title: High prevalence of maternal vitamin D deficiency in preterm births in northeast China, Shenyang.
abstract: BACKGROUND
  Maternal vitamin D deficiency has been associated with a number of fetal and neonatal health problems. Preterm birth is one of the most detrimental, and the role of maternal vitamin D deficiency in preterm births has not been universally acknowledged. There had been limited epidemiological studies of vitamin D deficiency on the Chinese population.
  
  
  METHODS
  1103 women delivered in Shengjing Hospital, China Medical University from January 1(st), 2012 to January 1(st), 2013. Finally, 821 mother-newborn pairs which contained 143 mother-newborn pairs who were preterm delivery were recruited for analysis.
  
  
  RESULTS
  There was significant difference between spring and summer (P<0.0001) as well as spring and autumn (P<0.01). Compared to those in summer and autumn, the 25 (OH) D level was significantly lower in winter (summer vs winter P<0.0001, autumn vs winter P<0.0001). Maternal vitamin D level showed obvious variation with months and seasons, with higher level in summer months and lower level in winter months. There were significant difference between the vitamin D level of the very preterm group and the mildly preterm groups (P<0.01), as well as the very preterm group and the in-term groups (P<0.001). Prevalence of Vitamin D deficiency occurred in 63.04% of pregnant women in very preterm group, compared with 36.61% in in-term group.
  
  
  CONCLUSIONS
  Vitamin D nutritional status of pregnant women and their newborns in Shenyang were relatively good compared to cities in similar latitudes. Vitamin D deficiency was most severe in late spring and least in summer. Severe preterm births before 31 weeks of gestation was associated with maternal vitamin D deficiency.
authors.affiliation: Department of Pediatric Orthopedic, Shengjing Hospital of China Medical University China.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhu
authors.affiliation: Department of Pediatric Orthopedic, Shengjing Hospital of China Medical University China.
authors.forename: Tian-Jing
authors.initials: TJ
authors.lastname: Liu
authors.affiliation: Laboratory of Metabolic Disease Research and Drug Development, China Medical University China.
authors.forename: Xin
authors.initials: X
authors.lastname: Ge
authors.affiliation: Department of Clinical Nutrition, Shengjing Hospital of China Medical University China.
authors.forename: Juan
authors.initials: J
authors.lastname: Kong
authors.affiliation: Department of Pediatric Orthopedic, Shengjing Hospital of China Medical University China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Zhang
authors.affiliation: Department of Pediatric Orthopedic, Shengjing Hospital of China Medical University China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D002681:China / Q000453:epidemiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology*; D015995:Prevalence; D012621:Seasons; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications* / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D014807:Vitamin D
keywords: Serum 25-hydroxyvitamin D; pregnancy; preterm; season; vitamin D deficiency