Prof Nicholas Talley

Sleep disturbance is an independent risk factor for IBS and related conditions, according to new Australian research that has begun to unravel the complicated association between the two conditions.

The finding, from a survey of more than 1300 people, will open up new lines of research and potential treatments for the collection of gut disorders, neurogastroenterologist and study author Professor Nicholas Talley from the University of Newcastle tells the limbic.

While the presence of sleep disturbance in people with chronic gut syndromes like IBS is common and now well-established, explains Professor Talley, research into it’s role in gastrointestinal disorders is confounded by the equally high rates of psychological distress, including depression, anxiety and somatisation, reported by people with IBS.

“So the question is then: is the finding that sleep disturbances are more common in these disorders related to the psychological distress these people have or in fact are these really potentially independent of the psychological distress?”

Surveying a subset of randomly selected participants who had responded to the 2015 Digestive Health and Wellbeing postal survey, Professor Talley and colleagues used validated questionnaires to assess rates of IBS, sleep disturbance and psychological disturbance in the community.

Among the group, functional GI disorders were common with IBS and functional dyspepsia (FD) affecting 10% and 17%, respectively.

Overall, 41.8% of people with an FGID (IBS and/or FD) reported any sleep disturbance at least most of the time at a significantly higher rate than controls who did not have IBS and/or FD (32.2%, P = 0.003).

In IBS, one third reported not feeling rested upon waking and not getting enough sleep, respectively, whereas approximately one quarter of people with IBS reported problems with initiating as well as problems maintaining sleep at least most of the time. And rates were similar in FD

A greater sleep disturbance score – a tally based on the the number of disturbed sleeping types participants identified as having – was a significant predictor of meting IBS even after controlling for age, sex and psychological distress.

“ I think that finding is pretty exciting – it says that sleep might, perhaps, even be a cause of these disorders – but we need to work that through, there’s a lot more for us to study,” adds Professor Talley.

But while the findings were consistent across both diarrhoea-predominant and mixed pattern IBS, constipation-dominant IBS remained an outlier.

“We found that if you were constipated, interestingly, that didn’t seem to be linked to sleep disturbance independent of psychological distress. I guess that suggests they’re probably different conditions; that the constipation group has a different mechanism or set of mechanisms.

“We’ve thought that for quite some time and it’s certainly consistent with some other data about mechanisms in IBS.”

Clinical implications

While work to find a possible mechanism for the association between poor sleep and IBS continues, Professor Talley did identify some immediate clinical implications including screening for sleep disturbance.

“That could be a couple of very simple questions, I think if patients are sleeping poorly trying to improve sleep hygiene may help reduce symptoms – that’s speculative but it certainly makes sense.”

He said encouraging people to set a routine bedtime, establishing a ritual before bed that doesn’t disturb their sleep, for example avoiding looking at screens before sleep, and encouraging people to keep a sleep diary so they can track IBS symptoms against sleep patterns can be helpful techniques that are worth considering.

Meanwhile the team will begin investigating various mechanisms, including the immune pathway, that might explain the increased risk for IBS that comes with disturbed sleep.

“We know that poor sleep is related to poorer immune function and we know from other work in IBS and related conditions that the immune system is abnormally ramped up in these conditions so we’re wondering if this link might be related to an immune mechanism. If that’s the case we can interfere and we can potentially do something about it.

We’re also looking at clock genes – the genes that regulate our sleep/wake cycle – to see whether that cycle is abnormal in these conditions and whether that’s related to the clock genes being disturbed. It’s very exciting and there may be some real solutions for IBS in the future.”

The study was published in Alimentary Pharmacology and Therapeutics