Hypovitaminosis D among healthy children in the United States: a review of the current evidence.
OBJECTIVE
To review the published literature on serum 25-hydroxyvitamin D concentrations in US children.


METHODS
Articles were identified by searching MEDLINE using 25-hydroxyvitamin D, vitamin D, hypovitaminosis D, vitamin D insufficiency, vitamin D deficiency, children, and adolescents as key words and by screening references from original studies.


METHODS
Studies were included if they fulfilled the following a priori criteria: contained a well-defined sample of children, included only healthy children, presented data on serum 25-hydroxyvitamin D concentrations, were published in the past 10 years, and were conducted in the United States.


METHODS
Serum 25-hydroxyvitamin D concentrations and prevalence of low vitamin D status (hypovitaminosis D).


RESULTS
Fourteen articles fulfilled the criteria. There were no consistent definitions of hypovitaminosis D; values corresponding to vitamin D deficiency ranged from less than 5 ng/mL to less than 12 ng/mL, and those for vitamin D insufficiency ranged from less than 10 ng/mL to less than 32 ng/mL (to convert 25-hydroxyvitamin D concentrations to nanomoles per liter, multiply by 2.496). The following assays were used: radioimmunoassay (7 studies), competitive binding protein assay (3 studies), automated chemiluminescence protein-binding assay (3 studies), and enzyme-linked immunosorbent assay (1 study). Breastfed infants in winter who did not receive vitamin D supplementation were the most severely vitamin D deficient (78%). Estimates of the prevalence of hypovitaminosis D ranged from 1% to 78%. Older age, winter season, higher body mass index, black race/ethnicity, and elevated parathyroid hormone concentrations were associated with lower 25-hydroxyvitamin D concentrations.


CONCLUSIONS
Although overt vitamin D deficiency is no longer common in US children, lesser degrees of vitamin D insufficiency are widespread.
Division of Epidemiology, Statistics and Prevention, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Blvd, Room 7B13A, MSC 7510, Rockville, MD 20852, USA. rovneral@mail.nih.gov
Alisha J
AJ
Rovner
Kimberly O
KO
O'Brien
D000293:Adolescent; D000328:Adult; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006304:Health Status; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008163:Luminescent Measurements; D008297:Male; D009752:Nutritional Status; D010758:Phosphorus / Q000378:metabolism; D011863:Radioimmunoassay; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology*
D014807:Vitamin D; D010758:Phosphorus; C104450:25-hydroxyvitamin D; D002118:Calcium