title: Lower heart rate variability is associated with higher serum high-sensitivity C-reactive protein concentration in healthy individuals aged 46 years or more.
abstract: BACKGROUND
  To test the hypothesis of an association between cardiac autonomic activity evaluated by heart rate variability and systemic inflammatory markers such as C-reactive protein, we studied the correlation of the indices of heart rate variability relative to serum high-sensitivity C-reactive protein (hs-CRP) in a healthy Brazilian population.
  
  
  METHODS
  Four hundred twenty-one healthy individuals aged 15-82 years (mean 40.4 years), 184 men (43.7%) and 237 women (56.3%) were enrolled between July 1998 and July 2001. The relationship between the log-transformed indices of the heart rate variability and the serum concentration of hs-CRP were analyzed stratified by age tertile using the Spearman correlation coefficient and multiple linear regression.
  
  
  RESULTS
  The log standard deviation of all normal sinus RR intervals over 24 h (SDNN) (r = -0.801; p = 0.024) was independently correlated with log hs-CRP in the individuals with age in the oldest tertile (> or = 46 years). In addition, the body mass index (BMI) was independently correlated with hs-CRP in all of the age groups.
  
  
  CONCLUSIONS
  In the healthy subjects aged 46 years or more the lower heart rate variability correlated with higher concentration of hs-CRP.
authors.affiliation: Heart Institute (InCor), University of São Paulo Medical School, General Outpatient Clinics, Av. Dr. Enéas de Carvalho Aguiar, 44 05403-000 São Paulo SP, Brazil. grafernando@incor.usp.br
authors.forename: Fernando
authors.initials: F
authors.lastname: Araújo
authors.forename: Ivana
authors.initials: I
authors.lastname: Antelmi
authors.forename: Alexandre C
authors.initials: AC
authors.lastname: Pereira
authors.forename: Maria do Rosário D O
authors.initials: Mdo R
authors.lastname: Latorre
authors.forename: Cesar José
authors.initials: CJ
authors.lastname: Grupi
authors.forename: José E
authors.initials: JE
authors.lastname: Krieger
authors.forename: Alfredo José
authors.initials: AJ
authors.lastname: Mansur
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil / Q000453:epidemiology; D002097:C-Reactive Protein / Q000378:metabolism*; D015331:Cohort Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018709:Statistics, Nonparametric
chemical_list: D002097:C-Reactive Protein