title: Low vitamin D deficiency in Irish toddlers despite northerly latitude and a high prevalence of inadequate intakes.
abstract: OBJECTIVE
  While reports of inadequate vitamin D intakes among young children are widespread, data on the prevalence of vitamin D deficiency are inconsistent. We aimed to quantify vitamin D intake and serum 25-hydroxyvitamin D [25(OH)D] concentrations in children aged 2 years in the prospective Cork BASELINE Birth Cohort Study.
  
  
  METHODS
  Serum 25(OH)D was analysed using UPLC-MS/MS in 741 children living in Cork, Ireland (51°N). Two-day weighed food diaries were collected in 467 children, and 294 provided both a blood sample and a food diary.
  
  
  RESULTS
  Mean (SD) 25(OH)D concentrations were 63.4 (20.4) nmol/L [winter: 54.5 (19.9), summer: 71.2 (17.5)]. The prevalence of vitamin D deficiency (<30 nmol/L) was 4.6, and 26.7% were <50 nmol/L [45.2% during winter (November-April) and 10.4% in summer (May-October)]. With a mean (SD) vitamin D intake of 3.5 (3.1) µg/day, 96% had intakes below 10 µg/day, the current IOM estimated average requirement and the SACN safe intake value for this age group. After adjustment for season, vitamin D intake (µg/day) was associated with higher 25(OH)D concentrations [adjusted estimate (95% CI) 2.5 (1.9, 3.1) nmol/L]. Children who did not consume vitamin D-fortified foods or supplements had very low vitamin D intakes (1.2 (0.9) µg/day), and during winter, 12 and 77% were <30 and <50 nmol/L, respectively, compared with 6 and 44% of fortified food consumers.
  
  
  CONCLUSIONS
  There was a high prevalence of low vitamin D status during winter, especially among children who did not consume fortified foods or nutritional supplements. Our data indicate the need for dietary strategies to increase vitamin D intakes in this age group. This report provides further evidence that DRVs for vitamin D should be based on experimental data in specific population groups and indicates the need for dose-response RCTs in young children.
authors.affiliation: Cork Centre for Vitamin D and Nutrition Research, School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.|The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland.
authors.forename: Carol
authors.initials: C
authors.lastname: Ní Chaoimh
authors.affiliation: Cork Centre for Vitamin D and Nutrition Research, School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.|The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland.
authors.forename: Elaine K
authors.initials: EK
authors.lastname: McCarthy
authors.affiliation: The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland.|Department of Paediatrics and Child Health, University College Cork, Cork, Ireland.
authors.forename: Jonathan O'B
authors.initials: JO
authors.lastname: Hourihane
authors.affiliation: The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland.|Department of Obstetrics and Gynaecology, University College Cork, Cork, Ireland.
authors.forename: Louise C
authors.initials: LC
authors.lastname: Kenny
authors.affiliation: Department of Clinical Medicine, Trinity College, Dublin, Ireland.|Department of Paediatric Dermatology, Our Lady's Children's Hospital, Dublin, Ireland.|National Children's Research Centre, Dublin, Ireland.
authors.forename: Alan D
authors.initials: AD
authors.lastname: Irvine
authors.affiliation: The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland.|Department of Paediatrics and Child Health, University College Cork, Cork, Ireland.
authors.forename: Deirdre M
authors.initials: DM
authors.lastname: Murray
authors.affiliation: Cork Centre for Vitamin D and Nutrition Research, School of Food and Nutritional Sciences, University College Cork, Cork, Ireland. m.kiely@ucc.ie.|The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland. m.kiely@ucc.ie.
authors.forename: Mairead E
authors.initials: ME
authors.lastname: Kiely
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood; D002112:Calcifediol / Q000097:blood; D002664:Child Nutritional Physiological Phenomena / Q000208:ethnology; D002675:Child, Preschool; D015331:Cohort Studies; D004032:Diet / Q000009:adverse effects* / Q000208:ethnology; D015930:Diet Records; D019587:Dietary Supplements; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D009752:Nutritional Status / Q000208:ethnology; D015995:Prevalence; D011446:Prospective Studies; D012621:Seasons; D014807:Vitamin D / Q000008:administration & dosage*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*
chemical_list: D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol
keywords: 25-Hydroxyvitamin D; Fortified foods; Supplements; Vitamin D intake; Young children