title: A secondary analysis of racial differences in periodic leg movements in sleep and ferritin in hemodialysis patients.
abstract: OBJECTIVE
  Hemodialysis (HD) is associated with restless legs syndrome (RLS) and periodic leg movements in sleep (PLMS), but the mechanisms underlying these relationships remain unclear. African-American HD patients have been reported previously to have a reduced likelihood of RLS. Alterations in iron metabolism, known to be a risk factor for idiopathic forms of RLS, could represent the basis for these racial differences.
  
  
  METHODS
  In secondary data analyses from a previously published study, we examined raw and log-transformed values for plasma ferritin and polysomnographically recorded PLMS in Caucasian and African-American HD patients.
  
  
  RESULTS
  African-American (n=36) HD patients had higher ferritin and lower PLMS than Caucasians (n=10). However, within the African-American population, ferritin levels were unrelated to PLMS.
  
  
  CONCLUSIONS
  These results are compatible with previously reported racial differences in RLS to the extent that PLMS were less common in the African-American population. However, they suggest that if a differential genetic vulnerability underlies those racial differences, it may not manifest as a deficiency in iron metabolism, at least within the constraints of the marker of iron stores used here (e.g. serum ferritin) and in the specific population studied (hemodialysis). Future studies with larger, more representative samples of African-Americans and Caucasians will be required to replicate such differences.
authors.affiliation: Department of Psychiatry, Kangwon National University College of Medicine, Chunchon, Kangwon-do, South Korea.
authors.forename: Jung Hie
authors.initials: JH
authors.lastname: Lee
authors.forename: Kathy P
authors.initials: KP
authors.lastname: Parker
authors.forename: Fari P
authors.initials: FP
authors.lastname: Ansari
authors.forename: Donald L
authors.initials: DL
authors.lastname: Bliwise
mesh_terms: D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D005260:Female; D005293:Ferritins / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020189:Nocturnal Myoclonus Syndrome / Q000097:blood* / Q000208:ethnology*; D017286:Polysomnography; D015995:Prevalence; D006435:Renal Dialysis; D051437:Renal Insufficiency / Q000097:blood / Q000208:ethnology / Q000628:therapy; D044465:White People / Q000706:statistics & numerical data*
chemical_list: D005293:Ferritins