Prevalence of non-alcoholic fatty liver disease and its association with impaired glucose metabolism in Japanese adults.

AIMS: To assess the prevalence of non-alcoholic fatty liver disease (NAFLD) and its association with impaired glucose metabolism in Japanese subjects. METHODS: One thousand, nine hundred and fifty subjects enrolled in a general health examination programme from September 2002 to February 2003 were recruited. NAFLD was diagnosed if a person showed 'fatty liver' on ultrasonography, and his/her alcohol consumption, estimated by questionnaire, was < 40 gram/week. A general linear model was used for the comparison of estimated means of metabolic variables adjusted for age and body mass index (BMI) between subjects with NAFLD and those without fatty liver. Multivariate regression with fasting plasma glucose (FPG) as the dependent variable was performed in 1547 non-diabetic individuals after adjusting for age, gender, BMI and NAFLD. RESULTS: NAFLD was found in 566 of the 1950 health-check examinees (29%). Its prevalence increased with increasing FPG levels: 27% in the subgroup with normal fasting glucose, 43% in impaired fasting glucose and 62% in newly diagnosed diabetes. Adjusted means of FPG, HbA1c, triglyceride, total protein, albumin, AST and ALT were all significantly higher, while adjusted means of HDL cholesterol and AST/ALT ratio were significantly lower in subjects with NAFLD than those without fatty liver. Multivariate regression analysis showed that NAFLD was independently associated with increasing FPG in non-diabetic individuals. CONCLUSIONS: The prevalence of NAFLD was 29% in apparently healthy middle-aged Japanese adults and NAFLD was independently associated with impaired glucose metabolism.     

Recent concepts in non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is present in up to one-third of the general population and in the majority of patients with metabolic risk factors such as obesity and diabetes. Insulin resistance is a key pathogenic factor resulting in hepatic fat accumulation. Recent evidence demonstrates NAFLD in turn exacerbates hepatic insulin resistance and often precedes glucose intolerance. Once hepatic steatosis is established, other factors, including oxidative stress, mitochondrial dysfunction, gut-derived lipopolysaccharide and adipocytokines, may promote hepatocellular damage, inflammation and progressive liver disease. Confirmation of the diagnosis of NAFLD can usually be achieved by imaging studies, however, staging the disease requires a liver biopsy. NAFLD is associated with an increased risk of all-cause death, probably because of complications of insulin resistance such as vascular disease, as well as cirrhosis and hepatocellular carcinoma, which occur in a minority of patients. NAFLD is also now recognized to account for a substantial proportion of patients previously diagnosed with 'cryptogenic cirrhosis'. Diabetes, obesity and the necroinflammatory form of NAFLD known as non-alcoholic steatohepatitis, are risk factors for progressive liver disease. Current treatment relies on weight loss and exercise, although various insulin-sensitizing medications appear promising. Further research is needed to identify which patients will achieve the most benefit from therapy.     

Impact of non-alcoholic fatty liver disease on accelerated metabolic complications

Insulin resistance is the basis of both non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS), the two conditions are often found in the same individual. The mortality of patients with NAFLD is significantly higher than that among the general population and cardiovascular risk may compete with liver-related risk in dictating the final outcome. Recent prospective studies have reported that NAFLD is associated with an increased incidence of MetS and type 2 diabetes mellitus, independent of obesity and other components of MetS. Thus, NAFLD may not only be a liver disease but also an early mediator of type 2 diabetes mellitus and MetS. The biological mechanisms by which NAFLD contributes to a higher risk of developing metabolic disorders are not fully understood. However, the fatty liver could contribute in the same way as visceral adipose tissue to insulin resistance, systemic inflammation and oxidative stress, while the decreased serum adiponectin concentrations might also be part of the mechanism. In contemporary clinical practice, it has become mandatory to evaluate the metabolic risk factors in NAFLD patients and to consider careful surveillance and aggressive treatment, not only of the resultant liver disease, but also of the possible underlying metabolic and vascular complications. Future studies might address the question whether earlier adjustment to a more efficient lifestyle or a pharmacological treatment that mobilizes fat out of the liver could reduce these risks.     

