Lower heart rate variability is associated with higher serum high-sensitivity C-reactive protein concentration in healthy individuals aged 46 years or more

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-CR-P) 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 (>= 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 con-elated with higher concentration of lis-CRP. (c) 2005 Elsevier Ireland Ltd. All rights reserved.