title: Selenium level is associated with apoE epsilon4 in rural elderly Chinese.
abstract: OBJECTIVE
  Se is an essential trace element in human nutrition associated with antioxidant activity. Previous studies on predictors of toenail Se or serum Se have mostly concentrated on demographic factors such as age and gender. The present paper examines the association between apoE genotype and Se levels in nail samples in a rural elderly Chinese cohort.
  
  
  METHODS
  Two thousand Chinese aged 65 years and over from four counties in China were enrolled in a cohort to study the association of Se with cognitive decline. Nail samples were collected from each participant and analysed for Se levels. Dietary Se intake was estimated from an FFQ using Se contents measured in food items collected from each village. Blood samples on filter cards were collected and analysed for apoE genotype. Mixed-effect models were constructed with nail Se level as the dependent variable and each village as the random effect, which controlled for the potential confounding effect from correlation in Se measures obtained from participants residing in the same village.
  
  
  RESULTS
  In this elderly Chinese cohort, carriers of the apoE epsilon4 allele had significantly lower Se levels measured in nail samples than non-carriers after adjusting for other significant covariates and controlling for estimated dietary Se intake. There was no significant difference between the two genotypes on estimated Se dietary intake (P = 0.6451).
  
  
  CONCLUSIONS
  Future studies are needed to examine the mechanism underlying the association between the apoE epsilon4 allele and Se levels, including the role of oxidative stress and that of reduced lipid metabolism in the apoE epsilon4 carriers.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202-2872, USA. sgao@iupui.edu
authors.forename: Sujuan
authors.initials: S
authors.lastname: Gao
authors.forename: Yinlong
authors.initials: Y
authors.lastname: Jin
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Hall
authors.forename: Chaoke
authors.initials: C
authors.lastname: Liang
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Unverzagt
authors.forename: Feng
authors.initials: F
authors.lastname: Ma
authors.forename: Yibin
authors.initials: Y
authors.lastname: Cheng
authors.forename: Jianzhao
authors.initials: J
authors.lastname: Shen
authors.forename: Jingxiang
authors.initials: J
authors.lastname: Cao
authors.forename: Janetta
authors.initials: J
authors.lastname: Matesan
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Jianchao
authors.initials: J
authors.lastname: Bian
authors.forename: Hugh C
authors.initials: HC
authors.lastname: Hendrie
authors.forename: Jill R
authors.initials: JR
authors.lastname: Murrell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000502:physiology; D000483:Alleles; D053327:Apolipoprotein E4 / Q000097:blood / Q000235:genetics*; D002681:China; D003072:Cognition Disorders / Q000209:etiology / Q000235:genetics; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D009262:Nails / Q000737:chemistry*; D012307:Risk Factors; D012424:Rural Population; D012643:Selenium / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism*
chemical_list: D053327:Apolipoprotein E4; D012643:Selenium