Is alcohol a risk factor for liver cirrhosis in HBsAg and anti-HCV negative subjects? Collaborative Groups for the Study of Liver Diseases in Italy

Alcohol Consumption and Risk of Liver Cirrhosis: A Systematic Review and Meta-Analysis

OBJECTIVES

To systematically summarize the risk relationship between different levels of alcohol consumption and incidence of liver cirrhosis.

METHODS

MEDLINE and Embase were searched up to March 6, 2019, to identify case-control and cohort studies with sex-specific results and more than 2 categories of drinking in relation to the incidence of liver cirrhosis. Study characteristics were extracted and random-effects meta-analyses and meta-regressions were conducted.

RESULTS

A total of 7 cohort studies and 2 case-control studies met the inclusion criteria, providing data from 2,629,272 participants with 5,505 cases of liver cirrhosis. There was no increased risk for occasional drinkers. Consumption of one drink per day in comparison to long-term abstainers showed an increased risk for liver cirrhosis in women, but not in men. The risk for women was consistently higher compared to men. Drinking ≥5 drinks per day was associated with a substantially increased risk in both women (relative risk [RR] = 12.44, 95% confidence interval [CI]: 6.65-23.27 for 5-6 drinks, and RR = 24.58, 95% CI: 14.77-40.90 for ≥7 drinks) and men (RR = 3.80, 95% CI: 0.85-17.02, and RR = 6.93, 95% CI: 1.07-44.99, respectively). Heterogeneity across studies indicated an additional impact of other risk factors.

DISCUSSION

Alcohol is a major risk factor for liver cirrhosis with risk increasing exponentially. Women may be at higher risk compared to men even with little alcohol consumption. More high-quality research is necessary to elucidate the role of other risk factors, such as genetic vulnerability, body weight, metabolic risk factors, and drinking patterns over the life course. High alcohol consumption should be avoided, and people drinking at high levels should receive interventions to reduce their intake.

Alcohol and hepatocellular carcinoma

BACKGROUND

Alcohol is classified as a Group 1 carcinogen by the International Agency for Research on Cancer because it induces hepatocellular carcinoma (among other cancers) in humans. An excessive alcohol intake may result in fatty liver, acute/chronic hepatitis, and cirrhosis and eventually lead to hepatocellular carcinoma. It has been reported that alcohol abuse increases the relative risk of hepatocellular carcinoma by 3- to 10-fold.

AIM AND METHODS

To clarify the known mechanisms of alcohol-related carcinogenesis, we searched Pubmed using the terms alcohol and immune mechanism, alcohol and cancer, and immune mechanism and cancer and summarized the articles as a qualitative review.

RESULTS

From a clinical perspective, it is well known that alcohol interacts with other factors, such as smoking, viral hepatitis, and diabetes, leading to an increased risk of hepatocellular carcinoma. There are several possible mechanisms through which alcohol may induce liver carcinogenicity, including the mutagenic effects of acetaldehyde and the production of ROS due to the excessive hepatic deposition of iron. Furthermore, it has been reported that alcohol accelerates hepatitis C virus-induced liver tumorigenesis through TLR4 signaling. Despite intense investigations to elucidate the mechanisms, they remain poorly understood.

CONCLUSION

This review summarizes the recent findings of clinical and pathological studies that have investigated the carcinogenic effects of alcohol in the liver.

Alcohol-induced liver injury is modulated by Nlrp3 and Nlrc4 inflammasomes in mice

