title: Cord blood vitamin D and neurocognitive development are nonlinearly related in toddlers.
abstract: BACKGROUND
  Little is known about the relation between vitamin D status in early life and neurodevelopment outcomes.
  
  
  OBJECTIVE
  This study was designed to examine the association of cord blood 25-hydroxyvitamin D [25(OH)D] at birth with neurocognitive development in toddlers.
  
  
  METHODS
  As part of the China-Anhui Birth Cohort Study, 363 mother-infant pairs with complete data were selected. Concentrations of 25(OH)D in cord blood were measured by radioimmunoassay. Mental development index (MDI) and psychomotor development index (PDI) in toddlers were assessed at age 16-18 mo by using the Bayley Scales of Infant Development. The data on maternal sociodemographic characteristics and other confounding factors were also prospectively collected.
  
  
  RESULTS
  Toddlers in the lowest quintile of cord blood 25(OH)D exhibited a deficit of 7.60 (95% CI: -12.4, -2.82; P = 0.002) and 8.04 (95% CI: -12.9, -3.11; P = 0.001) points in the MDI and PDI scores, respectively, compared with the reference category. Unexpectedly, toddlers in the highest quintile of cord blood 25(OH)D also had a significant deficit of 12.3 (95% CI: -17.9, -6.67; P < 0.001) points in PDI scores compared with the reference category.
  
  
  CONCLUSIONS
  This prospective study suggested that there was an inverted-U-shaped relation between neonatal vitamin D status and neurocognitive development in toddlers. Additional studies on the optimal 25(OH)D concentrations in early life are needed.
authors: Department of Maternal, Child, and Adolescent Health, School of Public Health, Anhui Medical University, Hefei, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, China; School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Australia;
authors: Peng
authors: P
authors: Zhu
authors: Department of Maternal, Child, and Adolescent Health, School of Public Health, Anhui Medical University, Hefei, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, China; School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Australia;
authors: Shi-Lu
authors: SL
authors: Tong
authors: Department of Maternal, Child, and Adolescent Health, School of Public Health, Anhui Medical University, Hefei, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, China;
authors: Jia-Hu
authors: JH
authors: Hao
authors: Department of Gynecology and Obstetrics, Hefei First People's Hospital, Hefei, China; and.
authors: Rui-Xue
authors: RX
authors: Tao
authors: Department of Maternal, Child, and Adolescent Health, School of Public Health, Anhui Medical University, Hefei, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, China;
authors: Kun
authors: K
authors: Huang
authors: School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Australia;
authors: Wen-Biao
authors: WB
authors: Hu
authors: Department of Maternal, Child, and Adolescent Health, School of Public Health, Anhui Medical University, Hefei, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, China;
authors: Qi-Fan
authors: QF
authors: Zhou
authors: Department of Gynecology and Obstetrics, Hefei Maternal and Child Health Hospital, Hefei, China.
authors: Xiao-Min
authors: XM
authors: Jiang
authors: Department of Maternal, Child, and Adolescent Health, School of Public Health, Anhui Medical University, Hefei, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, China; fbtao@ahmu.edu.cn.
authors: Fang-Biao
authors: FB
authors: Tao
mesh_terms: D002657:Child Development / Q000187:drug effects*; D002681:China / Q000453:epidemiology; D003071:Cognition / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009752:Nutritional Status; D015995:Prevalence; D011446:Prospective Studies; D011863:Radioimmunoassay; D012959:Socioeconomic Factors; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014807:Vitamin D
keywords: 25-hydroxyvitamin D; cognitive development; cord blood; infant; vitamin D