Systematic Reviews
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 28, 2020; 26(20): 2669-2681
Published online May 28, 2020. doi: 10.3748/wjg.v26.i20.2669
Association between non-alcoholic fatty liver disease and obstructive sleep apnea
Ilaria Umbro, Valerio Fabiani, Mario Fabiani, Francesco Angelico, Maria Del Ben
Ilaria Umbro, Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome 00161, Italy
Valerio Fabiani, Department of Neurosciences, Mental Health and Sensory Organs, Sapienza University of Rome, Rome 00123, Italy
Mario Fabiani, Department of Sense Organs, Sapienza University of Rome, Rome 00161, Italy
Francesco Angelico, Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome 00161, Italy
Maria Del Ben, Department of Clinical, Internal, Anesthetic and Cardiovascular Sciences, Sapienza University of Rome, Rome 00161, Italy
Author contributions: Umbro I wrote the paper; Umbro I and Fabiani V collected and analyzed data; Umbro I, Fabiani V, Fabiani M, Angelico F and Del Ben M designed the study, critically reviewed and approved the final version.
Conflict-of-interest statement: Authors declare no conflict of interests for this article.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Ilaria Umbro, MD, Doctor, Research Fellow, Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, Via Alfonso Borelli 50, Rome 00161, Italy. ilaria.umbro@uniroma1.it
Received: January 27, 2020
Peer-review started: January 27, 2020
First decision: March 6, 2020
Revised: March 26, 2020
Accepted: May 15, 2020
Article in press: May 15, 2020
Published online: May 28, 2020
Processing time: 121 Days and 21.8 Hours
Abstract
BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an emerging liver disease and currently the most common cause of incidental abnormal liver tests. The pathogenesis of NAFLD is multifactorial and many mechanisms that cause fatty liver infiltration, inflammation, oxidative stress and progressive fibrosis have been proposed. Obstructive sleep apnea (OSA) may be linked with the pathogenesis and the severity of NAFLD.

AIM

To study the association between NAFLD and OSA considering also the efficacy of continuous positive airway pressure (CPAP) treatment.

METHODS

A PubMed search was conducted using the terms “non-alcoholic fatty liver disease AND (obstructive sleep apnea OR obstructive sleep disorders OR sleep apnea)”. Research was limited to title/abstract of articles published in English in the last 5 years; animal and child studies, case reports, commentaries, letters, editorials and meeting abstracts were not considered. Data were extracted on a standardized data collection table which included: First author, publication year, country, study design, number of patients involved, diagnosis and severity of OSA, diagnosis of NAFLD, patient characteristics, results of the study.

RESULTS

In total, 132 articles were initially retrieved on PubMed search and 77 in the last five years. After removal of irrelevant studies, 13 articles were included in the qualitative analysis. There was a total of 2753 participants across all the studies with a mean age between 42 and 58 years. The proportion of males ranged from 21% to 87.9% and the mean body mass index ranged from 24.0 to 49.9 kg/m2. The results of this review showed an increased prevalence of NAFLD in patients with diagnosis of OSA, even in the absence of coexisting comorbidities such as obesity or metabolic syndrome. Furthermore, the severity of NAFLD is associated with the increase in OSA severity. Effective CPAP treatment, although not always decisive, may stabilize or slow NAFLD progression with benefits on metabolic and cardiovascular functions.

CONCLUSION

In NAFLD patients, although asymptomatic, it is recommended to systematically perform polysomnography in order to early and better treat them before the development of potentially life threatening systemic dysfunctions.

Keywords: Continuous positive air pressure; Non-alcoholic fatty liver disease; Non-alcoholic steatohepatitis; Obstructive sleep apnea; Obstructive sleep disorders; Sleep apnea

Core tip: The development of non-alcoholic fatty liver disease (NAFLD) seems to be closely associated with obstructive sleep apnea (OSA) even in the absence of coexisting comorbidities such as obesity or metabolic syndrome. Furthermore, the severity of NAFLD is associated with the increase in OSA severity. Effective continuous positive airway pressure therapy for OSA may improve serum aminotransferase levels and liver steatosis. As clinicians, our aim should be to screen OSA patients for NAFLD and vice versa those with NAFLD for OSA in order to early and better treat them before the development of potentially life threatening systemic dysfunctions.