Prevalence and risk factors of non-alcoholic fatty liver disease among Korean adults

Background and Aim: Differences in the prevalence of non‐alcoholic fatty liver disease (NAFLD) between Eastern and Western populations are primarily attributable to differences in definitions and biased population selection. Thus, the aim of the present study was to accurately determine the actual prevalence of NAFLD by sonography and to characterize the risk factors for NAFLD. Methods: The present cross‐sectional study was performed with data obtained from 6648 subjects, all of whom were older than 20 years of age (3530 men and 3118 women). The term ‘non‐drinker’ was applied to men who consumed less than 30 g alcohol/day and to women who consumed less than 20 g alcohol/day. Non‐alcoholic fatty liver disease was defined as a sonographically detected fatty liver in the absence of viral hepatitis in a non‐drinker. Results: Of the 1613 subjects who were diagnosed with sonographic fatty liver, 1240 were non‐drinkers and had no viral hepatitis. Overall, the unadjusted and age‐adjusted prevalences of NAFLD were 18.7% (23% in men, 13.7% in women) and 16.1% (21.6% in men, 11.2% in women), respectively. Multivariate analysis revealed that several risk factors were profoundly associated with the prevalence of NAFLD, including obesity, insulin resistance, hyperlipidemia and hyperglycemia in both genders, as well as age, menopausal status and estrogen medication in women only. Conclusions: These results demonstrate that the prevalence of NAFLD in Korean adults, according to sonographic surveys, is comparable to that seen in more developed countries. From the perspective of increasing obesity, the high prevalence rates noted in the study may herald an increased burden of chronic liver disease in the Korean population.     

成人非酒精性脂肪肝与代谢综合征关系的研究

目的探讨非酒精性脂肪肝(NAFLD)和代谢综合征(MS)的关系。方法对2006年10～12月长沙市某企业3744例20岁以上职工进行问卷调查、体格检查、空腹血糖、血脂、丙氨酸转氨酶、血尿酸检测以及肝脏B超检查。结果(1)NAFLD患病率23.5%,MS患病率22.8%,两病的共患病率12.6%。(2)MS、中心性肥胖、血压升高、空腹血糖升高、高三酰甘油、低高密度脂蛋白胆固醇各组NAFLD患病风险分别是对照组的13.4～22.2倍。(3)以NAFLD取代MS5个组分中的任何一个后,与原诊断定义相比有较高一致性(Kappa值0.53～0.89,P<0.01)。(4)采用多因素Logistic回归分析,调整了性别、年龄和多项代谢成分的影响后,NAFLD与MS独立相关(OR2.342,95%CI:1.825～3.007;P<0.01)。结论该人群中1/5以上患有NAFLD和MS,且NAFLD与MS密切相关;NAFLD可纳入MS的组成成分。     

An update on non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in Asia

Introduction: Non-alcoholic fatty liver disease (NAFLD) has become the most overwhelming liver disease in Asia. In consideration of its increasing medical and economic impact on Asian people, it is time for us to review the update data in Asian countries and formulate strategies to cope with this emerging health problem in Asia. Moreover, growing data indicates that NAFLD may be a systemic disease, not just confined to liver-specific morbidity and mortality, but also associated with several extra-hepatic manifestations, such as cardiovascular diseases, chronic renal diseases, and malignancy. As the co-occurrence of NAFLD and viral hepatitis is common in Asia, issues related to the impact of NAFLD on the clinical outcomes and management of viral hepatitis remain to be elucidated.

Areas covered: In this article, a narrative review was conducted, searching for literature from PubMed, Ovid MEDLINE, and the Cochrane Library database till August 2016. Studies relevant to the emerging data of NAFLD in Asia, including the diagnosis, risk factors, the assessment and management of Asian NAFLD patients were examined and discussed.

Expert commentary: Collaboration in Asian countries to develop an effective and practical measurement to assess the severity of NAFLD is urgently required.     

