Abstract MP91: Abdominal Obesity, Independent of General Obesity, is Associated With Reduced Circadian Pattern of Cardiac Autonomic Modulation in Adolescents
Introduction: Reduced cardiac autonomic modulation (CAM) has been associated with metabolic syndrome and higher CVD risk in adults. However, the association between abdominal obesity and the circadian pattern of CAM has not been examined in adolescents.
Hypothesis: We hypothesize that abdominal obesity is adversely associated with the circadian pattern of cardiac autonomic modulation in adolescents.
Methods: We used data from the Penn State Child Cohort follow-up examination (N=421). Cardiac autonomic modulation was assessed by heart rate variability (HRV) analysis of 24-hour RR intervals, including frequency and time domain variables. We used 3-parameters from a cosine periodic regression to quantify the 24-hour HRV circadian pattern, namely, the mean levels of HRV indices (M), the amplitude of the oscillation (Â), and the timing of the highest oscillation (θ). A dual-energy x-ray absorptiometry was used to assess abdominal obesity, as android/gynoid fat ratio, visceral (VAT) and subcutaneous (SAT) fat areas. BMI percentile was used to assess general obesity. Random-effect meta-analysis regression was used to associate the 3 HRV circadian parameters with abdominal obesity measures, adjusting for BMI percentile, age, sex, and race.
Results: The mean age was 17 years (SD=2.3). The mean BMI percentile was 66 (SD=28). The prevalence of obesity was 16%. After adjusting for the above mentioned covariables, abdominal obesity was significantly associated with a lower M of HRV, and starting to affect the Â and θ by shifting its circadian pattern away from the normal individuals, as illustrated in the figure below contrasting adolescents in the highest quartile of VAT and those in the lower 3 quartiles of VAT. A consistent pattern of associations were observed across various measures of HRV and various measures of abdominal obesity.
Conclusion: Abdominal obesity, independent of general obesity, has started to adversely affect the circadian pattern of cardiac autonomic modulation in otherwise healthy adolescents.
Author Disclosures: S.M. Rodríguez-Colón: None. A. Berg: None. Y. Imamura Kawasawa: None. A. Salzberg: None. E.O. Bixler: None. J. Fernandez-Mendoza: None. A.N. Vgontzas: None. D. Liao: None.
- © 2015 by American Heart Association, Inc.