title: Association of alpha1a-adrenergic receptor polymorphism and blood pressure phenotypes in the Brazilian population.
abstract: BACKGROUND
  The alpha1A-adrenergic receptor (alpha1A-AR) regulates the cardiac and peripheral vascular system through sympathetic activation. Due to its important role in the regulation of vascular tone and blood pressure, we aimed to investigate the association between the Arg347Cys polymorphism in the alpha1A-AR gene and blood pressure phenotypes, in a large sample of Brazilians from an urban population.
  
  
  METHODS
  A total of 1568 individuals were randomly selected from the general population of the Vitória City metropolitan area. Genetic analysis of the Arg347Cys polymorphism was conducted by polymerase chain reaction/restriction fragment length polymorphism. We have compared cardiovascular risk variables and genotypes using ANOVA, and Chi-square test for univariate comparisons and logistic regression for multivariate comparisons.
  
  
  RESULTS
  Association analysis indicated a significant difference between genotype groups with respect to diastolic blood pressure (p = 0.04), but not systolic blood pressure (p = 0.12). In addition, presence of the Cys/Cys genotype was marginally associated with hypertension in our population (p = 0.06). Significant interaction effects were observed between the studied genetic variant, age and physical activity. Presence of the Cys/Cys genotype was associated with hypertension only in individuals with regular physical activity (odds ratio = 1.86; p = 0.03) or younger than 45 years (odds ratio = 1.27; p = 0.04).
  
  
  CONCLUSIONS
  Physical activity and age may potentially play a role by disclosing the effects of the Cys allele on blood pressure. According to our data it is possible that the Arg347Cys polymorphism can be used as a biomarker to disease risk in a selected group of individuals.
authors.affiliation: Heart Institute/InCor, University of São Paulo Medical School, Brazil. sroig@ioc.fiocruz.br
authors.forename: Silvia R
authors.initials: SR
authors.lastname: Freitas
authors.forename: Alexandre C
authors.initials: AC
authors.lastname: Pereira
authors.forename: Marcilene S
authors.initials: MS
authors.lastname: Floriano
authors.forename: José G
authors.initials: JG
authors.lastname: Mill
authors.forename: José E
authors.initials: JE
authors.lastname: Krieger
mesh_terms: D000328:Adult; D000367:Age Factors; D001794:Blood Pressure / Q000235:genetics*; D001938:Brazil; D002318:Cardiovascular Diseases / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D018340:Receptors, Adrenergic, alpha-1 / Q000235:genetics*; D012307:Risk Factors; D014505:Urban Population
chemical_list: C547713:ADRA1A protein, human; D018340:Receptors, Adrenergic, alpha-1