Clinicopathological features of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease worldwide and its incidence is increasing concomitantly with the increase in the prevalence of metabolic syndrome. Fatty liver encompasses a broad pathological spectrum of disease, from relatively benign accumulation of fat (simple steatosis) to progressive non-alcoholic steatohepatitis (NASH), which is associated with necroinflammation and fibrosis. Approximately 20-30% of the Japanese population is estimated to have NAFLD, 10% of which is suggested to have NASH. The most worrisome feature of NASH is the potential progression to cirrhosis, hepatocellular carcinoma (HCC), and finally, mortality. Several factors, such as insulin resistance, adipokines, endotoxins and oxidative stress, are involved in the pathogenesis of NASH. However, the precise etiological mechanism of NAFLD/NASH has yet to be elucidated. This article reviews the clinical background, pathogenesis, new diagnostic approaches and future directions regarding NAFLD/NASH.     

Genetic variation in PNPLA3 but not APOC3 influences liver fat in non-alcoholic fatty liver disease

Background and Aim: A recent study in Indian subjects suggested common variants in apolipoprotein C3 (APOC3) (T‐455C at rs2854116 and C‐482T at rs2854117) to contribute to non‐alcoholic fatty liver disease (NAFLD), plasma apoC3 and triglyceride concentrations. Our aim was to determine the contribution of genetic variation in APOC3 on liver fat content and plasma triglyceride and apoC3 concentrations in a larger European cohort. Methods: A total of 417 Finnish individuals were genotyped for rs2854116 and rs2854117 in APOC3 and the known rs738409 in patatin‐like phospholipase domain‐containing protein 3 (PNPLA3) influencing liver fat. Plasma apoC3 concentration was measured enzymatically, and liver fat by proton magnetic resonance spectroscopy. Results: APOC3 wild‐type homozygotes and variant allele (T‐455C or C‐482T or both) carriers did not differ with regard to liver fat, apoC3 concentrations, triglyceride‐, high density lipoprotein‐, fasting plasma glucose, insulin‐, alanine aminotransferase‐ and aspartate aminotransferase‐concentrations, nor was there a difference in prevalence of NAFLD. In contrast, carriers of the PNPLA3 GG genotype at rs738409 had a 2.7‐fold (median 11.3%) higher liver fat than those with the CC (median 4.2%) genotype. The PNPLA3 rs738409 was also an independent predictor of liver fat, together with age, gender, and body mass index. Conclusion: Genetic variants in PNPLA3 but not APOC3 contribute to the variance in liver fat content due to NAFLD.     

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the Western world. It is closely associated with metabolic syndrome. The alarming epidemics of diabetes and obesity have fueled an increasing prevalence of NAFLD, particularly among these high-risk groups. Histologically, NAFLD encompasses a disease spectrum ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), which is characterized by hepatocyte injury, inflammation, and variable degrees of fibrosis on liver biopsy. Non-alcoholic steatohepatitis can progress to cirrhosis in a fraction of patients. There is currently little understanding of risk factors for disease progression and the disease pathogenesis has not been fully defined. Liver biopsy remains the gold standard for diagnosis. Weight loss, dietary modification, and the treatment of underlying metabolic syndrome remain the mainstays of therapy once the diagnosis is established. There are no well-established pharmacological agents for treatment of NASH, although this is a subject of ongoing research.     

Non-alcoholic fatty liver disease, the metabolic syndrome and the risk of cardiovascular disease: the plot thickens.

Non-alcoholic fatty liver disease (NAFLD) affects a substantial proportion of the general population and is frequently associated with many features of the metabolic syndrome (MetS). Currently, the importance of NAFLD and its relationship with the MetS is being increasingly recognized, and this has stimulated an interest in the possible role of NAFLD in the development of atherosclerosis. Recent studies have reported the association of NAFLD with multiple classical and non-classical risk factors for cardiovascular disease (CVD). Moreover, there is a strong association between the severity of liver histopathology in NAFLD patients and greater carotid artery intima-media thickness and plaque, and lower endothelial flow-mediated vasodilation (as markers of subclinical atherosclerosis) independent of obesity and other MetS components. Finally, it has recently been demonstrated that NAFLD is associated with an increased risk of all-cause death and predicts future CVD events independently of other prognostic factors, including MetS components. Overall, therefore, the evidence from these recent studies strongly emphasizes the importance of assessing the global CVD risk in patients with NAFLD. Moreover, these novel findings suggest a more complex picture and raise the possibility that NAFLD, as a component of the MetS, might not only be a marker but also an early mediator of CVD.     

