title: Low vitamin D status among obese adolescents: prevalence and response to treatment.
abstract: OBJECTIVE
  To explore the prevalence of low vitamin D status among obese adolescents and to examine the effect of current management of low vitamin D status in these patients.
  
  
  METHODS
  A retrospective chart review of obese adolescents who had been screened for vitamin D status by serum total 25-hydroxyvitamin D (25(OH)D) level. Vitamin D deficiency was defined as 25(OH)D level of <20 ng/mL, vitamin D insufficiency as 25(OH)D level of 20-30 ng/mL, and vitamin D sufficiency as 25(OH)D level of >30 ng/mL. Adolescents with vitamin D deficiency were treated with 50,000 IU of vitamin D once a week for 6-8 weeks, whereas adolescents with vitamin D insufficiency were treated with 800 IU of vitamin D daily for 3 months. Repeat 25(OH)D was obtained after treatment.
  
  
  RESULTS
  The prevalence rate of low vitamin D status among 68 obese adolescents (53% females, 47% males, age: 17 ± 1 years, body mass index: 38 ± 1 kg/m(2), Hispanic: 45%, African American: 40%, Caucasian: 15%) was 100% in females and 91% in males. Mean (±SE) 25(OH)D level was significantly higher in summer (20 ± 8 ng/mL) than in spring (14 ± 4 ng/mL, p < .02), and significantly lower in winter (15 ± 7 ng/mL) than in fall (25 ± 15 ng/mL, p < .05). Although there was a significant (p < .00001) increase in mean 25(OH)D after the initial course of treatment with vitamin D, 25(OH)D levels normalized in only 28% of the participants. Repeat courses with the same dosage in the other 72% did not significantly change their low vitamin D status.
  
  
  CONCLUSIONS
  Increased surveillance and possibly higher vitamin D doses are warranted for obese adolescents whose total 25(OH)D levels do not normalize after the initial course of treatment.
authors.affiliation: Division of Adolescent Medicine, Hasbro Children's Hospital, Providence, RI 02903, USA. zharel@lifespan.org
authors.forename: Zeev
authors.initials: Z
authors.lastname: Harel
authors.forename: Patricia
authors.initials: P
authors.lastname: Flanagan
authors.forename: Michelle
authors.initials: M
authors.lastname: Forcier
authors.forename: Dalia
authors.initials: D
authors.lastname: Harel
mesh_terms: D000293:Adolescent; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D008485:Medical Audit; D009765:Obesity; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D012237:Rhode Island / Q000453:epidemiology; D014808:Vitamin D Deficiency / Q000178:diet therapy* / Q000453:epidemiology*