Fatty Liver: It Is Not Just About The Liver

Article by Dr Desmond Wai

Fatty Liver: It Is Not Just About The Liver

Dr Desmond Wai

National University of Singapore Faculty of Medicine
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Non Alcoholic Fatty Liver Disease (NAFLD) is diagnosed clinically, when fatty infiltration of the liver is demonstrated on imaging like ultrasonography, or on histology, with secondary causes such as alcohol, drugs etc. excluded. The limit of alcohol has been defined as 21 units or more per week in male, or 14 units or more per week in female. NAFLD is associated with the metabolic syndrome. Most NAFLD patients have at least one of the following: central obesity, dyslipidemia, hypertension, or diabetes mellitus.

NAFLD is a slowly progressive disease. Its pathogenesis is believed to be due to insulin resistance, followed by a “2-hit” process. First, with insulin resistance, fat is infiltrated into the liver, causing hepatic steatosis. Subsequently, the fat undergoes oxidation, causing damage like inflammation, fibrosis, and may even lead to liver cirrhosis or hepatocellular carcinoma.
Though no local prevalence studies are available, recent studies in HK and Shanghai showed about 27 to 38% of the general public have NAFLD. In my clinical practice, NAFLD is often diagnosed during multiphasic health screening and most patients are asymptomatic. 
Over the last 20 years, many studies have shown that NAFLD is not a benign disease. NALFD has been shown to lead to liver cirrhosis and hepatocellular carcinoma (HCC). What we label 
as “Cryptogenic cirrhosis” in the past may actually be caused by NAFLD. Patients with NAFLD also have a 55-86% increase risk in mortality as compared to the general public. 
Interestingly, the 2 major causes of death of NAFLD are actually non-hepatic malignancy and coronary artery disease (CAD). In epidemiological studies, obesity has been linked to cancer in the colon, breasts, pancreas, endometrium, etc. The actual pathogenesis of this obesity-cancer link is still not well understood. It is not surprising that NAFLD is linked to CAD as both share the same risk factors. Another interesting research finding is that over a long-term follow up, NAFLD patients will develop more and even all components of the metabolic syndrome.
Many therapeutic studies have attempted to find the best medication for NAFLD. Unfortunately, there is currently no ideal drug. Medications like lipid-lowering drugs, insulin sensitizers, 
antioxidants, and supplements have been tested in various trials and to date, only vitamin E at 800 IU/day has been shown to be effective in non-diabetic NAFLD patients. But as other studies have shown that high dose vitamin E may increase all-cause mortality, many gastroenterologists are still cautious in prescribing it. 
The best treatment for NAFLD is weight loss. 5% weight loss can improve hepatic steatosis while a 10% weight loss can improve hepatic inflammation. But how to make a NAFLD patient lose weight is yet another big topic for discussion.
To sum up, NAFLD is a common disease, affecting 20-30% of our population. While it may lead to liver cirrhosis and HCC, it is also related to non-hepatic malignancy and ardiovascular 
disease. Management strategy should include excluding secondary causes, screening for all components of the metabolic syndrome, and lifestyle and dietary modifications. In patients with persistent hepatic inflammation, or complications like cirrhosis, they should be referred to a gastroenterologist for further evaluation and treatment.
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