Significant correlations between severe fatty liver and risk factors for metabolic syndrome

BACKGROUND AND AIM: It is known that ultrasonography (US) cannot differentiate between non-alcoholic fatty liver disease (NAFLD) and steatohepatitis. However, US can accurately estimate the severity of the steatosis. The clinical significance of severe hepatic fatty change by US has not been explored. The aim of this study was to investigate the relationship between the severity of the fatty liver, classified by US, and the degree of metabolic disorders with insulin resistance. METHODS: In 16 486 Taiwanese patients, severity of fatty change on US was classified as follows: group A (n = 6950), absence of fatty change; group B (n = 8694), mild; and group C (n = 842), severe fatty liver change. Biometabolic parameters included body mass index (BMI), blood pressure (BP), fasting plasma glucose, triglycerides, cholesterol, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and serum creatinine. Nominal logistic regression analysis was used to estimate the odds ratio for different degrees of fatty liver. RESULTS: The frequencies of obesity, hypertension, glucose intolerance and hypertriglyceridemia were all significantly higher in group C than in group A or B (P < 0.0001), and the mean values of BMI, BP, fasting glucose, triglyceride and ALT were also higher in group C (P < 0.0001). High BMI (>or=30 kg/m(2)) appears to be the most important factor for progression from mild to severe fatty liver in both sexes. CONCLUSIONS: The presence of severe fatty liver by US correlated significantly with the prevalence and degree of hypertension, abnormal glucose and triglyceride metabolism. Patients with severe fatty liver could be at an increased risk of atherosclerotic cardiovascular disease and should be screened regularly for metabolic disorders. The physician may also evaluate ALT and hepatic fat content by US in patients with metabolic syndrome. Evaluating the severity of fatty liver by US may be useful because it correlates with the status of hyperinsulinemia, the risks of developing cardiovascular disease, and the threshold for oxidative stress.     

非酒精性脂肪性肝病与代谢综合征相关性的临床研究

目的分析非酒精性脂肪性肝病与代谢综合征的关系。方法按住院顺序选择有随访资料病例共185例,将其分为四组（单纯脂肪肝组、单纯肥胖组、脂肪肝＋肥胖组、正常对照组）,在基线水平对四组出现代谢综合征情况进行横向比较。其次,在随访后再次对四组出现代谢综合征情况进行组内、组间比较。结果随访结束时,单纯脂肪肝组代谢综合征发病率明显高于正常对照组（P〈0.05）。结论非酒精性脂肪性肝病促进代谢综合征的发生,且不依赖于肥胖。     

Risk of infections in non-alcoholic fatty liver disease: A nationwide population-based cohort study

Background and Aims

Previous literature suggests an association between non-alcoholic fatty liver disease (NAFLD) and infections. We aimed to determine the rate and risk of severe infections in NAFLD compared to the general population.

Methods

In this population-based cohort study, we used national registers to identify all patients with a hospital-based diagnosis of NAFLD in Sweden 1987–2020 (n = 14 869). The patients were matched with ≤10 comparators from the general population for age, sex, municipality, and calendar year (n = 137 145). Cox regression was used to estimate hazard ratios (HR) for infections in patients with NAFLD compared to comparators. Cumulative incidences were calculated while accounting for competing risks (non-infection death and liver transplantation).

Results

Severe infections leading to death or hospitalization occurred in 1990 (13.4%) patients with NAFLD and 9899 (7.2%) comparators during a median of 4.5 and 6.1 years of follow-up, respectively. The rate of severe infections per 1000 person-years was higher in patients with NAFLD (21.0) than comparators (9.1) independently of components related to the metabolic syndrome (adjusted HR 1.9, 95% CI = 1.8–2.0). Infection-related mortality was also higher in NAFLD compared to comparators (adjusted HR 1.8, 95% CI = 1.6–2.2). The 10-year cumulative incidence of severe infections was 16.6% (95% CI = 15.8–17.4) in NAFLD and 8.0% (95% CI = 7.8–8.2) in comparators.

Conclusion

NAFLD was associated with severe infections and infection-related mortality, independently of components associated with the metabolic syndrome. Increased clinical vigilance of severe infections in NAFLD may diminish the risk of premature death.     