Prevalence and clinical associations of posttransplant fatty liver disease.

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease (NAFLD) could recur after liver transplant in patients with preexisting NAFLD, and has recently been reported to occur after transplant in patients transplanted without preexisting NAFLD. The literature on posttransplant NAFLD is limited. We aimed to study the prevalence of posttransplant NAFLD in patients transplanted for non-NAFLD-related liver diseases. METHODS: Thirty liver transplant recipients: 18 with chronic hepatitis B (CHB), seven with chronic hepatitis C (CHC), five others, were recruited. Liver biopsies were performed in all CHB and CHC patients annually as per protocol, or when clinically indicated. All biopsies were reviewed by one hepato-histopathologist blindly to assess and stage for steatosis and steatohepatitis. RESULTS: After a mean follow-up of 44+/-4 months, 12 (40%) and four (13%) developed posttransplant steatosis and steatohepatitis, respectively. None developed steatosis-related fibrosis or cirrhosis. Posttransplant steatohepatitis was associated with higher pretransplant body mass index (BMI) (32.3+/-3.9 vs 23.1+/-0.8, P=0.02) and higher BMI at last biopsy (32.5+/-4.3 vs 22.9+/-0.7, P=0.01). CONCLUSION: Posttransplant steatosis is common after liver transplant even in patients transplanted for non-NAFLD-related liver diseases. However, it is mostly benign during our follow-up, with only 13% developing steatohepatitis and none with fibrosis or cirrhosis.     

Current therapeutic strategies in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease ranging from simple steatosis through steatohepatitis (NASH) to increasing fibrosis and eventual cirrhosis. NAFLD is the hepatic manifestation of the metabolic syndrome and has now become the most common cause of liver disease in Western countries, with the more advanced stages of disease being associated with an increased risk of liver-related morbidity and mortality. The optimal management of patients with NAFLD remains a clinical challenge. The aim of this study is to describe established and emerging strategies for the treatment of NAFLD. Relevant research and review articles were identified by searching PubMed. Selected articles referenced in these publications were also examined. Good quality randomized controlled studies have demonstrated the need for multifaceted lifestyle interventions in patients with NAFLD including the need for diet, exercise and behavioural counselling. Despite several trials of pharmacological agents, no highly effective treatment yet exists, with surgery representing the mainstay for advanced disease. A multidisciplinary approach, with a major focus on lifestyle change, represents best treatment pending the development of new therapeutic options.     

Relationship between non-alcoholic fatty liver disease and pulmonary function

Background: It has been observed that non‐alcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiovascular disease and insulin resistance. Pulmonary function is also known to be related with cardiovascular disease and metabolic syndrome. Aims: The objective of this study was to investigate the association between NAFLD and pulmonary function. Methods: We performed a cross‐sectional study to examine the association of NAFLD based on abdominal sonographic findings and pulmonary function in 2119 Korean men between the ages of 30 and 75. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were compared according to the presence of NAFLD. Univariate and multivariate logistic regression analyses were conducted to evaluate the relationship of NAFLD with FVC and FEV₁ as pulmonary function tests. Results: The subjects with NAFLD had lower FVC and FEV₁ than their non‐steatotic counterparts, and FVC and FEV₁ gradually decreased according to the grade of hepatic steatosis. After adjusting for age, body mass index, smoking status, blood pressure, fasting plasma glucose, total cholesterol, hypertension, diabetes, triglyceride and high‐density lipoprotein cholesterol, the FVC and FEV₁ were found to be inversely associated with the presence of NAFLD. Conclusion: NAFLD was independently associated with reduced pulmonary function, and the severity of NAFLD was inversely correlated with pulmonary function.     

