title: Maternal vitamin D status in pregnancy and risk of lower respiratory tract infections, wheezing, and asthma in offspring.
abstract: BACKGROUND
  Adequate vitamin D status in mothers during pregnancy may influence the health status of the child later in life. We assessed whether maternal circulating 25-hydroxyvitamin D (25[OH]D) concentrations in pregnancy are associated with risk of lower respiratory tract infections, wheezing, and asthma in the offspring.
  
  
  METHODS
  Data were obtained from 1724 children of the INfancia y Medio Ambiente (INMA) Project, a population-based birth cohort study. Maternal circulating 25(OH)D concentrations were measured in pregnancy (mean gestational age = 12.6 [SD = 2.5] weeks). When the child was age 1 year, parents were asked if their child had a physician-confirmed history of lower respiratory tract infections or a history of wheezing. The questions about wheezing were repeated annually thereafter. Asthma was defined as parental report of doctor diagnosis of asthma or receiving treatment at the age of 4-6 years or wheezing since the age of 4 years.
  
  
  RESULTS
  The median maternal circulating 25(OH)D concentration in pregnancy was 29.5 ng/mL (interquartile range, 22.5-37.1 ng/mL). After multivariable adjustment, there was a trend for an independent association between higher levels of maternal circulating 25(OH)D levels in pregnancy and decreased odds of lower respiratory tract infections in offspring (for cohort- and season-specific quartile Q4 vs. Q1, odds ratio = 0.67 [95% confidence interval = 0.50-0.90]; test for trend, P = 0.016). We found no association between 25(OH)D levels in pregnancy and risk of wheezing at age 1 year or 4 years, or asthma at age 4-6 years.
  
  
  CONCLUSIONS
  Higher maternal circulating 25(OH)D concentrations in pregnancy were independently associated with lower risk of lower respiratory tract infections in offspring in the first year of life but not with wheezing or asthma in childhood.
authors.affiliation: Center for Research in Environmental Epidemiology, Barcelona, Catalonia, Spain. emorales1@creal.cat
authors.forename: Eva
authors.initials: E
authors.lastname: Morales
authors.forename: Isabelle
authors.initials: I
authors.lastname: Romieu
authors.forename: Stefano
authors.initials: S
authors.lastname: Guerra
authors.forename: Ferrán
authors.initials: F
authors.lastname: Ballester
authors.forename: Marisa
authors.initials: M
authors.lastname: Rebagliato
authors.forename: Jesús
authors.initials: J
authors.lastname: Vioque
authors.forename: Adonina
authors.initials: A
authors.lastname: Tardón
authors.forename: Cristina
authors.initials: C
authors.lastname: Rodriguez Delhi
authors.forename: Leonor
authors.initials: L
authors.lastname: Arranz
authors.forename: Maties
authors.initials: M
authors.lastname: Torrent
authors.forename: Mercedes
authors.initials: M
authors.lastname: Espada
authors.forename: Mikel
authors.initials: M
authors.lastname: Basterrechea
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D012135:Respiratory Sounds / Q000209:etiology*; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000209:etiology*; D013030:Spain / Q000453:epidemiology; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D014807:Vitamin D