title: Serum 25-hydroxyvitamin D levels in preschool-age children in northern Sweden are inadequate after summer and diminish further during winter.
abstract: OBJECTIVE
  Despite studies indicating that vitamin D intake among Swedish children does not meet the recommendation, little is known of their vitamin D status. The aim of the present study was to examine vitamin D status in preschool-age children in relation to vitamin D intake, season, body mass index, and skin color.
  
  
  METHODS
  Preschool-age children (n = 90; mean age 54 ± 7.1 months), all living in northern Sweden (latitude 63° north), half of them with fair skin, half with darker complexion, were recruited from well-baby clinics. The study group was examined first in August-September (late summer) and then the following January-February (winter). Skin type, vitamin D intake, anthropometrics, serum 25-hydroxyvitamin D (S-25[OH] D), and serum parathyroid hormone were assessed.
  
  
  RESULTS
  Mean ± SD S-25(OH) D in summer and winter were 60 ± 15 nmol/L and 55 ± 16 nmol/L, respectively (P < 0.001). Fifteen percent and 10% had S-25(OH) D ≥ 75 nmol/L, and 25% and 40% had S-25(OH) D <50 nmol/L, respectively. The mean vitamin D intake was higher in dark-skinned compared with fair-skinned children. In spite of this, S-25(OH) D in dark-skinned children was lower compared with fair-skinned children during both seasons. The dietary intake of vitamin D was positively associated with S-25(OH) D levels.
  
  
  CONCLUSIONS
  Vitamin D status is inadequate in preschool-age children living in northern Sweden, especially in dark-skinned children and during the winter despite vitamin D intakes meeting the recommendations, prompting strategies to improve intake of vitamin D in this population.
authors.affiliation: Department of Clinical Sciences, Pediatrics, Umeå University,Umeå, Sweden. inger.ohlund@pediatri.umu.se
authors.forename: Inger
authors.initials: I
authors.lastname: Öhlund
authors.forename: Sven-Arne
authors.initials: SA
authors.lastname: Silfverdal
authors.forename: Olle
authors.initials: O
authors.lastname: Hernell
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Lind
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012621:Seasons; D012880:Skin Pigmentation; D013472:Sunlight; D013548:Sweden / Q000453:epidemiology; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D