Fatty liver disease affects nearly one-third of Australians. In most cases, it will cause no lasting liver health problems, but for the unlucky ones in whom it sets off a prolonged inflammatory response, it is potentially very serious.
Unchecked, the disease can lead to cirrhosis, liver cancer and liver failure, and can ultimately result in death.
While excessive drinking of alcohol is a well-known cause of liver disease, the most common variety is non-alcoholic fatty liver disease. A poor diet is frequently to blame, with obesity, diabetes, and metabolic syndrome the top risk factors.
“Non-alcoholic fatty liver disease (NAFLD) affects 25 per cent of the population,” says Professor Elizabeth Powell, a hepatologist with Queensland Health. “But it’s the inflammatory response to liver injury that can determine the outcome of the injury.”
The most serious type of fatty liver disease, with inflammation and liver cell injury, is known as steatohepatitis. Inflammation is a common factor in the progression of three other key liver diseases: alcoholic hepatitis; and viral hepatitis B and C.
“Inflammation underpins them all,” says Professor Powell. “Persistent inflammation triggers the development of fibrosis – scarring in the liver – and progressive scarring over many years can lead to cirrhosis.”
Patients with cirrhosis are at risk of developing complications of advanced liver disease including hepatocellular cancer – the primary form of liver cancer.
Liver cancer is one of the fastest-growing causes of cancer death in Australia and has one of the poorest prognoses. It has a five-year survival rate of just 16 per cent, a statistic that appalls Professor Powell.
“It is particularly troubling because most liver cancer is potentially preventable if the cause of chronic liver disease is identified early and interventions are undertaken to treat it,” she says.
In the case of viral hepatitis, there are treatments that can cure or suppress the disease before it leads to the more serious problems caused by inflammation. Antiviral therapies can cure hepatitis C in the majority of cases, and long-term treatment of hepatitis B can suppress the virus and reduce liver inflammation.
The good news is that only about five per cent of people with fatty liver develop clinically significant liver disease. The bad news is that there are, so far, no medications to treat it.
“There are a number of problems that we need to address,” says Professor Powell. “The obvious one is the lack of therapies to treat it.
“And the other major issue is the need for biomarkers that can detect which patients are at risk of disease progression. If we had a good biomarker for inflammation, that would be really important to detect the small subset of patients at risk from non-alcoholic steatohepatitis.”
It’s yet another window on the potentially life-changing consequences of better understanding inflammation.
Liver cancer is now one of the fastest-growing causes of cancer death in Australia and has one of the poorest prognoses.
BY THE NUMBERS
Fatty liver disease affects nearly one third of the Australian population