title: Serum 25-hydroxyvitamin D levels in Finnish children aged 2 to 17 years.
abstract: Serum levels of 25-hydroxyvitamin D (25-OHD) in summer and winter were studied in 564 children aged 2-17 years living in the northern, central or southern parts of Finland. The mean levels of 25-OHD were significantly lower in winter (13.3 +/- 10.8 ng/ml) than in summer (27.2 +/- 10.3 ng/ml) in all age groups (p less than 0.001). The mean 25-OHD levels in the northern part of the country did not differ significantly from the others. In both seasons the levels of 25-OHD were lower in the 11-17 year age group than in younger children. In that age group 22.4% of the children had serum levels of 25-OHD below 5 ng/ml (the limit of risk for rickets), compared to 16.8% of children 6-10 years old and 7.5% of children 2-5 years old, but none of the children showed any laboratory evidence of rickets.
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000469:Alkaline Phosphatase / Q000097:blood; D002112:Calcifediol / Q000097:blood*; D002118:Calcium / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005387:Finland; D006801:Humans; D008274:Magnesium / Q000097:blood; D010758:Phosphorus / Q000097:blood; D012279:Rickets / Q000209:etiology; D012306:Risk; D012621:Seasons
chemical_list: D010758:Phosphorus; D000469:Alkaline Phosphatase; D008274:Magnesium; D002112:Calcifediol; D002118:Calcium