title: Can vitamin D status be assessed by serum 25OHD in children?
abstract: BACKGROUND
  To examine the relationship of serum 25-hydroxyvitamin D (25OHD) concentrations with serum parathyroid hormone (PTH) levels, body mass index (BMI), and environmental factors in a population of Caucasian children living at latitude 43°N.
  
  
  METHODS
  Cross-sectional study on 288 children aged 1 month to 13 years who presented to a pediatric emergency unit during a 21-month period.
  
  
  RESULTS
  Mean (SD) serum 25OHD concentrations were 40.6 (17.6), 30.9 (12.0), and 26.4 (9.9) ng/ml (1 ng/ml = 2.5 nmol/l), in children aged 0-1, 2-5, and ≥ 6 years, respectively. Serum PTH levels were 26.6 (13.6), 24.3 (11.9), and 32.7 (12.1) pg/ml in the same groups. Infants had 25OHD concentrations significantly higher. PTH levels were significantly higher in children aged ≥ 6 years. There was no significant correlation between serum 25OHD and PTH concentrations. Totals of 15.6 % and 2.1 % of children had 25OHD values less than 20 and 10 ng/ml, respectively, but none had elevated serum PTH or clinical manifestations related with vitamin D deficiency. Age (inverse correlation) and season (higher values in summer), but not BMI, sex, and time spent outdoors, influenced serum 25OHD concentrations.
  
  
  CONCLUSIONS
  Our results raise doubt on the assumption of only a serum 25OHD threshold as indicative of vitamin D deficiency in children.
authors.affiliation: Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, 33011, Spain, maruchialonso@gmail.com.
authors.forename: María Agustina
authors.initials: MA
authors.lastname: Alonso
authors.forename: Zamir Francisco
authors.initials: ZF
authors.lastname: Pallavicini
authors.forename: Julián
authors.initials: J
authors.lastname: Rodríguez
authors.forename: Noelia
authors.initials: N
authors.lastname: Avello
authors.forename: Pablo
authors.initials: P
authors.lastname: Martínez-Camblor
authors.forename: Fernando
authors.initials: F
authors.lastname: Santos
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008163:Luminescent Measurements; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood*; D013030:Spain; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000175:diagnosis*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D