Gallstone disease in non-alcoholic fatty liver: prevalence and associated factors

BACKGROUND: Insulin resistance is a risk factors for non-alcoholic fatty liver disease (NAFLD) and for gallstone disease (GD). Aims of the present study were to assess the prevalence of and factors associated with GD in unselected patients with NAFLD. METHODS: A total of 161 consecutive patients with NAFLD diagnosed through compatible ultrasonography in the absence of known etiologies of liver disease (in all patients) and/or confirmed histologically (in 61 patients), was studied. Gallstone disease was diagnosed through ultrasound scanning or on the basis of previous cholecystectomy. Anthropometric and biochemical variables and concurrent diseases were compared in 32 NAFLD-GD patients and in 129 NAFLD patients without GD (controls) according to gender. RESULTS: The overall prevalence of GD was 19.88%, higher in female patients (P < 0.05), who were older (P < 001). The overall percentage of GD increased with age (P < 0.05). The GD patients had higher uric acid (men), total cholesterol and apolipoprotein B (apo-B) serum concentrations (women; P < 0.05); women also had a higher prevalence of hypertriglyceridemia (P < 0.05). The age-corrected odds ratio of having GD by tertiles increased significantly with increasing uric acid (men) and with increasing total cholesterol, triglycerides and apo-B (women). At univariate continuous analysis GD was associated with insulin 120 min and uric acid in male patients; and with body mass index, insulin 120 min, apo-B, total cholesterol and triglycerides in female patients. On multivariate analysis it was found that among these factors only uric acid in men and apo-B in women were independently associated with GD in NAFLD. CONCLUSIONS: The prevalence of GD in NAFLD is more elevated than reported in the general population. The factors independently associated with GD in NAFLD are different from those reported in the general population and vary according to the gender.     

上海老年人非酒精性脂肪肝的流行情况及相关危险因素调查

目的了解上海地区老年人非酒精性脂肪肝（NAFLD）的发病情况及研究NAFLD相关的性别和与代谢有关的各危险因素。方法记录805名60-92岁的老年人的病史,体格检查及实验室检查结果。比较患NAFLD的老年人与非NAFLD的老年人各项指标的差异用多元logistic回归分析各NAFLD的危险因素。结果上海老年人中的NAFLD患病率为57．67％,男性高于女性,老年男性高TG与NAFLD关系最为密切,而老年女性则以腹围关系最为密切。结论上海老年人中NAFLD的患病率较高,与代谢综合征关系密切,不同性别无显著差异,且与年龄无关。     

体检人群非酒精性脂肪性肝病检出率及其相关因素分析

目的探讨广东地区不同年龄段体检人群非酒精性脂肪性肝病(NAFLD)患病率及相关因素。方法对20047例体检人群进行B超和血生化学检查。结果本组体检人群NAFLD检出率为13.2%,其中单纯性非酒精性脂肪肝检出率为8.7%(1731/20047),非酒精性脂肪性肝炎为4.5%(910/20047),未检出肝硬化和肝癌;随年龄增长,NAFLD检出率逐渐增高,其中60~70岁年龄组人群检出率为25.6%,50~60岁年龄组为23.8%,与小于30岁组、30-岁组、40-岁组和70-岁组比,差异有统计学意义(分别为4.7%、10.8%、17.6%和18.7%,P<0.01);男性人群NAFLD检出率高于女性(18.8%对7.8%,P<0.01),但在60岁以上人群,男性与女性NAFLD检出率无明显差别(22.1%对22.4%,P=0.883);NAFLD患者合并高血压、高血糖、高甘油三酯血症和高胆固醇血症的发生率均高于无NAFLD人群(35.2%对11.7%,14.4%对2.6%,46.8%对10.1%,31.8%对2.5%,P<0.01)。结论 NAFLD的发病与年龄、性别及高血压、高血糖、高甘油三酯血症和高胆固醇血症等因素相关。     

非酒精性脂肪性肝病的研究进展

非酒精性脂肪性肝病经历由非酒精性单纯性脂肪肝发展至非酒精性脂肪性肝炎和肝硬化或原发性肝癌的缓慢过程,并与心血管病的发生关系密切.本文针对非酒精性脂肪性肝病的流行病学、发病机制、诊断和治疗等的研究进展进行综述.     

