title: Reduced heart rate variability is associated with increased arterial stiffness in youth with type 1 diabetes: the SEARCH CVD study.
abstract: OBJECTIVE
  Reduced heart rate variability (HRV) and increased arterial stiffness (AS) are both present in youth with type 1 diabetes. However, it is unclear whether they are associated and whether their association is independent of cardiovascular disease (CVD) risk factors.
  
  
  METHODS
  The SEARCH Cardiovascular Disease (SEARCH CVD) study explored the cross-sectional relationships between HRV and several measures of AS in youth with (n = 344) and without (n = 171) type 1 diabetes. The SphygmoCor device (AtCor Medical, Sydney, Australia) was used to measure HRV using SD of normal R-R interval (SDNN), as well as AS, using pulse wave velocity in the carotid to femoral segment (PWV-trunk) and augmentation index adjusted to a heart rate of 75 bpm (AIx75). Brachial distensibility (BrachD), another index of AS, was measured with a DynaPulse instrument (Pulse Metric, San Diego, CA). Multiple linear regression analyses explored the associations between HRV and each of the three AS measures, after adjusting for demographic characteristics and traditional CVD risk factors (blood pressure, lipids, obesity, microalbuminuria, and smoking) separately, for youth with and without type 1 diabetes.
  
  
  RESULTS
  Among youth with type 1 diabetes, lower SDNN was associated with peripheral AS (lower BrachD, P = 0.01; r(2) = 0.30) and central AS (higher PVW-trunk, P < 0.0001; r(2) = 0.37; and higher AIx75, P = 0.007; r(2) = 0.08). These associations were attenuated with adjustment for CVD risk factors, but remained statistically significant for BrachD and PWV-trunk. While a similar association between HRV and BrachD was present in control youth, lower HRV was not associated with increased central AS or with AIx75.
  
  
  CONCLUSIONS
  Longitudinal studies are needed to understand the pathways responsible for these associations.
authors: Department of Epidemiology, Colorado School of Public Health, Aurora, Colorado, USA.
authors: Mamta
authors: M
authors: Jaiswal
authors: Elaine M
authors: EM
authors: Urbina
authors: R Paul
authors: RP
authors: Wadwa
authors: Jennifer W
authors: JW
authors: Talton
authors: Ralph B
authors: RB
authors: D'Agostino
authors: Richard F
authors: RF
authors: Hamman
authors: Tasha E
authors: TE
authors: Fingerlin
authors: Stephen R
authors: SR
authors: Daniels
authors: Santica M
authors: SM
authors: Marcovina
authors: Lawrence M
authors: LM
authors: Dolan
authors: Dana
authors: D
authors: Dabelea
mesh_terms: D000293:Adolescent; D001341:Autonomic Nervous System / Q000502:physiology; D001916:Brachial Artery / Q000503:physiopathology; D002318:Cardiovascular Diseases / Q000209:etiology; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D063177:Pulse Wave Analysis; D012307:Risk Factors; D059289:Vascular Stiffness; D055815:Young Adult