title: Vitamin D deficiency in pediatric patients with cystic fibrosis: associated risk factors in the northern United States.
abstract: OBJECTIVE
  Cystic fibrosis (CF) is associated with vitamin D deficiency, which can lead to adverse effects including recurrent pulmonary infections and osteoporosis. We longitudinally investigated calcifediol or 25-hydroxyvitamin D (25(OH)D) levels for our pediatric patients with CF based on the time of year as well as vitamin D supplementation dosing ranges for these patients at our CF center.
  
  
  METHODS
  We retrospectively evaluated vitamin D deficiency in our pediatric CF center for 2 years (baseline and annually) while evaluating 25(OH)D serum changes based on vitamin D supplementation, seasonality, patient age, and other factors associated with CF.
  
  
  RESULTS
  Vitamin D supplementation was noted to be higher than current Cystic Fibrosis Foundation dosing recommendations, and no patient experienced vitamin D toxicity. Seasonality was a strong indicator of 25(OH)D levels, especially during summer or fall. Significantly fewer patients with initially low 25(OH)D levels maintained low levels at the conclusion of the study, suggesting benefit. Older patient age and higher supplemental dosing correlated with significantly lower 25(OH)D levels.
  
  
  CONCLUSIONS
  This study suggests that targeted intervention among pediatric patients with CF living in northern latitudes of the United States, especially older children, is needed to prevent vitamin D deficiency.
authors.affiliation: From the Departments of Psychology, Pediatric Pulmonology, and Pediatric Gastroenterology, Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City.
authors.forename: Amy Hughes
authors.initials: AH
authors.lastname: Lansing
authors.affiliation: From the Departments of Psychology, Pediatric Pulmonology, and Pediatric Gastroenterology, Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City.
authors.forename: Catherine
authors.initials: C
authors.lastname: McDonald
authors.affiliation: From the Departments of Psychology, Pediatric Pulmonology, and Pediatric Gastroenterology, Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City.
authors.forename: Raza A
authors.initials: RA
authors.lastname: Patel
authors.affiliation: From the Departments of Psychology, Pediatric Pulmonology, and Pediatric Gastroenterology, Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Meihls
authors.affiliation: From the Departments of Psychology, Pediatric Pulmonology, and Pediatric Gastroenterology, Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City.
authors.forename: Kody
authors.initials: K
authors.lastname: Crowell
authors.affiliation: From the Departments of Psychology, Pediatric Pulmonology, and Pediatric Gastroenterology, Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City.
authors.forename: Barbara
authors.initials: B
authors.lastname: Chatfield
authors.affiliation: From the Departments of Psychology, Pediatric Pulmonology, and Pediatric Gastroenterology, Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City.
authors.forename: John F
authors.initials: JF
authors.lastname: Pohl
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D002112:Calcifediol / Q000097:blood / Q000172:deficiency; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D016896:Treatment Outcome; D014481:United States; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D014815:Vitamins / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002112:Calcifediol