title: Prospective observational study of isoflavone and the risk of stroke recurrence: potential clinical implications beyond vascular function.
abstract: BACKGROUND
  Whether isoflavone has any effect on recurrent cardiovascular events is unknown.
  
  
  OBJECTIVE
  To investigate the relations between isoflavone intake and the risk of stroke recurrence.
  
  
  METHODS
  We recruited 127 consecutive patients with prior history of atherothrombotic/ hemorrhagic stroke (mean age: 67 ± 11 years, 69% male) and prospectively followed up for a mean duration of 30 months. Stroke recurrence and major adverse cardiovascular events (MACE) were documented. Brachial flow-mediated dilatation (FMD) was measured using high-resolution ultrasound. Isoflavone intake was estimated using a validated food frequency questionnaire.
  
  
  RESULTS
  Median isoflavone intake was 6.9 (range: 2.1 - 14.5) mg/day. Isoflavone intake was independently associated with increased FMD (Pearson R=0.23, p=0.012). At 30 months, there were 10 stroke recurrence and 12 MACE. Kaplan-Meier analysis showed that patients with isoflavone intake higher than median value had significantly longer median stroke recurrence-free survival time (19.0 [range: 10.4 - 27.6] mth versus 5.0 [range: 4.1 - 5.9] mth, p=0.021) and MACE-free survival time (19.0 [range: 10.4 - 27.6] mth versus 4.0 [range: 2.4 - 5.6] mth, p=0.013). Using multivariate cox regression, higher isoflavone intake was an independent predictor for lower risk of stroke recurrence (hazards ratio 0.18 [95%CI: 0.03 - 0.95], risk reduction 82%, p=0.043) and MACE (hazards ratio 0.16 [95%CI: 0.03 - 0.84], risk reduction 84%, p=0.030).
  
  
  CONCLUSIONS
  Higher isoflavone intake in stroke patients was associated with prolonged recurrence-free survival, and reduced risk of stroke recurrence and MACE independent of baseline vascular function. Whether isoflavone may confer clinically significant secondary protection in stroke patients should be further investigated in a randomized controlled trial.
authors.affiliation: School of Public Health, The University of Hong Kong, Hong Kong, China.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Chan
authors.forename: K-K
authors.initials: KK
authors.lastname: Lau
authors.forename: K-H
authors.initials: KH
authors.lastname: Yiu
authors.forename: C-W
authors.initials: CW
authors.lastname: Siu
authors.forename: H-T
authors.initials: HT
authors.lastname: Chan
authors.forename: S-W
authors.initials: SW
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Tam
authors.forename: T-H
authors.initials: TH
authors.lastname: Lam
authors.forename: C-P
authors.initials: CP
authors.lastname: Lau
authors.forename: H-F
authors.initials: HF
authors.lastname: Tse
mesh_terms: D000368:Aged; D001916:Brachial Artery; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D055502:Secondary Prevention; D020521:Stroke / Q000503:physiopathology / Q000517:prevention & control*; D011795:Surveys and Questionnaires; D014463:Ultrasonography
chemical_list: D007529:Isoflavones