title: Spontaneous baroreflex sensitivity in (pre)adolescents.
abstract: OBJECTIVE
  To present normal spontaneous baroreflex sensitivity (BRS) values and investigate the influence of posture, sex, age, pubertal stage, body mass index (BMI), and physical activity level on BRS in (pre)adolescents. BRS is a sensitive measure of both sympathetic and parasympathetic cardiovascular regulation that may help detect early subclinical autonomic dysfunction.
  
  
  METHODS
  A cross-sectional cohort study in a large sample of 10-13-year-old Dutch (pre)adolescents from the general population.
  
  
  METHODS
  Short-term spontaneous BRS was determined non-invasively by Portapres in both the supine and standing position. BRS was calculated by power spectral analysis using the discrete Fourier method (frequency band 0.07-0.14 Hz). Univariate statistical methods and multiple regression analyses were applied.
  
  
  RESULTS
  BRS in a standing position was lower than in a supine position (9.0 +/- 4.9 versus 15.3 +/- 9.1 ms/mmHg; t = 27.8, P < 0.001). Girls had lower BRS values than boys in both postures (supine 14.3 +/- 8.7 versus 16.4 +/- 9.4 ms/mmHg, beta = 0.12, P < 0.001; standing 8.4 +/- 4.4 versus 9.5 +/- 5.4 ms/mmHg, beta = 0.08, P = 0.012), independent of age, pubertal stage, BMI, and physical activity. Lower limits (P2.5) for normal BRS values in supine and standing positions were for girls 3.6 and 2.2 ms/mmHg and for boys 3.9 and 2.5 ms/mmHg, respectively. BRS declined with age in the standing position (beta = -0.13, P < 0.001). In obese (pre)adolescents, BMI was negatively associated with BRS during standing (Kendall's tau = -0.26, P = 0.010).
  
  
  CONCLUSIONS
  The BRS of (pre)adolescents was negatively related to female sex, age, and obesity. A reduced BRS in obese (pre)adolescents might be a candidate predictor of future cardiovascular health, and therefore warrants further exploration.
authors.affiliation: Graduate School of Behavioral and Cognitive Neurosciences, Department of Psychiatry, University of Maastricht, Maastricht, The Netherlands. a.dietrich@med.umcg.nl
authors.forename: Andrea
authors.initials: A
authors.lastname: Dietrich
authors.forename: Harriëtte
authors.initials: H
authors.lastname: Riese
authors.forename: Arie M
authors.initials: AM
authors.lastname: van Roon
authors.forename: Klaartje
authors.initials: K
authors.lastname: van Engelen
authors.forename: Johan
authors.initials: J
authors.lastname: Ormel
authors.forename: Jan
authors.initials: J
authors.lastname: Neeleman
authors.forename: Judith G M
authors.initials: JG
authors.lastname: Rosmalen
mesh_terms: D000293:Adolescent; D017704:Baroreflex / Q000502:physiology*; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D015999:Multivariate Analysis; D011187:Posture; D012737:Sex Factors