title: Cardiac autonomic control and the effects of age, race, and sex: the CARDIA study.
abstract: BACKGROUND
  Stratification variables of age, race, and sex figure prominently in the assessment of cardiovascular disease risk. Similarly, cardiac autonomic regulation, measured by RR interval variability (RRV), is associated with risk. The relationship among these variables is unclear.
  
  
  METHODS
  We examined the cross-sectional relationship between RRV and age, race, and sex in 757 subjects from the NHLBI-funded Coronary Artery Disease in Young Adults (CARDIA) Study.
  
  
  RESULTS
  Age was a significant determinant of RRV, despite the narrow range (33-47): participants aged 33-39 years had had greater levels of HF power, LF power, and standard deviation (SD) of RR intervals than did those aged 40-47 years. There was no age effect for the LF/HF ratio. Compared to whites, blacks had lower levels of LF power, SD, and lower LF/HF. Blacks and whites did not differ in HF power. Finally, compared to men, women had lower levels of LF power, SD, and LF/HF but did not differ in HF power.
  
  
  CONCLUSIONS
  Data from the CARDIA study suggest that in adults in the 33-47 year age range, indices of RRV were greater in younger compared to older subjects, in men compared to women and in whites compared to blacks. These findings are broadly consistent with those of other large studies examining relationships between RRV and age, sex, and race. However, patterns of associations between RRV and these stratification variables are not entirely consistent with an underlying autonomic physiology linked to cardioprotection.
authors.affiliation: Behavioral Medicine Program, Columbia University Medical Center, New York NY 10032, USA. rps7@columbia.edu <rps7@columbia.edu>
authors.forename: Richard P
authors.initials: RP
authors.lastname: Sloan
authors.forename: Mei-Hua
authors.initials: MH
authors.lastname: Huang
authors.forename: Heather
authors.initials: H
authors.lastname: McCreath
authors.forename: Stephen
authors.initials: S
authors.lastname: Sidney
authors.forename: Kiang
authors.initials: K
authors.lastname: Liu
authors.forename: O
authors.initials: O
authors.lastname: Dale Williams
authors.forename: Teresa
authors.initials: T
authors.lastname: Seeman
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000502:physiology*; D044383:Black People; D001794:Blood Pressure / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D012016:Reference Values; D012494:Sampling Studies; D012727:Sex Characteristics; D044465:White People