The association of non-alcoholic fatty liver disease and metabolic syndrome in a Chinese population

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is associated with features of metabolic syndrome. The aim of this study was to investigate the association between NAFLD and metabolic syndrome in a Chinese population.METHODS: Data from subjects were retrospectively collected from 2006 to 2009. The exclusion criteria included significant consumption of alcohol and chronic hepatitis B and C. The patients were assigned to two groups according to ultrasound findings: normal group and fatty liver group. The liver func-tion of patients was determined by assessing serum alanine aminotransferase (ALT). Metabolic syndrome was diagnosed based on the 2005 International Diabetes Federation criteria.RESULTS: A total of 7568 subjects were enrolled and 5736 (75.8%) and 1832 (24.2%) patients were assigned to the nor-mal and fatty liver groups, respectively. The fatty liver group had significant male predominance (69.7% vs 56.0%), higher body mass index (mean, 26.67 vs 23.55 kg/m2) compared with the normal group. There were 441 (7.7%) and 377 (20.6%) cases with metabolic syndrome in the normal and fatty liver groups, respectively, with significant difference (P=0.001), and the subgroup of 385 cases with fatty liver and elevated ALT had higher prevalence (28.8%) of metabolic syndrome. The strongest association of an individual component of meta-bolic syndrome with NAFLD was hyperlipidemia (adjusted OR=2.55, 95% CI: 2.22-2.94).CONCLUSION: The individuals with NAFLD had a higher ra-tio of metabolic syndrome. Hyperlipidemia had the strongest positive association with NAFLD.     

《代谢相关(非酒精性)脂肪性肝病防治指南(2024年版)》解读

随着肥胖和代谢综合征的流行,非酒精性脂肪性肝病(NAFLD)已取代慢性乙型肝炎成为中国第一大慢性肝病。随着对该疾病流行病学和自然史的深入研究、更名、诊断技术的飞速进步以及治疗手段的不断更新,NAFLD的诊疗领域经历了显著发展。最近,中华医学会肝病学分会组织相关专家对《非酒精性脂肪性肝病防治指南(2018更新版)》进行了全面修订,发布了《代谢相关(非酒精性)脂肪性肝病防治指南(2024年版)》。2024年版指南对代谢相关脂肪性肝病的疾病更名与分类、筛查和监测、诊断和评估、治疗和随访等重要临床问题提出了指导性建议。该文旨在通过对该诊疗指南的重要更新点进行解读,以帮助临床工作者更全面深刻地理解指南,并将其应用于指导临床实践。     

Non-invasive fibrosis scoring systems can predict future metabolic complications and overall mortality in non-alcoholic fatty liver disease (NAFLD)

Background and aim: Progression to fibrosis in non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of liver-related events, overall mortality and possibly metabolic comorbidities. Our aim was to determine if non-invasive fibrosis scoring systems can predict the future risk of diabetes mellitus, cardiovascular disease (CVD), chronic kidney disease (CKD), liver-related events and overall mortality.

Methods: Patients with biopsy-proven NAFLD 1978 to 2006 were identified from a computerised register in Malmö, Sweden. Medical records were scrutinised in detail to collect data from inclusion to endpoint (death or end of 2016). Non-invasive fibrosis scoring systems (FIB-4-index, NAFLD fibrosis score (NFS), APRI and BARD score) were calculated and the scores classified into three risk categories (low, intermediate and high risk for advanced fibrosis). Chronic kidney disease was evaluated using the CKD-EPI equation.

Results: One hundred and forty-four patients with biopsy-proven NAFLD were included, with a mean age of 53.2 years and a mean follow-up time of 18.8 years. At inclusion, 18% had advanced fibrosis. NFS was the only score that could predict the future risk of all included outcomes with fairly good accuracy (Area-under-ROC curve). Multivariate-adjusted hazard ratios revealed that both the intermediate and high-risk category of FIB-4-index and NFS could significantly predict metabolic outcomes. All four scoring systems significantly predicted overall mortality in the high-risk category.

