Sex specific alterations in autonomic function among patients with irritable bowel syndrome

摘要

Background: Irritable bowel syndrome (IBS) is associated with increased psychological symptoms, earlylife stressors, and alterations in visceral perception and brain responses to noxious visceral stimuli. Theautonomic nervous system (ANS) is a likely mediator for these brain-gut interactions. The few studiesdirectly examining ANS measures have been suggestive of alterations in some IBS patients, but no studiesto date have examined the potentially critical variables of sex differences or response to visceralstimulation.Aims: (1) To test differences in ANS function during rest and during a visceral stressor (reciosigmoidballoon distension) between IBS patients and healthy control subjects. (2) To examine the role of sex on theautonomic responses of IBS patients.Methods: Baseline autonomic measures were evaluated from 130 Rome I positive IBS patients and 55healthy control subjects. Data were also collected from a subset of 46 IBS patients and 16 healthy controlsubjects during a sigmoid balloon distension study. Heart rate variability measures of peak power ratio(PPR) and peak power high frequency (PPHF) were analysed to assess sympathetic balance andparasympathetic response, respectively. Peripheral sympathetic response was measured by skinconductance.Results: IBS patients showed a greater skin conductance response to visceral distension than controls. IBSpatients had higher PPR and lower PPHF across conditions. Male IBS patients had higher skin conductanceand PPR than females and lower PPHF.Conclusions: IBS patients have altered autonomic responsiveness to a visceral stressor, with increasedsympathetic and decreased parasympathetic activity. These differences are predominantly seen in males.