Functional GI Disorders Linked to Excessive Daytime Sleepiness
—This study of 2906 individuals from across China assessed the relationship between excessive daytime sleepiness and gastrointestinal disorders.
A recent study of nearly 3000 people from the Systematic Investigation of Gastrointestinal Diseases in China (SILC) revealed a correlation between gastrointestinal (GI) disorders and excessive daytime sleepiness (EDS).1
Lead author Dr. Sicheng Wu and colleagues at the Second Military Medical Hospital, in Shanghai, China published their paper entitled, “Association Between Excessive Daytime Sleepiness and Functional Gastrointestinal Disorders: A Population-based Study in China” in the Journal of Neurogastroenterology and Motility. In this study, the authors sought to determine the connections between EDS and GI disorders in China.
Individuals with EDS are unable to remain awake and alert during the regular waking hours of the day, which can be problematic and stressful. EDS has been linked to GI disorders previously; however, more systematic studies of the relationship between various GI disorders and EDS are still needed.2
“EDS is a common sleep-related symptom in China… However, the relationship between EDS and functional gastrointestinal disorders (FGIDs) in the general population has not been systematically studied, especially in China,” the authors note.
Dr. Wu and colleagues aimed to obtain a more complete understanding of this relationship in the Chinese population, where prevalence of EDS is higher than in the United States (22.2% vs 8.7%).3,4
Study design
This was an analysis of a sub-sample of 20% of participants (3600 subjects) from the SILC who were administered the 36-item Short Form Health Survey and Epworth Sleepiness Scale (ESS). Of those included, 2906 (80.72%) participants completed the survey. As part of the standard SILC, these subjects also participated in a number of other questionnaires regarding GI issues and sleep disturbances.
The SILC investigators collected information on the gender, age, marital status, education level, family income, occupation, cigarette and alcohol consumption, exercise, body mass index (BMI), as well as family and personal medical history of GI diseases, as well as several other health characteristics.
GI disorders and EDS
Of the 2906 participants who completed the survey, 644 (22.2%) had EDS. Overweight and obese patients were more likely than those with a normal BMI to have EDS, as were participants with a family history of asthma. In addition, those with education levels of either primary school or lower or university or higher were more likely to have EDS than participants who completed secondary school.
The authors found no significant correlation between gender, age, region marital status, occupation, family income, smoke status, alcohol consumption, or exercise status and EDS diagnosis.
Patients with gallbladder dysfunction scored highest on the ESS, while those with functional diarrhea scored the lowest. After adjusting for multiple variables, the authors found that ulcer-like dyspepsia, diarrhea-predominant IBS, alternating IBS, functional constipation, and GERD predicted EDS diagnosis. No significant correlations were observed between EDS and other GI disorders, including dysmotility-like dyspepsia, aerophagia, constipation-predominant IBS, functional abdominal bloating, functional diarrhea, and gallbladder dysfunction.
The risk of EDS increased with the number of FGIDs in this study. Participants with one FGID were more likely to have EDS than those with none, and the FGID number was directly correlated with increased EDS risk (0 < 1 < 2 < 3 FGIDs).
This study was performed across 5 key regions in China, and achieved a high response rate, which offers a fair representation of the general population while avoiding responder-bias. The authors also highlight the variety of diagnostic tests used to differentiate subtypes of irritable bowel syndrome (IBS) and functional dyspepsia (FD) as a strength of the study, offering more nuanced insights into the role of FGIDs on EDS risk.
There are limitations to this study as well, however, “since anxiety and depression were all self-reported in our study, the association between FD (defined as Rome III criteria) and EDS needs further studies, in which possible confounders like psychological distress and obesity should be better controlled,” the authors state. Further, the cross-sectional design of this study does not offer a causal understanding of the phenomena revealed, and the subjective nature of the ESS may result in an overestimation of EDS prevalence in this cohort.
The authors discuss a number of potential mechanisms by which obesity, asthma, and GI disorders may influence EDS risk, such as sleep apnea, and dysregulation of the gut-brain axis. However, they suggest that further studies are needed to elucidate the pathologic contributions to EDS. It may also be important to consider EDS and FGID comorbidity as a risk factor for other diseases, such as Parkinson’s disease, which is often preceded by non-motor symptoms including sleep disruption and GI dysfunction.5
“The relationships between FGIDs and sleep problems are complex, and coexistence of FGIDs may be associated with more severe sleep problems… Physicians should pay attention to the sleep status of patients who are troubled with more than one kind of FGIDs,” Dr. Wu and colleagues conclude.
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