title: Metabolic syndrome burden in apparently healthy adolescents is adversely associated with cardiac autonomic modulation--Penn State Children Cohort.
abstract: BACKGROUND
  Reduced cardiac autonomic modulation (CAM) has been associated with metabolic syndrome (MetS) in adults. However, the association between MetS component cluster and CAM has not been examined in adolescents.
  
  
  METHODS
  We conducted a cross-sectional analysis using data from the Penn State Child Cohort follow-up examination. CAM was assessed by heart rate variability (HRV) analysis of 39-h RR intervals, including frequency (high frequency, HF; low frequency, LF; and LF/HF ratio) and time (SDNN, standard deviation of all RR intervals; RMSSD, square root of the mean of the sum of the squares of differences between adjacent RR intervals; and HR, heart rate) domain variables. To assess the MetS burden, we used continuous MetS score (cMetS)--sum of the age and sex-adjusted standardized residual (Z-score) of five established MetS components. Linear mixed-effect models were used to analyze the association between cMetS and CAM in the entire population and stratified by gender.
  
  
  RESULTS
  After adjusting for age, sex, and race, cMetS was significantly associated with reduced HRV and higher HR. With 1 standard deviation increase in cMetS, there was a significant decrease in HF (-0.10 (SE = 0.02)), LF (-0.07 (SE = 0.01)), SDNN (-1.97 (SE = 0.50)), and RMSSD (-1.70 (SE = 0.72)), and increase in LF/HF (0.08 (SE = 0.02)) and HR (1.40 (SE = 0.26)). All cMetS components, with the exception of high-density lipoprotein (HDL), were associated with significantly decreased HRV and increased HR. High blood pressure (MAP) and triglyceride (TG) levels were also associated with an increase in LF/HF and decrease in RMSSD. An increase in high-density lipoprotein was only associated with higher LF and SDNN. Moreover, cMetS and HRV associations were more pronounced in males than in females. The associations between HRV and. MAP, TG, and HDL were more pronounced in females.
  
  
  CONCLUSIONS
  cMetS score is associated with lower HRV, suggesting an adverse impact on CAM, even in apparently healthy adolescents.
authors: Department of Public Health Sciences Penn State University College of Medicine, Hershey, PA, 17033. Electronic address: srodrigu@phs.psu.edu.
authors: Sol M
authors: SM
authors: Rodríguez-Colón
authors: Department of Public Health Sciences Penn State University College of Medicine, Hershey, PA, 17033. Electronic address: fhe@phs.psu.edu.
authors: Fan
authors: F
authors: He
authors: Sleep Research &Treatment Center, Department of Psychiatry, Penn State University College of Medicine, Hershey, PA, 17033. Electronic address: ebixler@hmc.psu.edu.
authors: Edward O
authors: EO
authors: Bixler
authors: Sleep Research &Treatment Center, Department of Psychiatry, Penn State University College of Medicine, Hershey, PA, 17033. Electronic address: jfernandezmendoza@hmc.psu.edu.
authors: Julio
authors: J
authors: Fernandez-Mendoza
authors: Sleep Research &Treatment Center, Department of Psychiatry, Penn State University College of Medicine, Hershey, PA, 17033. Electronic address: avgontzas@hmc.psu.edu.
authors: Alexandros N
authors: AN
authors: Vgontzas
authors: Sleep Research &Treatment Center, Department of Psychiatry, Penn State University College of Medicine, Hershey, PA, 17033. Electronic address: scalhoun@hmc.psu.edu.
authors: Susan
authors: S
authors: Calhoun
authors: School of Public Health, Shanghai Jiao Tong University, Shanghai, China. Electronic address: zhengzj@sjtu.edu.cn.
authors: Zhi-Jie
authors: ZJ
authors: Zheng
authors: Department of Public Health Sciences Penn State University College of Medicine, Hershey, PA, 17033. Electronic address: dliao@psu.edu.
authors: Duanping
authors: D
authors: Liao
mesh_terms: D000293:Adolescent; D001341:Autonomic Nervous System / Q000503:physiopathology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000503:physiopathology*; D010414:Pennsylvania; D012044:Regression Analysis
keywords: Cardiovascular diseases; Central obesity; Hypertension; Insulin resistance; Metabolic syndrome