Epidemiology and natural history of alcoholic liver disease

Alcohol represents the oldest substance of abuse known, existed at least as early as the Neolithic period. In the present era, almost half of the world’s population consumes alcohol and it represents the third largest risk factor for disease and disability and the most prevalent cause of advanced liver disease worldwide. In fact, when alcohol consumption reaches "unsafe quantities" an Alcoholic Liver Disease (ALD) is very likely. ALD comprises a large spectrum of diseases, ranging from simple steatosis to steatohepatitis with fibrosis and cirrhosis. Alcohol related cirrhosis is responsible of almost 50% of all cirrhosis-related and 1% of all-cause deaths worldwide. Even if ALD and alcoholic cirrhosis represent a large part of liver diseases, to know exactly the global burden of these phenomena is very difficult. This is mostly due to diagnostic and nosological issues, being ALD represented by several types of diseases and the diagnosis very often based on voluntary questionnaires. Also the natural history of ALD is somewhat difficult to predict, since there is not a definite evolution between the various stages of the disease and, indeed, they may coexist in a single subject. In this brief review we will report on the global burden of ALD, the principal factors influencing its prevalence among populations and the different presentations of its natural history.