title: Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and post-stroke dementia: a hospital-based study from northern Iran.
abstract: Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is associated with functional and cognitive outcomes of stroke and plays a key role in preventing neuronal death. This study aimed to answer the following question: does BDNF Val66Met polymorphism prognosticate survival status and risk of post-stroke dementia (PSD)? In a retrospective cohort study, 206 patients with ischemic stroke (IS) entered the study. They were consecutively being admitted to the neurology clinic in Poursina Hospital (northern Iran) from 2012 to 2014. The diagnosis of PSD was based on DSM-5 criteria. The current and the premorbid cognitive statuses of the patients were respectively assessed through the third edition of Addenbrooke's Cognitive Examination and the Informant Questionnaire on Cognitive Decline in the Elderly. BDNF Val66Met gene polymorphism was determined by PCR-RFLP. On average, 48 patients (23.3 %) developed PSD 6 months after IS. Log-rank test showed that the survival rate of at least one Val-allele carriers was significantly lower than that of Met/Met homozygotes (P = 0.0005), and the former developed PSD sooner than the latter (375, 492 days, respectively). Cox model showed that heterozygous carriers of Val/Met were at greater risk of PSD over time (HR 2.280, 95 % CI 1.566-4.106, P = 0.006). However, the risk ratio of patients with PSD among different BDNF genotypes decreased after adjusting demographic, clinical, and vascular risk factors, and was no longer statistically significant (AHR 2.434, 95 % CI 0.597-9.926, P = 0.215). Val-allele carriers or Val/Met genotypes were more quickly diagnosed as having dementia after IS. However, this genetic vulnerability became more destructive when it was added to demographic, clinical, and vascular risk factors.
authors.affiliation: University of Isfahan, Isfahan, Iran.
authors.forename: Sajjad
authors.initials: S
authors.lastname: Rezaei
authors.affiliation: Department of Psychology, University of Isfahan, Isfahan, Iran. asgarika@gmail.com.
authors.forename: Karim
authors.initials: K
authors.lastname: Asgari Mobarake
authors.affiliation: Department of Neurology, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
authors.forename: Alia
authors.initials: A
authors.lastname: Saberi
authors.affiliation: Cellular and Molecular Research Center, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
authors.forename: Parvaneh
authors.initials: P
authors.lastname: Keshavarz
authors.affiliation: Guilan University of Medical Sciences, Rasht, Iran.
authors.forename: Ehsan Kazemnejad
authors.initials: EK
authors.lastname: Leili
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D016009:Chi-Square Distribution; D004252:DNA Mutational Analysis; D003704:Dementia / Q000209:etiology* / Q000235:genetics*; D005260:Female; D005838:Genotype; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008715:Methionine / Q000235:genetics; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D016016:Proportional Hazards Models; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000150:complications* / Q000235:genetics; D014633:Valine / Q000235:genetics
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human; D008715:Methionine; D014633:Valine
keywords: Brain derived neurotrophic factor; Polymorphism; Post-stroke dementia; Prognosis; Risk factors