Autonomic nervous system activity is independently associated with the risk of shift in the non-dipper blood pressure pattern.
An insufficient decrease in nocturnal blood pressure (BP) is a known factor in cardiovascular mortality. We aimed to determine whether autonomic nervous system (ANS) activity and its change over 2 years were associated with a shift to non-dipper status, independently of initial BP, in a general elderly population. From participants in the PROOF study, 600 subjects untreated for hypertension were selected (age at baseline: 65 years, men: 41.5%). Dipper/non-dipper status was defined using repeated measures of 24-h ambulatory BP at baseline and 2 years later. ANS activity was evaluated on the basis of 24-h heart rate variability at both examinations. Among the 454 dipper subjects at baseline, 26.2% became non-dippers. Multivariate analysis showed that a +1 between-subject s.d. increase in the very low frequency at baseline was associated with a decreased odds ratio for the shift to non-dipper status 2 years later (OR=0.61 [0.41-0.91], P=0.02). The within-subject change between the two measurements of day and night systolic BP and day diastolic BP also contributed significantly to the risk of shift to non-dipper status. Our results suggest that impaired ANS activity precedes an insufficient decrease in nocturnal BP independent of hypertension status.
Dauphinot
Virginie
V
Neurology Unit D, University Medical Hospital, University of Lyon, Lyon, France. d_virginie@hotmail.com
Gosse
Philippe
P
Kossovsky
Michel P
MP
Schott
Anne-Marie
AM
Rouch
Isabelle
I
Pichot
Vincent
V
Gaspoz
Jean-Michel
JM
Roche
Frédéric
F
Barthelemy
Jean-Claude
JC
D000368:Aged; D001341:Autonomic Nervous System / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000503:physiopathology*; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D012307:Risk Factors