Alcoholic liver disease (ALD) is characterized by increased hepatic lipid accumulation (steatosis) and inflammation with increased expression of proinflammatory cytokines. Two of these cytokines, interleukin-1β (IL-1β) and IL-18, require activation of caspase-1 via members of the NOD-like receptor (NLR) family. These NLRs form an inflammasome that is activated by pathogens and signals released through local tissue injury or death. NLR family pyrin domain containing 3 (Nlrp3) and NLR family CARD domain containing protein 4 (Nlrc4) have been studied minimally for their role in the development of ALD. Using mice with gene targeted deletions for Nlrp3 (Nlrp3^−/−) and Nlrc4 (Nlrc4^−/−), we analyzed the response to chronic alcohol consumption. We found that Nlrp3^−/− mice have more severe liver injury with higher plasma alanine aminotransferase (ALT) levels, increased activation of IL-18, and reduced activation of IL-1B. In contrast, the Nlrc4^−/− mice had similar alcohol-induced liver injury compared to C57BL/6J (B6) mice but had greatly reduced activation of IL-1β. This suggests that Nlrp3 and Nlrc4 inflammasomes activate IL-1β and IL-18 via caspase-1 in a differential manner. We conclude that the Nlrp3 inflammasome is protective during alcohol-induced liver injury.

Review article: alcoholic liver disease--pathophysiological aspects and risk factors

BACKGROUND

Alcoholic liver disease has a known aetiology but a complex and incompletely known pathogenesis. It is an extremely common disease with significant morbidity and mortality, but the reason why only a relatively small proportion of heavy drinkers progress to advanced disease remains elusive.

AIM

To recognize the factors responsible for the development and progression of alcoholic liver disease, in the light of current knowledge on this matter.

METHODS

We performed a structured literature review identifying studies focusing on the complex pathogenetic pathway and risk factors of alcoholic liver disease. Results In addition to the cumulative amount of alcohol intake and alcohol consumption patterns, factors such as gender and ethnicity, genetic background, nutritional factors, energy metabolism abnormalities, oxidative stress, immunological mechanisms and hepatic co-morbid conditions play a key role in the genesis and progression of alcoholic liver injury.

CONCLUSIONS

Understanding the pathogenesis and risk factors of alcoholic liver disease should provide insight into the development of therapeutic strategies.

Southern Europe as an example of interaction between various environmental factors: a systematic review of the epidemiologic evidence

Hepatitis B virus (HBV), hepatitis C virus (HCV) and alcohol consumption are major causes of hepatocellular carcinoma (HCC) worldwide. We performed a systematic review of epidemiologic studies carried out on HCC aetiology in Southern Europe, an area with an intermediate-high prevalence of these agents as well as of putative risk factors such as tobacco smoking, diabetes and obesity. To retrieve the articles, we performed a Medline search for titles and abstracts of articles. After the Medline search, we reviewed the papers and reference lists to identify additional articles. A synergism between HCV infection and HBV infection, overt (hepatitis B virus antigen (HbsAg) positivity) or occult (HBsAg negativity with presence of HBV DNA in liver or serum), is suggested by the results of some studies. The pattern of the risk for HCC due to alcohol intake shows a continuous dose-effect curve without a definite threshold, although most studies found that HCC risk increased only for alcohol consumption above 40-60 g of ethanol per day. Some evidence supports a positive interaction of alcohol intake probably with HCV infection and possibly with HBV infection. A few studies found that coffee has a protective effect on HCC risk due to various risk factors. Some data also support a role of tobacco smoking, diabetes and obesity as single agents or preferably co-factors in causing HCC. In countries with a relatively high alcohol consumption and intermediate levels of HCV and HBV infections (1-3% of population infected by each virus), such as Mediterranean countries, the three main risk factors together account for about 85% of the total HCC cases, leaving little space to other known risk factors, such as haemochromatosis, and to new, still unrecognised, factors as independent causes of HCC.

Nutrient intakes, nutritional patterns and the risk of liver cirrhosis: an explorative case-control study

