Vitamin D status and response to Vitamin D(3) in obese vs. non-obese African American children.
BACKGROUND
Serum 25-hydroxyvitamin D (25(OH)D) is low in obese adults.


OBJECTIVE
To examine serum 25(OH)D in obese (BMI >95th percentile for age) vs. non-obese (BMI = 5th-75th percentile for age) 6-10-year-old African American children and compare their differences in therapeutic response to vitamin D supplementation.


METHODS
In an open label non-randomized pre-post comparison 21 obese (OB) and 20 non-obese (non-OB) subjects matched for age, sex, skin color, and pubertal maturation were treated with 400 IU of vitamin D(3) daily for 1 month. Serum 25(OH)D, 1,25-dihydroxyvitamin D (1,25(OH)(2)D), parathyroid hormone (PTH), leptin, and markers of bone turnover (serum bone-specific alkaline phosphatase (BSAP), osteocalcin (OC), and urine n -telopeptide cross-links of type 1 collagen (urine NTX)) were measured. Vitamin D deficiency was defined as serum 25(OH)D < or =20 ng/ml and insufficiency as 21-29 ng/ml respectively.


RESULTS
Vitamin D deficiency occurred in 12/21 (57%) OB vs. 8/20 (40%) non-OB at baseline (P = 0.35) and persisted in 5/21 (24%) OB vs. 2/18 (11%) non-OB (P = 0.42) after treatment. When the cohort was stratified by the baseline levels of 25(OH)D, there were differences in the response to treatment in the obese and non-obese cohorts.


CONCLUSIONS
Vitamin D deficiency was common among OB and non-OB preadolescent African American children, and 400 IU of vitamin D(3) (2x the recommended adequate intake) daily for 1 month was inadequate to raise their blood levels of 25(OH)D to > or =30 ng/ml.
Rajakumar
Kumaravel
K
Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA. Kumaravel.Rajakumar@chp.edu
Fernstrom
John D
JD
Holick
Michael F
MF
Janosky
Janine E
JE
Greenspan
Susan L
SL
D001741:Black or African American / Q000208:ethnology; D000469:Alkaline Phosphatase / Q000097:blood; D001842:Bone and Bones / Q000378:metabolism; D002648:Child; D024042:Collagen Type I / Q000652:urine; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood; D008297:Male; D009765:Obesity / Q000208:ethnology / Q000378:metabolism*; D015675:Osteocalcin / Q000097:blood; D010349:Patient Compliance; D010455:Peptides / Q000652:urine; D015995:Prevalence; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy* / Q000208:ethnology
D024042:Collagen Type I; D020738:Leptin; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D000469:Alkaline Phosphatase