Systematic Review With Meta-analysis

Coffee Consumption and the Risk of Cirrhosis

O. J. Kennedy; P. Roderick; R. Buchanan; J. A. Fallowfield; P. C. Hayes; J. Parkes

Disclosures

Aliment Pharmacol Ther. 2016;43(5):562-574. 

In This Article

Abstract and Introduction

Abstract

Background Liver cirrhosis is a large burden on global health, causing over one million deaths per year. Observational studies have reported an inverse association between coffee and cirrhosis.

Aims To perform a systematic review and meta-analysis to characterise the relationship between coffee consumption and cirrhosis.

Methods We searched for studies published until July 2015 that reported odds ratios, relative risks (RR) or hazard ratios for cirrhosis stratified by coffee consumption. We calculated RRs of cirrhosis for an increase in daily coffee consumption of two cups for each study and overall. We performed analyses by study design, type of cirrhosis and mortality. We assessed the risk of bias in each study and the overall quality of evidence for the effect of coffee on cirrhosis.

Results We identified five cohort studies and four case–control studies involving 1990 cases and 432 133 participants. We observed a dose–response in most studies and overall. The pooled RR of cirrhosis for a daily increase in coffee consumption of two cups was 0.56 (95% CI 0.44–0.68; I 2 83.3%). The RR pooled from cohort studies for a daily increase of two cups was 0.58 (95% CI 0.41–0.76; I 2 91.1%) and from case–control studies it was 0.52 (95% CI 0.40–0.63; I 2 0.0%). The pooled RR of alcoholic cirrhosis for a daily increase of two cups was 0.62 (95% CI 0.51–0.73; I 2 0%) and of death from cirrhosis it was 0.55 (95% CI 0.35–0.74; I 2 90.3%).

Conclusion This meta-analysis suggests that increasing coffee consumption may substantially reduce the risk of cirrhosis.

Introduction

Liver cirrhosis is a significant burden on global health. Between 1980 and 2010, the number of deaths worldwide from cirrhosis increased from around 676 000 (1.54% of total) to over one million (1.95% of total).[1] Cirrhosis is also an important cause of disability and morbidity, and in 2010 was responsible for 31 million disability-adjusted life years (1.2% of the total). Although the absolute number of deaths from cirrhosis has increased, the global age-adjusted mortality rate decreased by 22% between 1980 and 2010. Trends in mortality rates vary markedly between countries, however, due to varying exposure to risk factors and the availability of vaccinations and treatments. In some countries, such as India and the UK, mortality rates are increasing.[1] The risk factors and aetiologies of cirrhosis are diverse, but those traditionally considered as important include alcohol-related liver disease and chronic viral hepatitis. More recently, and as a result of increases in obesity and diabetes mellitus, non-alcoholic fatty liver disease (NAFLD) has also emerged as a significant aetiological factor.[2,3] Irrespective of aetiology, cirrhosis develops by a common mechanistic pathway involving chronic inflammation of the liver, followed by fibrosis, leading to end-stage liver disease (cirrhosis), which can be fatal either due to complications related to portal hypertension (decompensation) or to hepatocellular carcinoma (HCC).

Coffee is ubiquitous in most societies. Coffee comprises over a thousand compounds, many of which are biologically active and may affect human health. These include caffeine, chlorogenic acid, melanoids and the pentacyclic diterpenes, kahweol and cafestol.[4] The biological effects of coffee include stimulation of the central nervous system, primarily by caffeine, the attenuation of oxidative stress and inflammation, and anti-carcinogenesis.[5] Due to its widespread consumption, coffee and its effects on health have been studied extensively. In the context of liver disease, coffee appears to confer a number of protective effects. Animal studies and human observational studies suggest that coffee consumption reduces the frequency of abnormal liver function tests, fibrosis, cirrhosis and HCC.[6–10] In addition, a randomised-controlled trial (RCT) showed that patients with hepatitis C who drank more coffee had lower serum levels of liver enzymes.[11] The aim of this meta-analysis was to summarise the evidence from studies on the effect of coffee on cirrhosis.

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