title: Reference Intervals of and Relationships among Essential Trace Elements in Whole Blood of Children Aged 0-14 years.
abstract: BACKGROUND
  Essential trace elements are vital to human health. In this study, our aim was to establish reference intervals of and to evaluate relationships among Ca, Fe, Cu, Mg, and Zn for children.
  
  
  METHODS
  We collected blood samples of 3210 children aged 0-14 years from Lu'an, China, and concentrations of the above elements were determined by atomizer absorption spectrophotometer. A nonparametric method was used to establish the reference intervals.
  
  
  RESULTS
  Gender-related differences in concentrations were not statistically significant for the elements, except for Fe. There were strong positive and negative correlations between age and Fe (R = 0.305, P < 0.001), Zn (R = 0.573, P < 0.001); and age and Ca (R = -0.372, P < 0.001), Cu (R = -0.127, P < 0.001), respectively. Correlations between Ca-Mg (r = 0.222~0.384, P < 0.001), Fe-Mg (r = 0.495~0.614, P < 0.001), and Fe-Zn (r = 0.239~0.471, P < 0.001) were the strongest compared with others. In multivariable linear regression, after adjusted for confounding factors, the associations between Zn-Fe and Mg-Fe were the strongest with per concentration quintile increase of Fe caused Zn and Mg increasing by 4.19% (β = 0.041; 95% CI: 0.037, 0.045; P < 0.001) and 3.87% (β = 0.038; 95% CI: 0.036, 0.040; P < 0.001), respectively.
  
  
  CONCLUSIONS
  Gender- and age-based reference intervals of Ca, Fe, Cu, Mg, and Zn for children were established, and correlations between them were quite complex. More works are needed to illuminate these relationships and their impacts on children's health.
authors: Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.
authors: Rongrong
authors: R
authors: Zhai
authors: Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.
authors: Meichun
authors: http://orcid.org/0000-0002-3134-8099
authors: M
authors: Zhang
authors: Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.
authors: Jie
authors: J
authors: Liu
authors: Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.
authors: Hui
authors: H
authors: Guang
authors: Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.
authors: Benzhong
authors: B
authors: Li
authors: Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.
authors: Dong
authors: D
authors: Chen
authors: Clinical Laboratory Center, Lu'an People's Hospital, The Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.
authors: Songtao
authors: S
authors: Zhang
mesh_terms: D000293:Adolescent; D002118:Calcium / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D003300:Copper / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007501:Iron / Q000097:blood*; D008274:Magnesium / Q000097:blood*; D008297:Male; D012016:Reference Values; D013054:Spectrophotometry, Atomic; D014131:Trace Elements / Q000097:blood*; D015032:Zinc / Q000097:blood*
chemical_list: D014131:Trace Elements; D003300:Copper; D007501:Iron; D008274:Magnesium; D015032:Zinc; D002118:Calcium
keywords: blood; children; reference interval; relationship; trace element