title: Vitamin D Intake and Status in 6-Year-Old Icelandic Children Followed up from Infancy.
abstract: High serum 25-hydroxyvitamin D (25(OH)D) levels have been observed in infants in Nordic countries, likely due to vitamin D supplement use. Internationally, little is known about tracking vitamin D status from infancy to childhood. Following up 1-year-old infants in our national longitudinal cohort, our aims were to study vitamin D intake and status in healthy 6-year-old Icelandic children (n = 139) and to track vitamin D status from one year of age. At six years, the mean 25(OH)D level was 56.5 nmol/L (SD 17.9) and 64% of children were vitamin D sufficient (25(OH)D ≥ 50 nmol/L). A logistic regression model adjusted for gender and breastfeeding showed that higher total vitamin D intake (Odds ratio (OR) = 1.27, 95% confidence interval (CI) = 1.08-1.49), blood samples collected in summer (OR = 8.88, 95% CI = 1.83-43.23) or autumn (OR = 5.64, 95% CI = 1.16-27.32) compared to winter/spring, and 25(OH)D at age one (OR = 1.02, 95% CI = 1.002-1.04) were independently associated with vitamin D sufficiency at age six. The correlation between 25(OH)D at age one and six was 0.34 (p = 0.003). Our findings suggest that vitamin D status in infancy, current vitamin D intake and season are predictors of vitamin D status in early school age children. Our finding of vitamin D status tracking from infancy to childhood provides motivation for further studies on tracking and its clinical significance.
authors: Unit for Nutrition Research, Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland and Landspitali University Hospital, Reykjavik 101, Iceland. bth50@hi.is.
authors: Birna
authors: B
authors: Thorisdottir
authors: Unit for Nutrition Research, Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland and Landspitali University Hospital, Reykjavik 101, Iceland. ingigun@hi.is.
authors: Ingibjorg
authors: I
authors: Gunnarsdottir
authors: Unit for Nutrition Research, Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland and Landspitali University Hospital, Reykjavik 101, Iceland. laufey@hi.is.
authors: Laufey
authors: L
authors: Steingrimsdottir
authors: Children's Hospital, Landspitali University Hospital, Reykjavik 101, Iceland. gesturip@landspitali.is.
authors: Gestur I
authors: GI
authors: Palsson
authors: Unit for Nutrition Research, Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland and Landspitali University Hospital, Reykjavik 101, Iceland. beb@hi.is.
authors: Bryndis E
authors: BE
authors: Birgisdottir
authors: Unit for Nutrition Research, Faculty of Food Science and Nutrition, School of Health Sciences, University of Iceland and Landspitali University Hospital, Reykjavik 101, Iceland. ingathor@hi.is.
authors: Inga
authors: I
authors: Thorsdottir
mesh_terms: D002648:Child; D000067576:Child Health; D002675:Child, Preschool; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D007223:Infant; D000068104:Infant Health; D016015:Logistic Models; D008297:Male; D009752:Nutritional Status; D012621:Seasons; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D014815:Vitamins / Q000008:administration & dosage / Q000097:blood
chemical_list: D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D; child; dietary supplements; seasons; tracking; vitamin D