title: Vitamin D status among 4-month-old infants in New England: a prospective cohort study.
abstract: BACKGROUND
  Concerns over vitamin D deficiency in infants and children recently prompted the American Academy of Pediatrics to recommend increased supplementation. Few studies have examined vitamin D status in the same infants over time. Also, while many researchers label "breastfeeding" as a risk factor for vitamin D deficiency, few differentiate between any breastfeeding, exclusive breastfeeding, and supplemented or unsupplemented breastfeeders.
  
  
  OBJECTIVE
  To determine predictors of 25(OH)D deficiency at 4 months in a group of children previously tested at birth.
  
  
  METHODS
  We enrolled newborns from 2005 to 2007 at an urban Boston hospital. Maternal and infant blood samples were collected within 72 hours of birth. At 4 months, we obtained a second infant blood sample.
  
  
  RESULTS
  At 4 months, 11.9% of the 177 infants were vitamin D deficient compared to 37.5% at birth (25(OH)D <20 ng/mL). Median 25(OH)D was 35.2 ng/mL (range, 5-100.8; 95% confidence interval [CI], 32.8-37.6). At 4 months, 40% of unsupplemented infants were deficient. Lack of supplementation was significantly associated with increased risk of deficiency (adjusted odds ratio [AOR], 19.3; 95% CI, 4.80-77.2). Being outside at least 10 minutes a day, once per week, was protective (AOR, 0.12; 95% CI, 0.02-0.66), as was increasing gestational age (AOR, 0.36; 95% CI, 0.19-0.69). In 48.4% of patients, physicians failed to prescribe vitamin D at 2 months.
  
  
  CONCLUSIONS
  Despite inconsistent supplementation, a smaller proportion of infants were vitamin D deficient at 4 months than at birth. While supplemented breastfed infants were not at risk of deficiency, unsupplemented exclusively breastfed infants were at high risk of severe deficiency.
authors.affiliation: Division of General Pediatrics, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts 02118, USA. anne.merewood@bmc.org
authors.forename: Anne
authors.initials: A
authors.lastname: Merewood
authors.forename: Supriya D
authors.initials: SD
authors.lastname: Mehta
authors.forename: Xena
authors.initials: X
authors.lastname: Grossman
authors.forename: Tai C
authors.initials: TC
authors.lastname: Chen
authors.forename: Jeff
authors.initials: J
authors.lastname: Mathieu
authors.forename: Michael F
authors.initials: MF
authors.lastname: Holick
authors.forename: Howard
authors.initials: H
authors.lastname: Bauchner
mesh_terms: D001942:Breast Feeding; D019587:Dietary Supplements; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009511:New England; D009749:Nutrition Surveys; D011446:Prospective Studies; D012307:Risk Factors; D012621:Seasons; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000453:epidemiology* / Q000517:prevention & control
chemical_list: D014807:Vitamin D