Association between obstructive sleep apnea and non-alcoholic fatty liver disease: a systematic review and meta-analysis

Abstract

The relationship between obstructive sleep apnea (OSA) and non-alcoholic fatty liver disease (NAFLD) has been an issue of great concern. The primary purpose of this study was to determine the influence of OSA on the levels of liver enzymes including alanine transaminase (ALT) and aspartate transaminase (AST). The secondary purpose was to estimate the effect of OSA on the histological lesions of NAFLD, such as steatosis, lobular inflammation, ballooning degeneration, fibrosis, as well as NAFLD activity score (NAS). A systematic literature review using PubMed, Cochrane Library, Embase, and Ovid technologies from January 2007 to April 2017 was performed, and 9 studies (2272 participants) that met the selection criteria were evaluated. The present study demonstrated that OSA was related to ALT levels, but no significant correlation was found with AST levels. The subgroup analysis showed that the severity of OSA was associated with ALT levels, not with AST levels. The meta-regression analysis showed that age, sex, homeostasis model assessment, diabetes mellitus, body mass index, and waist circumference did not have a significant effect on the levels of ALT and AST. OSA was also found to be significantly correlated with steatosis, lobular inflammation, ballooning degeneration, and fibrosis, but was not correlated with NAS. OSA was independently related to the development and progression of NAFLD in terms of liver enzyme level and histological alterations. Future studies should investigate the possible relevant mechanisms, thereby guiding the exploration of potential therapeutic implications to prevent the progression of disease.

Intrahepatic Expression of Fatty Acid Translocase CD36 Is Increased in Obstructive Sleep Apnea

“…An increasing number of clinical studies point out to a potential link between obstructive sleep apnea (OSA), a respiratory disorder featured by nocturnal intermittent hypoxia (IH) and sleep fragmentation, and NAFLD (15)(16)(17)(18). To highlight, both OSA and NAFLD are especially prevalent among obese individuals and, more interestingly, the severity of nocturnal IH positively correlates with histological features of NASH in OSA patients (19).…”

Hypoxia and Non-alcoholic Fatty Liver Disease

“…Notably, a study has demonstrated that OSA patients were three times more likely to have NASH compared with subjects without OSA (41). Moreover, clinical evidence suggests a direct relationship between OSA and NAFLD severity (42,45). Interestingly, low O 2 saturation has been proposed as an important NAFLD risk factor in OSA patients: the lower the O 2 saturation, the higher the NAFLD severity (37,46).…”

MECHANISMS OF ENDOCRINOLOGY: Mechanisms of disease: the endocrinology of obstructive sleep apnoea

“…In addition, several other neurohormonal mechanisms are involved in the links between OSA and T2D, which are summarised in Fig. 3 (30,39,51,65,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113).…”

“…One plausible mechanism in patients with pre-diabetes or diabetes is autonomic neuropathy, which might impact on UA innervation (6), ventilatory drive and central respiratory responses to hypercapnia (109,110). In addition, T2D is associated with reduced pulmonary volumes and functions compared to healthy individuals which could affect UA stability (111,112,113,114,115,116,117,118,119,120,121) and diffusion capacity for carbon monoxide (112,113,122,123). The impact of T2D on the lungs seems to be related to the severity of hyperglycaemia independently of obesity and smoking (123), which raises the possibility that improvements in glycaemic control might have a favourable impact on OSA.…”