Histopathological characteristics of non-alcoholic fatty liver disease in children: Comparison with adult cases

Aim: Non-alcoholic steatohepatitis (NASH) has been classified pathologically into type 1 (characterized by ballooning and perisinusoidal fibrosis) and type 2 (characterized by portal inflammation and portal fibrosis). Reportedly, type 2 NASH has been the most commonly observed histopathological feature in pediatric non-alcoholic fatty liver disease (NAFLD). While only a few studies have documented the histopathology of pediatric NAFLD so far, appropriate histopathological classification or characteristics of pediatric NAFLD, and the disease incidence correlation with race or ethnicity are still controversial. Methods: In this study, we compared the clinical and histopathological characteristics of NAFLD in 34 pediatric and 23 adult cases. Results: We found that pediatric steatosis was more severe than adult steatosis. Perisinusoidal fibrosis was significantly milder in pediatric cases than in adult cases. Lobular inflammation and ballooning was found to be milder in pediatric cases than in adult cases. On the other hand, portal inflammation was more severe in pediatric cases than in adult cases. The so-called borderline zone 1 NASH, similar to type 2 NASH, was observed in 21% of pediatric subjects; this rate was more than twice that in adult subjects. Fifty percent of pediatric cases showed overlapping features of types 1 and 2 NASH. Intralobular and portal changes showed positive and significant correlations with each other. Serum aminotransferase levels reflected the histopathological severity of NAFLD. Conclusion: We confirmed that pediatric NAFLD exhibits histopathological features that are different from adult NAFLD. The classification consisting of "type 1 NASH" and "type 2 NASH" may be impractical.     

Metabolic syndrome and non‐alcoholic fatty liver disease after liver or kidney transplantation

Transplantation is a definitive treatment option for patients with end‐stage liver disease, and for some patients with acute liver failure, hepatocellular carcinoma or end‐stage renal disease. Long‐term post‐transplantation complications have become an important medical issue, and cardiovascular diseases (CVD) are now the leading cause of mortality in liver or kidney transplant recipients. The increased prevalence of metabolic syndrome (MS) likely plays a role in the high incidence of post‐transplantation CVD. MS and its hepatic manifestation, non‐alcoholic fatty liver disease (NAFLD), are prevalent among the general population and in pre‐ and post‐transplantation settings. MS components are associated with recurrent or de novo NAFLD in transplant recipients, potentially influencing post‐transplantation survival. Moreover, recent data reveal an important association between NAFLD and risk of incident of chronic kidney disease (CKD). Therefore, NAFLD identification could represent an additional clinical feature for improving the stratification of liver and kidney transplant recipients with regards to risks of CVD, CKD and renal allograft dysfunction. All MS components are potentially modifiable; therefore, it is crucial that hepatologists, nephrologists and primary care physicians become more engaged in managing post‐transplantation metabolic complications. The present review discusses the recent clinical evidence regarding the importance of MS and its components after liver and kidney transplantation, as well as the link between MS and NAFLD after liver and kidney transplantation.     

Transitional features of histologic type of non-alcoholic fatty liver disease in Korean young men

Background and Aim: The prevalence of non‐alcoholic fatty liver disease (NAFLD) is increasing in Korea as the dietary pattern and lifestyle become more Westernized and the obese population increases. The spectrum of NAFLD ranges from asymptomatic steatosis to non‐alcoholic steatohepatitis (NASH) and cirrhosis. Schwimmer et al. divided NASH into three types according to the histological characteristics, such as adult type, pediatric type and overlap type. We investigated clinical and histologic features of NAFLD patients in Korean young men. Methods: A total of 64 male patients under age 30 years, diagnosed as NAFLD by a liver biopsy, were reviewed retrospectively. NASH was diagnosed by NAFLD activity score (NAS), and NASH patients were classified with Schwimmer's histological classification. Results: Pathological features of liver biopsy revealed NASH in most cases (59 cases, 92.2%) including 29 cases (45.3%) of borderline NASH and 30 cases (46.9%) of definite NASH. The definite NASH group showed significantly high aspartate aminotransferase/alanine aminotransferase levels compared to the borderline NASH group. There were four cases (6.8%) of pediatric type, 17 cases (28.8%) of adult type, and 38 cases (64.4%) of overlap type in the NASH group. NAS was 3.75 ± 0.05 in the pediatric type, 4.29 ± 1.16 in the adult type and 4.87 ± 1.21 in the overlap type, and the overlap type showed a higher NAS than the pediatric type. The fibrosis stage was significantly higher in the overlap type than the other types. Conclusion: Most Korean young men with NAFLD turned out to have borderline or definite NASH. More than half of the NASH cases showed overlap type in Korean young men.     