Conclusions: Non-invasive fibrosis scoring systems, especially NFS and FIB-4-index, can be used to identify patients at risk of future liver-related events, overall mortality, metabolic comorbidities and CKD.     

奥利司他对肥胖伴非酒精性脂肪性肝病的作用及危险因素的影响

探讨奥利司他(orlistat)在治疗肥胖伴非酒精性脂肪性肝病(NAFLD)中的作用。选择体重指数(BM I)在25和32之间,伴有肝功能异常的NAFLD患者30例,给予奥利司他120mg,日三次口服,治疗24周。治疗结束后,所有患者的体重、BM I、腰围、腰臀比及血压明显下降(P值均<0.001);肝功能中ALT、AST、GGT、Tch、TG及IR与治疗前相比有明显改善(P值均<0.001);肝脏CT密度值及肝/脾CT密度比值均显著增加(P值均<0.001)。奥利司他可有效地减少NAFLD患者肝脏内脂肪沉积,改善肝功能和相关代谢综合征,可作为肥胖伴NAFLD的药物治疗选择。     

活血化痰方对非酒精性脂肪肝大鼠炎性因子的影响

[目的]观察活血化痰方对非酒精性脂肪肝（NAFLD）大鼠炎性因子的影响。[方法]将30只大鼠随机分为正常对照组、模型组和活血化痰方组。检测各组大鼠血清中白细胞介素（IL）-6、IL-10及肿瘤坏死因子-α（TNF-α）的水平。[结果]与正常对照组比较,模型组血清中IL-6、TNF-α水平增高,血清中IL-10含量降低;与模型组相比,活血化痰方组血清中IL-6、TNF-α水平显著降低,血清中IL-10含量显著升高。[结论]活血化痰方可能通过降低血清中IL-6、TNF-α水平,提高血清中IL-10含量,调节体内炎性因子的变化,从而使NAFLD渐愈。     

Non-alcoholic fatty liver disease: an overview

Non-alcoholic fatty liver disease (NAFL) includes a spectrum of clinicopathological conditions with increasing prevalence in the developed world. Although steatosis alone seems to have a benign course, those patients with the diagnosis of non-alcoholic steatohepatitis (NASH) can have a progressive course. Additionally, there is now evolving, indirect evidence that some of the patients with cryptogenic cirrhosis may be the result of 'burned-out' NASH. Although NAFL and NASH are associated with insulin-resistance syndrome, some patients with NAFL may have no obvious risk factors. Despite preliminary data from a number of pilot studies, no established therapies can be offered to patients with NASH. Over the next few years, a number of exciting research projects dealing with the epidemiology as well as the pathogenesis of NAFL are expected to be completed. It is anticipated that, through a better understanding of NAFL, more effective treatment protocols can be developed targeting only those patients with NASH that are at the highest risk for progression to cirrhosis and liver failure.     

Trends in hepatocellular carcinoma due to non-alcoholic fatty liver disease

Introduction: Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and is associated with hepatocellular carcinoma (HCC), the most frequent malignant liver tumor. The increasing prevalence of obesity and diabetes is influencing the epidemiology of HCC with the most dramatic increases in NAFLD-related HCC seen in Western countries. Although cirrhosis is the major risk factor for HCC in NAFLD, there is increasing recognition that NAFLD-HCC occurs in the absence of cirrhosis.

Areas covered: The epidemiology of NAFLD related HCC and its impact on changing the incidence of HCC globally. We overview risk factors for NAFLD-HCC in the presence and absence of cirrhosis and examine trends in liver transplantation (LT) related to NAFLD-HCC.

Expert commentary: The incidence of NAFLD-related cirrhosis will continue to rise globally in parallel with risk factors of obesity and diabetes. Consequently, NAFLD-related HCC will become an increasingly important cause of liver-related morbidity and mortality and a common indication for LT worldwide. Further identification of risk factors for NAFLD-HCC and effective treatments for NAFLD are required to reduce this future burden of disease.