Cardiac autonomic regulation in response to a mixed meal is impaired in obese children and adolescents: the role played by insulin resistance.
BACKGROUND
Obesity in children/adolescents has been associated with subtle cardiac abnormalities, including myocardial dysfunction and cardiac autonomic dysregulation at rest, both likely responsible for a higher mortality in adulthood. Food intake induces remarkable adjustments of cardiovascular autonomic activity in healthy subjects.


OBJECTIVE
The objective of the study was to evaluate in obese children/adolescents meal-induced cardiac autonomic response and the role played by insulin resistance.


METHODS
Sixty-eight obese and 30 matched normal-weight children/adolescents underwent blood sampling and cardiovascular autonomic analysis while recumbent and 20 minutes after a mixed meal ingestion. Spectrum analysis of the R-R interval and systolic blood pressure (SBP) variability provided the indices of sympathetic [low frequency (LFRR)] and vagal [high frequency (HFRR)] modulation of the sinoatrial node and the low frequency component of SBP. The homeostasis model assessment of insulin resistance served to separate insulin resistant (n = 35) from non insulin resistant (n = 33) obese children/adolescents.


RESULTS
At baseline, C-reactive protein, the LFRR to HFRR ratio, SBP, and low frequency oscillatory component of SBP variability in obese children/adolescents were significantly (P < .05) greater than in referent subjects, whereas high-density lipoprotein cholesterol and HFRR were lower; meal-induced increase in the LFRR to HFRR ratio was significantly less than in controls and exaggeratedly scanty (or opposite) among insulin resistant subjects. The homeostasis model assessment of insulin resistance index strongly and inversely correlated (r = -0.871; P < .001) with meal-induced changes in the LFRR to HFRR ratio among obese subjects.


CONCLUSIONS
Autonomic modulation of the heart was impaired after eating in obese children/adolescents. This abnormality was exaggerated among insulin resistant subjects and strongly correlated with the degree of insulin resistance.
Division of Internal Medicine (D.C., G.P.), Division of Endocrinology (K.E., A.D.B.), and Department of Pediatrics (S.P., L.P., E.M.d.G.), Second University of Naples, 80131 Naples, Italy; Department of Internal Medicine (R.F.), Humanitas Clinical and Research Center, Rozzano, BIOMETRA Department, University of Milan, 20122 Milan, Italy; and Division of Cardiology (D.T.), University of Catanzaro, 88100 Catanzaro, Italy.
Domenico
D
Cozzolino
Katherine
K
Esposito
Giuseppe
G
Palmiero
Annamaria
A
De Bellis
Raffaello
R
Furlan
Silverio
S
Perrotta
Laura
L
Perrone
Daniele
D
Torella
Emanuele
E
Miraglia del Giudice
D000293:Adolescent; D001342:Autonomic Nervous System Diseases / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D001835:Body Weight; D002648:Child; D004435:Eating / Q000502:physiology*; D005260:Female; D006321:Heart / Q000294:innervation* / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D009765:Obesity / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D012849:Sinoatrial Node / Q000294:innervation / Q000502:physiology; D013564:Sympathetic Nervous System / Q000503:physiopathology; D014630:Vagus Nerve / Q000503:physiopathology; D014636:Valsalva Maneuver / Q000502:physiology