Holick
authors.forename: Haidong
authors.initials: H
authors.lastname: Zhu
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000293:Adolescent; D001741:Black or African American / Q000706:statistics & numerical data*; D015992:Body Mass Index; D002853:Chromatography, Liquid; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D015995:Prevalence; D012621:Seasons; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*; D044465:White People / Q000706:statistics & numerical data*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D