Several experimental studies have suggested that specific nutrients might play a role on the risk of liver damage. Nevertheless, few epidemiological studies have evaluated the role of diet on the risk of symptomatic liver cirrhosis, giving contradictory results. To evaluate the role of the intake of nutritional factors and dietary patterns on the risk of symptomatic liver cirrhosis and to examine their combined action with alcohol consumption we used data from the Italian Study on Liver Cirrhosis Determinants project. From 1994 to 1998 all the consecutive cirrhotic inpatients admitted to 19 Italian collaborative hospitals for signs of liver decompensation in whom the diagnosis of liver cirrhosis was made for the first time (259 cases) and one or two gender, age and area of residence matched individuals (416 controls) were recruited. Data on lifetime alcohol intake, usual consumption of 191 food items and on markers of hepatitis B and C viral infection were collected. The analysis of principal components identified a nutritional pattern positively correlated with vegetable and fruit intakes and negatively with animal and no-fruit sugar products. With respect to abstainers, relative risks in consumers of use < or = 25 and > or = 51 g/day of alcohol increased from 0.4 [95% confidence interval 0.0, 5.9] to 9.3 [1.3, 69.0] and from 2.1 [1.1, 4.2] to 18.1 [2.8, 118.3] for the lowest and the highest value of this nutritional pattern, respectively. Diet might therefore modulate the damaging effect of alcohol on the liver.

Alcohol and cirrhosis: dose--response or threshold effect?

BACKGROUND/AIMS

General population studies have shown a strong association between alcohol intake and death from alcoholic cirrhosis, but whether this is a dose-response or a threshold effect remains unknown, and the relation among alcohol misusers has not been studied.

METHODS

A cohort of 6152 alcohol misusing men and women aged 15-83 were interviewed about drinking pattern and social issues and followed for 84,257 person-years. Outcome was alcoholic cirrhosis mortality. Data was analyzed by means of Cox-regression models.

RESULTS

In this large prospective cohort study of alcohol misusers there was a 27 fold increased mortality from alcoholic cirrhosis in men and a 35 fold increased mortality from alcoholic cirrhosis in women compared to the Danish population. Number of drinks per day was not significantly associated with death from alcoholic cirrhosis, since there was no additional risk of death from alcoholic cirrhosis when exceeding an average daily number of five drinks (>60 g/alcohol) in neither men nor women.

CONCLUSIONS

The results indicate that alcohol has a threshold effect rather than a dose-response effect on mortality from alcoholic cirrhosis in alcohol misusers.

Etiology of hepatocellular carcinoma influences clinical and pathologic features but not patient survival

OBJECTIVE

We investigated the relation between hepatocellular carcinoma (HCC) etiology and biological and clinical parameters indicative of severity of liver disease and/or tumor characteristics and patient survival.

METHODS

We prospectively recruited 384 patients (82.3% male) with first diagnosis of HCC from 1995 to 1998 in Brescia, Italy. Etiology was assessed by interviewing patients regarding their history of alcohol intake and by testing sera for hepatitis B surface antigen and anti-hepatitis C virus (HCV) antibodies and HCV RNA.

RESULTS

Heavy alcohol intake (>60 g of ethanol per day for at least 1 decade) was found in 33.1% of cases, hepatitis B virus (HBV) infection in 9.4%, HCV in 19.8%, hemochromatosis in 1.3%, alcohol and HBV in 12.0%, alcohol and HCV in 16.1%, HBV and HCV in 3.1%, and no factor in 5.2%. Patients with HBV infection with or without heavy alcohol intake were significantly younger than the others (61.7 vs 64.7 yr, p < 0.001). The proportion of males was significantly higher in patients with heavy alcohol intake alone than in the other patient groups (93.7% vs 77.3%, p < 0.001). Among patients with HCV infection with or without heavy alcohol intake, fewer patients had maximum tumor diameter > 5 cm than the others (12% vs 29.1%, p < 0.001). Eighty patients (20.8%) were alive at the end of follow-up (median survival, 17.7 months), and no differences were observed in survival rates by HCC risk factor.

CONCLUSIONS

Although some differences were observed in severity of liver disease or tumor characteristics according to etiology, patient survival was not influenced by HCC etiology.