Difference in malignancies of chronic liver disease due to non-alcoholic fatty liver disease or hepatitis C in Japanese elderly patients

Aim: Malignancies that include hepatocellular carcinoma often occurred in patients with chronic liver disease. The aim of this retrospective match control study was to assess the cumulative development incidence and predictive factors for total malignancies in elderly Japanese patients with non‐alcoholic hepatic diseases (NAFLD) or hepatitis C virus (HCV). Methods: A total of 1600 NAFLD patients with age of ≥60 years were enrolled, and 1600 HCV patients with age of ≥60 years were selected as control by matching 1:1 with NAFLD group for age, sex, and follow‐up period. The primary goal is the first development of malignancies. Evaluation was performed by the use of the Wilcoxon rank sum test, the Kaplan–Meier method, and Cox proportional hazard model. The mean observation period is 8.2 years in both NAFLD and HCV group, respectively. Results: The number of patients with the development of malignancies was 167 in the NAFLD group and 395 in the HCV group. The 10th development rate of malignancies was 13.9% in the NAFLD group and 28.2% in the HCV group (risk ratio 2.27; P < 0.001). The incident rates of hepatocellular carcinoma in all the malignancies were 6.0% (10/167) in the NAFLD group and 67.6% (267/395) in the HCV group (P < 0.001). The malignancies in the NAFLD group were observed in the following order: gastric cancer 34 cases (20.4%) > colon cancer 31 cases (18.6%) > prostate cancer 21 cases (12.6%). Conclusions: The incident rates of hepatocellular carcinoma in all the malignancies were approximately 6% in the NAFLD group and two‐thirds in the HCV group.     

非酒精性脂肪性肝病在心血管疾病发生发展中的作用

随着经济水平的提高、饮食结构和生活方式的改变,非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD)的发病率不断上升,逐渐成为全球慢性肝病的主要病因.心血管疾病(cardiovascular disease,CVD)作为NAFLD患者的主要死亡原因,越来越多的研究发现两者之间存在相关性;NAFLD患者CVD发生发展的风险更大,其机制可能与血管和内皮细胞功能障碍、胆汁酸代谢、氧化应激、全身炎症反应和肾素-血管紧张素系统的激活等相关.其中,代谢综合征在两者联系中发挥了重要的作用.因此,早期识别NAFLD患者心血管疾病相关危险因素,进而减少心血管相关并发症,对于改善该类患者的预后至关重要.     

Prevalence and associated factors of non‐alcoholic fatty liver disease in patients with type‐2 diabetes mellitus

