title: Increased rates of white matter hyperintensities in late-onset bipolar disorder.
abstract: OBJECTIVE
  Magnetic resonance imaging (MRI) studies have reported an increased frequency of white matter hyperintensities (WMH) in association with late-onset (LO) depression, and this has supported the notion that vascular-related mechanisms may be implicated in the pathophysiology of LO mood disorders. Recent clinical studies have also suggested a link between LO bipolar disorder (LO-BD) and cerebrovascular risk factors, but this has been little investigated with neuroimaging techniques. In order to ascertain whether there could be a specific association between WMH and LO-BD, we directly compared WMH rates between LO-BD subjects (illness onset >or= 60 years), early-onset BD subjects (EO-BD, illness onset <60 years), and elderly healthy volunteers.
  
  
  METHODS
  T2-weighted MRI data were acquired in LO-BD subjects (n = 10, age = 73.60 +/- 4.09), EO-BD patients (n = 49, age = 67.78 +/- 4.44), and healthy subjects (n = 24, age = 69.00 +/- 7.22). WMH rates were assessed using the Scheltens scale.
  
  
  RESULTS
  There was a greater prevalence of WMH in LO-BD patients relative to the two other groups in the deep parietal region (p = 0.018) and basal ganglia (p < 0.045). When between-group comparisons of mean WMH scores were conducted taking account of age differences (ANCOVA), there were more severe scores in LO-BD patients relative to the two other groups in deep frontal and parietal regions, as well as in the putamen (p < 0.05).
  
  
  CONCLUSIONS
  Our results provide empirical support to the proposed link between vascular risk factors and LO-BD. If extended in future studies with larger samples, these findings may help to clarify the pathophysiological distinctions between bipolar disorder emerging at early and late stages of life.
authors.affiliation: Department of Psychiatry, University of São Paulo Medical School, São Paulo, Brazil. jhatsu@gmail.com
authors.forename: Jaqueline Hatsuko
authors.initials: JH
authors.lastname: Tamashiro
authors.forename: Stevin
authors.initials: S
authors.lastname: Zung
authors.forename: Marcus Vinicius
authors.initials: MV
authors.lastname: Zanetti
authors.forename: Cláudio Campi
authors.initials: CC
authors.lastname: de Castro
authors.forename: Homero
authors.initials: H
authors.lastname: Vallada
authors.forename: Geraldo F
authors.initials: GF
authors.lastname: Busatto
authors.forename: Tânia Correa
authors.initials: TC
authors.lastname: de Toledo Ferraz Alves
mesh_terms: D017668:Age of Onset; D000368:Aged; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000145:classification / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*