Low Vitamin D Status Among Obese Adolescents: Prevalence and Response to Treatment

Purpose: 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. (C) 2011 Published by Elsevier Inc. on behalf of Society for Adolescent Health and Medicine.