Last month, news of Deputy Speaker of Parliament Charles Chong undergoing a liver transplant took many people by surprise.

Three years ago, the MP for Punggol East, 63, was diagnosed with a severe form of non-alcoholic fatty liver disease(NAFLD) –steatohepatitis– but did not make it public.

While NAFLD is an unfamiliar term to most people, a recently released study by SingHealth doctors found that its incidence is rising in Singapore, and could well be affecting half of the adults here.

This could put more people at risk of liver failure or cancer, the main causes of which are hepatitis or heavy alcohol use. But the damage caused by NAFLD is similar.

Professor Pierce Chow, the lead doctor in the study, said it suggested that the rate here could be higher than the Asian average of about 30 per cent of adults.

While the causes of the disease are not clear, people with NAFLD tend to have hypertension and high cholesterol levels – the same risks for heart disease, diabetes and obesity.

The study looked at Singapore General Hospital patients who had surgery to remove their gall bladder, a pear-shaped organ that sits next to the liver, for the periods 2001 to 2004 and 2011 to 2014.

From the pre-operative scans of the earlier group of 127 patients, 40 per cent had NAFLD. Ten years later, 57 per cent of the 99 patients had it. More patients in the latter group also had high levels of cholesterol– 46 per cent versus 19 per cent.

Almost half of the patients in both groups had high blood pressure.

The study, published online on Dec 20 prior to a print version by the Singapore Medical Journal, said it was “a significant increase” and that intervention is needed to prevent NAFLD’s progression to more advanced liver disease such as liver cirrhosis (hardening) and hepatocellular carcinoma (liver cancer).

Prof Chow said fatty liver disease is a growing concern inmany developed countries that face increasing obesity. In the United States, NAFLD is the third most common cause of liver cancer after hepatitis and alcoholic liver disease.

Because it has no symptoms, NAFLD is rarely discovered until much damage has been done.

Researchers also found that the more obese the person, the higher the risk of having a fatty liver. Indians also appear to be at higher risk.

According to the National University Hospital, which carries out the bulk of liver transplants here,“common causes of liver failure include hepatitis B, cirrhosis, cancer and autoimmune disease”.

There are about 60 people waiting for a liver transplant, about five times the number 10 years ago. Last year, 38 people had such transplants.