Background/Aims: Diabetic patients have an increased prevalence and severity of non‐alcoholic fatty liver disease (NAFLD). We aimed to investigate the prevalence and the factors associated with the presence of ultrasonographic NAFLD in type‐2 diabetic individuals. Methods: In a cross‐sectional design study, 180 type‐2 diabetic patients were submitted to a complete clinical and laboratory evaluation and abdominal ultrasonography for NAFLD detection and grading. Statistical analysis included bivariate tests, analysis of variance (anova , for increasing severity of steatosis) and multivariate logistic regression. Results: The prevalence of ultrasonographic NAFLD was 69.4% [95% confidence interval (CI): 58.3–82.7%]. Patients with NAFLD were more obese, had a higher waist circumference and serum triglyceride and alanine aminotransferase (ALT) levels than those without steatosis. Neither diabetic degenerative complication, nor glycaemic control was associated with liver steatosis. On multivariate analysis, a high serum triglycerides level [>2.82 mmol/L, odds ratio (OR): 3.7–4.1, 95% CI: 1.2–13.3] and a high‐normal ALT level (≥40 U/L, OR: 2.5–2.7, 95% CI: 1.2–5.9) were independently associated with hepatic steatosis, together with either the presence of obesity (OR: 7.1, 95% CI: 3.0–17.0) or of increased waist circumference (OR: 4.8, 95% CI: 1.9–12.2). Conclusions: Type‐2 diabetic patients have a high prevalence of ultrasonographic NAFLD and its presence is associated with obesity, mainly abdominal, hypertriglyceridaemia and high‐normal ALT levels. Non‐alcoholic fatty liver disease in diabetic patients may develop and progress independent of the diabetes progression itself.     

Usefulness of Technetium-99 m-2-methoxy-isobutyl-isonitrile liver scintigraphy for evaluating disease activity of non-alcoholic fatty liver disease

Aim: Non‐alcoholic steatohepatitis (NASH) is a progressive form of non‐alcoholic fatty liver disease (NAFLD). Therefore, it is important to evaluate disease activity and distinguish NASH from simple steatosis in NAFLD. Technetium‐99 m‐2‐methoxy‐isobutyl‐isonitrile (^99mTc‐MIBI) is a lipophilic cation designed for myocardial perfusion scintigraphy in the diagnosis of ischemic heart diseases, and its retention reflects mitochondrial function. It was reported that hepatic mitochondrial abnormalities would be an important predictive factor for NASH disease progression. The aim of this study was to examine the clinical usefulness of ^99mTc‐MIBI liver scintigraphy for evaluating disease activity of NAFLD and distinguishing NASH from simple steatosis in patients with NAFLD. Methods: Twenty‐six patients with biopsy‐proven NAFLD were enrolled. Clinicolaboratory tests and ^99mTc‐MIBI liver scintigraphy were performed. To evaluate hepatic uptake, regions of interest were set at the liver and heart, and the uptake ratio of the liver to heart (liver/heart ratio) was calculated. Results: All patients with NAFLD were classified into three groups according to the NAFLD activity score: non‐NASH (simple steatosis) (n = 4), borderline NASH (n = 11), and NASH (n = 11). Liver/heart ratios were significantly lower in NASH than in simple steatosis (P < 0.05). Moreover, liver/heart ratios were significantly correlated with NAFLD activity scores among the patients (r = ?0.413, P < 0.05). Conclusions: The present study indicates that ^99mTc‐MIBI liver scintigraphy would be a useful non‐invasive functional imaging method with which to evaluate disease activity of NAFLD and distinguish NASH from simple steatosis.     

Non‐alcoholic fatty liver disease (NAFLD) prevalence and its metabolic associations in patients with type 1 diabetes and type 2 diabetes

We investigated non‐alcoholic fatty liver disease (NAFLD) prevalence and its metabolic associations in patients with type 1 diabetes (T1D), and in insulin‐naïve and insulin‐treated patients with type 2 diabetes (T2D). Baseline data from patients who had liver fat content (LFC) evaluated by magnetic resonance imaging in four phase 3 studies of basal insulin peglispro (BIL) were analysed. Associations of NAFLD with clinical characteristics, glycaemic control and diabetes therapy were evaluated. The prevalence of NAFLD (defined as LFC ≥ 6%) was low in T1D (8.8%) but high in T2D, with greater prevalence in insulin‐naïve (75.6%) vs insulin‐treated (61.7%) T2D patients. LFC (mean ± SD) was higher in T2D patients (insulin‐naïve, 13.0% ± 8.4%; insulin‐treated, 10.2% ± 7.8%) than in T1D patients (3.2% ± 3.2%). In T2D, NAFLD was associated with several markers of insulin resistance. In all three populations, there was an absence of association of HbA1c with LFC, but insulin doses were higher in patients with NAFLD.