Heart Rate Variability and Somatization in Adolescents With Irritable Bowel Syndrome

BACKGROUND/AIMS: Changes in autonomic regulation and psychological distress play an important role in the pathobiology of irritable bowel syndrome (IBS). The aim of the current study is to evaluate the autonomic function and to link it to the levels of somatization in adolescents with IBS. METHODS: We enrolled 30 adolescents with various types of IBS and 35 healthy controls. Time and frequency domain indexes of heart rate variability (HRV) were measured in supine (baseline) and standing (orthostasis) positions using short-term electrocardiographic recordings. The somatic symptoms index was assessed with the modified Screening for Somatoform Symptoms questionnaire. RESULTS: Adolescents with IBS showed no differences of HRV parameters in the supine position compared to healthy control. In orthostasis, a decrease in the standard deviation of normal RR intervals as well as main spectral index total power (TP) were observed. The reduction of TP was attributed to the reduced activities of the high- and low frequency components. Increased somatic symptoms index in IBS patients negatively correlated with TP in orthostasis (r = –0.485, P = 0.007). A subgroup analysis revealed that adolescents with IBS with TP values either < 2500 msec(2) or > 5500 msec(2) in the supine position demonstrated significantly reduced activity of the low frequency component. CONCLUSIONS: Adolescents with IBS showed signs of autonomic dysfunction only during the orthostatic test, which were associated with increased somatization scores. Further research is needed to establish the links between emotional wellbeing and autonomic function in this population.