title: Maternal and child's vitamin D supplement use and vitamin D level in relation to childhood lung function: the KOALA Birth Cohort Study.
abstract: BACKGROUND
  Vitamin D is associated with lung function in adults, but its relation with childhood lung function is still unclear.
  
  
  OBJECTIVE
  To investigate whether prenatal and postnatal vitamin D supplementation and plasma level is associated with childhood lung function.
  
  
  METHODS
  In the KOALA Birth Cohort Study, children's lung function (n=436) was measured at age 6-7 years by means of spirometry and presented as forced expiratory volume in 1 s (FEV1) z scores and forced vital capacity z scores. The mother and child's 25-hydroxyvitamin D plasma level was determined around 36 weeks of pregnancy and at age 2 years. Vitamin D supplement intake during pregnancy was defined based on the amount of vitamin D in supplements, and trimester and duration of use. Data on child's vitamin D supplement use were collected through questionnaires at ages 1, 2 and 6-7 years.
  
  
  RESULTS
  25-Hydroxyvitamin D level and vitamin D supplement use in childhood were not associated with lung function. Maternal use of vitamin D at ≤10 μg/day (adjusted beta (AdjB -0.37; 95% CI -0.69 to -0.05)), vitamin D containing multivitamin use in the second and/or third trimester (AdjB -0.26; 95% CI -0.49 to -0.03), and use for two trimesters (AdjB -0.25; 95% CI -0.49 to -0.02) were associated with a significantly lower FEV1 z score compared with no supplements. Maternal use of vitamin D at ≥10 μg/day and use in the first or all trimesters was not associated with significantly lower lung function levels.
  
  
  CONCLUSIONS
  The authors found no association between 25-hydroxyvitamin D levels, vitamin D supplementation in childhood or recommended vitamin D dosage of ≥10 μg/day during pregnancy and lung function in children aged 6-7 years.
authors.affiliation: Department of Epidemiology, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
authors.forename: Elleke
authors.initials: E
authors.lastname: Cremers
authors.forename: Carel
authors.initials: C
authors.lastname: Thijs
authors.forename: John
authors.initials: J
authors.lastname: Penders
authors.forename: Eugene
authors.initials: E
authors.lastname: Jansen
authors.forename: Monique
authors.initials: M
authors.lastname: Mommers
mesh_terms: D002648:Child; D002664:Child Nutritional Physiological Phenomena / Q000502:physiology; D015331:Cohort Studies; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008168:Lung / Q000187:drug effects* / Q000196:embryology / Q000502:physiology; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D039401:Prenatal Nutritional Physiological Phenomena / Q000502:physiology; D014797:Vital Capacity / Q000187:drug effects; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood / Q000494:pharmacology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D