The Effect of Caffeine and Alcohol Consumption on Liver Fibrosis

A Study of 1045 Asian Hepatitis B Patients Using Transient Elastography

Arlinking Ong; Vincent Wai-SunWong; Grace Lai-Hung Wong; Henry Lik-Yuen Chan

Disclosures

Liver International. 2011;31(7):1047-1053. 

In This Article

Discussion

In this large territory-wide observational study with prospective recruitment, we assessed the relationship between caffeine and alcohol consumption and the risk of advanced liver fibrosis in chronic hepatitis B patients with different disease severity. Caffeine intake was not associated with advanced fibrosis. Patients who drank coffee regularly were more likely to consume alcohol. On the other hand, few chronic hepatitis B patients in Hong Kong had excessive alcohol consumption. Mild to moderate alcohol consumption did not increase the risk of advanced fibrosis.

Coffee is a rich source of a number of phenol compounds with antioxidant effects in vitro, with main polyphenols are phenolic acids such as chlorogenic and caffeic acid.[27] Caffeine and its metabolites, 1-methylxanthine and 1-methyluric acid, have also been shown to have antioxidant properties.[28] Caffeine has also been reported to inhibit chemical carcinogenesis and ultraviolet B light induced carcinogenesis in mice.[29,30] Coffee is also found to decrease the progression of liver disease among those with advanced hepatic fibrosis[7] and even reduce the risk of HCC[31,32] One study[33] concluded that approximately 2 coffee cup equivalents/day was associated with less severe hepatic fibrosis, but the beneficial effect was only shown in patients with chronic hepatitis C rather than patients with other liver diseases. A case control study in Italy showed that the protective effect of coffee on HCC was mainly in people who are not chronically infected with HBV.[31] Overall, previous studies included mostly chronic hepatitis C patients and HBV patients were underrepresented. Based on our results, it appears that liver fibrosis in chronic hepatitis B patients is determined mainly by virological and genetic factors and less affected by caffeine intake.

In previous reports, men who have daily alcohol intake of 30–39 g and women who consumed 20–29 g of alcohol daily would have an increased risk of all cause mortality among the general population.[34] Seventy-eight percent of our cohort did not drink alcohol at all while only 1% of patient had history of excessive alcohol consumption. Nonetheless, we could not find any deleterious effect of mild to moderate alcohol consumption to liver fibrosis. As alcohol drinkers were mostly coffee drinkers as well, the concomitant caffeine intake might but one of the confounders leading to the absence of increased risk of advanced fibrosis in alcohol drinkers. Nonetheless only a minority (1% of the study population has excessive alcohol intake, we believe that the major reason of the absence of increased risk of advanced fibrosis in alcohol drinkers was the modest instead of excess amount of alcohol use. Because most of our patients had no advanced liver disease as compared with other studies (33, 35–38), our results could not be extrapolated to cirrhotic patients. Less than 20 g of alcohol intake tends not to increase risk of advanced fibrosis in our present study. Controlled prospective studies may be done in the future to verify this.

One of the limitations of our study was the lack of liver biopsy. As liver biopsy is an invasive procedure, studies using histological fibrosis as an endpoint might suffer from the problem of small sample size and selection bias towards patients with active or advanced liver disease.[39] On the other hand, a non-invasive test such as transient elastography could be applied to a large number of patients with different disease severity. In fact, transient elastography has been shown to be highly accurate in detecting histological advanced fibrosis and cirrhosis in chronic hepatitis B patients,[16,23] though the accuracy might be limited in settings of grossly elevated transaminase levels,[16] but not in the presence of steatosis.[18] Secondly, recall bias might occur during the questionnaire survey and affect the accuracy of the measurement of the caffeine intake measured. We have tried to minimize this bias by using a quantity-frequency questionnaire, which has been previously adapted in a study demonstrating the protective effect of coffee consumption from HCC.[11] There were 159 (15.2%) participants drinking >2–3 coffee-cup equivalents/day and 103 (9.9%) drinking >3 coffee-cup equivalents/day. Because the above numbers for these groups were low and previous finding showing 2 coffee-cup equivalents/day was associated to less severe liver fibrosis, we combined these groups for analysis. Because this is a cross sectional study, possible unmeasured as well as poorly measured confounding factors that may affect the interpretation of our data such as changes in the drinking habit of the patients, variability of caffeine intake over time, socioeconomic status, educational level were not considered in our analysis.

In conclusion, cross-sectional caffeine intake does not affect liver stiffness in chronic HBV-infected patients. The protective effect of caffeine on HCC demonstrated in previous studies is probably via the pathway other than reducing liver fibrosis. The prevalence of advanced liver fibrosis is low (20%) in chronic hepatitis B patients with daily alcohol consumption below 20 g.

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