Moderate alcohol intake increases fibrosis progression in untreated patients with hepatitis C virus infection

Although excessive alcohol consumption in combination with hepatitis C virus (HCV) infection is known to increase the risk of liver cirrhosis, the effect of moderate alcohol intake remains to be elucidated. The aim of this study was to evaluate the effect of moderate alcohol consumption on fibrosis progression in HCV infection. A group of 78 patients with HCV infection and moderate alcohol consumption were analysed retrospectively. All patients had undergone two liver biopsies, with a median time between biopsies of 6.3 years, and had not received any antiviral therapy. Their lifetime drinking history was recorded. All patients except one had daily alcohol consumption below 40 g of ethanol (median 4.8 g/day, interquartile range 1.1-11.6 g/day) during the period between the biopsies. The patients whose liver fibrosis had deteriorated had a higher total alcohol consumption and higher drinking frequency between the biopsies. The degree of fibrosis progression was greater in patients with a total alcohol intake and drinking frequency above the median level for the group. A multiple logistic regression analysis showed that drinking frequency and time between biopsies were independently associated with fibrosis progression. Hence, even moderate alcohol intake seems to increase fibrosis progression in HCV-infected patients. From that point of view, total abstention ought to be recommended. If this is not achieved, occasional use of alcohol is probably less harmful than daily drinking for patients with low or moderate alcohol consumption.

Hepatitis C and alcohol

A close relationship and possible interaction has been noted between alcohol intake and hepatitis C virus infection, since the discovery of HCV markers. It is not understood whether these are additive or synergistic effects in causing liver injury. Interactions between alcohol and HCV may be studied at several levels, including epidemiology, virology (including viral load), histology (effect on the severity of liver lesions), carcinogenesis (the role of alcohol in the occurrence of hepatocellular carcinoma), and the effect on the extrahepatic manifestations or severity of HCV infection. At the epidemiological level, a high prevalence of HCV infection was noted in patients with alcoholic liver diseases (14-37%), also characterized by a high rate of viral replication as detected by PCR, which was present in over 90% of patients tested. Moreover, the prevalence of anti-HCV antibodies increased proportionally with the severity of liver lesions. Virological analysis based on the determination of HCV RNA levels in the serum showed variations of HCV RNA levels with diet, and a clear relationship between self reported alcohol consumption and the levels of serum HCV RNA (r = .26, p = .001). At the histologic level the role of alcohol may be evaluated either through the development of fibrosis or by determination of the incidence of cirrhosis. A study on the effect of alcohol intake below or over 40 g per day on the histologic progression of liver lesions has confirmed a more rapid increase in fibrosis and a doubling in the incidence of cirrhosis in patients admitting to alcohol consumption >40 g per day. The role of alcohol in the occurrence of hepatocellular carcinoma in patients with cirrhosis due to HCV infection has been extensively studied with controversial results. A recent case control study performed in Italy showed that the relative risk of HCC in patients with HCV infection and heavy alcohol consumption doubled. Finally, alcohol consumption potentially worsens the evolution of dermatological diseases associated with HCV infection such as porphyria cutanea tarda. All of the above are strong arguments which should be used to advise HCV patients against alcohol consumption, regardless of the degree of liver injury. However, the deleterious effect of the occasional intake of small amounts of alcohol has not been demonstrated and therefore an occasional drink may be allowed in some cases.

The inheritance of alcoholic liver disease

Available evidence supports the concept that alcoholic liver disease (ALD) is a multifactorial disease with a heritable component. A number of polymorphic genes with small and additive effects will thus encode susceptibilty to this 'polygenic' disease. Molecular genetic studies of ALD are in their infancy, and methods available for the genetic dissection of complex traits are discussed. Some candidate genes have been identified, and studies have been undertaken to test for association between specific alleles and ALD susceptibility. There is evidence to support a role for alleles of two genes encoding enzymes involved in the oxidative metabolism of alcohol (acetaldehyde dehydrogenase2*2 and cytochrome P4502E1 c2 allele) in susceptibility to ALD. More recently, attention has focused on cytokines, and there are now data showing association of specific alleles of both tumour necrosis factor alpha and interleukin-10 with predisposition to ALD. These candidate genes need to be subjected to rigorous evaluation in different populations. Such research should help to define more precisely the molecular mechanisms underlying the development of ALD in a sub-population (< 20%) of alcoholics, thereby improving the hepatologist's ability to develop rational treatments.