Liver diseases are now a newer common global health concern. Fatty liver reserves its place in the setting of non-alcoholic fatty liver disease (NAFLD) as well as alcoholic liver disease (ALD), although the pathogenesis of accumulation of the excess fat being different in both conditions. Fatty liver is causing most of the liver disease burden worldwide and is known to be intimately associated with a globalized economy and a switch to a westernized lifestyle. An increase in a sedentary lifestyle, consumption of calories dense diet aids to facilitate the development of NAFLD while a vogue of alcohol culture in the earlier age and an increased amount of per capita alcohol consumption has aided to the increased prevalence of ALD globally.

A few individuals with NAFLD may develop progressive liver disease, characterized by hepatocyte injury (ballooning), inflammation and finally, fibrosis, ultimately known as non-alcoholic steatohepatitis (NASH).

The non-availability of a disease-specific, powerful and simple biomarker for large scale population-based studies remains the red flag in the epidemiology of NAFLD. .NAFLD, NASH and fibrosis etc are largely histologically defined and thus possesses great difficultly to be estimated epidemiologically. Non-invasive serum markers, various imaging modalities like magnetic resonance (MR), has been used in the past for an assessment of the burden of clinically relevant NAFLD, but the lack of uniformity, standardization of serum markers across populations and wide acceptance in epidemiological studies limits their use.

Since MRI and transient elastography, besides having fair precision and reproducibility, are difficult to use in large scale epidemiological settings due to the cost, limited availability and lack of expertise, most of the available epidemiological data on NAFLD are ultrasound-based that detect liver fat in a semi-quantitative manner. Many studies have also utilized ALT despite its’ nonspecific nature in view of its’ simplicity and wide availability. In general, studies utilizing abnormal liver blood tests for rendering NAFLD diagnosis have reported much lower prevalence estimates contrasting studies utilizing the imaging methods.

The exact incidence of ASH yet not known as biopsy remains the gold standard for diagnosis, while most previous studies utilized diagnostic coding which is inherently less accurate. Estimates indicate an increase in the incidence of ASH in both males and females.

Adverse health outcomes in NAFLD and ALD are not only because of progressive liver fibrosis (the most significant factor for liver-related and all-cause mortality) yet also by non-liver (cardiovascular, cancer, accidents, neurological) clinical outcomes that demands a multidisciplinary and social approach to these conditions.

WHO targeted a reduction in mortality from ALD cirrhosis to <3.2/100,000 population by the year 2020, but it is yet to be achieved. Since alcohol plays a major role in its aetiology, curbing the sale of alcohol by cost-effective policy decisions can significantly decrease overall and liver-related mortality attributable to alcohol. It can be done through a systematic increase in taxation, minimum unit price, advertising restrictions, marketing regulations, low-level interventions from clinicians, awareness campaigns, labelled health warnings and protection of children from alcohol and alcohol-promoting advertisements.

Abstinence helps in a great way to decrease the risk of progression and complications. Early stages of ALD can be reverted with abstinence, depicting the importance of screening for harmful alcohol intake during the primary contact with the patient.

The National Institute on Alcohol Abuse and Alcoholism (NIAAA) recommends questioning “How many times in the past year have you had 5 or more drinks in a day (for men) or 4 or more drinks in a day (for women)?” during screening, followed by complete AUDIT in patients with a positive response.

Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) highlights no safe limits for alcohol consumption, which has also been highlighted in a recent UK guideline. Thus “complete abstinence” should be the evidence-based advice in the clinics. However, in cases of sociocultural restrictions or stubbornness intake should be limited to ≤2 drinks/day in females and ≤3 drinks/day in males with each drink being containing 10 grams of alcohol.

Source-Mitra S, De A, Chowdhury A. Epidemiology of non-alcoholic and alcoholic fatty liver diseases, TGH, 2020;5