Abstract and Introduction
Background Sleep disturbances are common, and perhaps are even more prevalent in irritable bowel syndrome (IBS).
Aims To determine the effect of measured sleep on IBS symptoms the following day, IBS-specific quality of life (IBS-QOL) and non-GI pain symptoms.
Methods IBS patients' sleep patterns were compared to healthy individuals via wrist-mounted actigraphy over 7 days. Daily bowel pain logs (severity, distress; 10-point Likert) stool pattern (Bristol scale) and supporting symptoms (e.g. bloating, urgency; 5-point Likert) were kept. Validated measures, including the GI Symptom Rating Scale-IBS, Visceral Sensitivity Index, Pittsburgh Sleep Quality Index and the IBS-Quality of Life were collected. Mediation analysis explored the relationship between sleep, mood and bowel symptoms.
Results Fifty subjects (38.6 ± 1.0 years old, 44 female; 24 IBS and 26 healthy controls) completed sleep monitoring. IBS patients slept more hours per day (7.7 ± 0.2 vs. 7.1 ± 0.1, P = 0.008), but felt less well-rested. IBS patients demonstrated more waking episodes during sleep (waking episodes; 12.1 vs. 9.3, P < 0.001). Waking episodes predicted worse abdominal pain (P ≤ 0.01) and GI distress (P < 0.001), but not bowel pattern or accessory IBS symptoms (P > 0.3 for each). Waking episodes negatively correlated with general- and IBS-specific QOL in IBS (r = −0.58 and −0.52, P < 0.001 for each). Disturbed sleep effects on abdominal pain were partially explained by mood as an intermediate.
Conclusions Sleep disturbances are more common in irritable bowel syndrome, and correlate with IBS-related pain, distress and poorer irritable bowel syndrome-related quality of life. Disturbed sleep effects extend beyond the bowel, leading to worse mood and greater somatic pain in patients with the irritable bowel syndrome.
Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) disorder, affecting as many as 15% of US adults. IBS is characterised by the hallmark symptoms of abdominal pain or discomfort and altered bowel habits, resulting in poor health-related quality of life (HRQOL). IBS patients commonly endorse both affective symptoms (e.g. depression and anxiety) and somatic pain symptoms without structural explanation, such as back pain and headache.
Several lifestyle factors can modify symptom perception in the IBS patient, including diet and exercise.[3–6] Of particular interest to this study was the potential role of sleep in IBS symptom perception. Disordered sleep is quite common, with as many as 70 million Americans, or one-third of US adults having insomnia symptoms.[7,8] Sleep disturbances appear to be even more common in IBS, affecting as many as 50% of diagnosed individuals.[9,10] While prototypical IBS symptoms can potentially have a deleterious effect on a restorative sleep pattern, recent evidence suggests that sleep disruption may directly enhance visceral hypersensitivity and GI symptoms. For example, gastroesophageal reflux disease (GERD) patients experimentally deprived of sleep have more severe oesophageal symptoms when exposed to acid stimulation protocols. Specific to functional GI disorders, a recent study in women (n = 24) with IBS showed that self-reported sleep disturbances were associated with abdominal pain, anxiety and fatigue the next day. Furthermore, since affective disorders (anxiety and depression) are common in IBS, and that sleep disturbances are a hallmark feature of these mood disorders,[14,15] psychiatric comorbidity may play an important role in understanding the effect of sleep on IBS symptoms.
Despite previous observations that poor sleep is more common in IBS, little is known about the impact of disturbed sleep on individual IBS symptoms. Which specific derangements in sleep pattern may lead to expression of IBS symptoms is poorly understood. Furthermore, we are not aware of any study which has examined the influence of sleep on mood and extraintestinal symptoms, both critical factors to the symptom severity and HRQOL in the IBS patient. We speculate that sleep disturbances in IBS patients result in a generalised hypersensitivity to pain, both visceral and somatic, via alterations in central nervous system responses to peripheral pain signals within brain regions known to modulate the affective and cognitive responses to pain, such as the homoeostatic afferent processing network. We further hypothesised that mood disturbances, also represented within much of the same brain neurocircuity,[17,18] would render IBS patients particularly susceptible to the effects of disordered sleep on pain perception.
This study prospectively measured sleep quality and collected subjective sleep reports to determine the relationship of objective and subjective sleep measures on IBS symptoms and IBS-specific HRQOL. We also sought to examine whether any effect of sleep on pain is specific to visceral discomfort, or more generally to non-GI symptoms as well. Finally, we aimed to explore the role of mood as a potential mediator between sleep and pain symptoms.
Aliment Pharmacol Ther. 2016;44(3):246-258. © 2016 Blackwell Publishing