An estimated one in five young adults in the United Kingdom have non-alcoholic fatty liver disease (NAFLD), and 1 in 40 have already developed fibrosis (scarring) of the liver.

NAFLD and its more severe form, non-alcoholic steatohepatitis (NASH), are a growing cause of serious liver disease, including cirrhosis (the most advanced stage of fibrosis), liver cancer and the need for a liver transplant.

Researchers from the University of Bristol conducted the first study to attempt to establish the prevalence of fatty liver disease and fibrosis in young healthy adults in the United Kingdom. Publishing their findings in The Lancet Gastroenterology & Hepatology, they analyzed data on a sample of 4,021 participants recruited through the Avon Longitudinal Study of Parents and Children (ALSPAC). The study is also known as the Children of the 90s study.

The ALSPAC, based in Bristol, initially assessed the participants for NAFLD when they were teenagers. This new study reassessed the young people for the liver disease. At this point, they were 24 years old on average.

Looking at the participants who did not report harmful levels of alcohol use, the study authors found that one fifth had fatty liver disease. When looking at all the participants, more than 20% had evidence of fatty liver, and 1 in 40 had fibrosis. Nine people had already developed cirrhosis.

Those young people who consumed a harmful level of alcohol and had fatty liver disease were the most likely to have fibrosis.

After controlling for excessive alcohol consumption, social class and smoking, the study authors found that having a body mass index (BMI) in the obese range (over 30) was associated with a 27.3-fold increased risk of fatty liver and having a BMI in the overweight range (25 to 29.9) was associated with a 5.2-fold increased risk.

After controlling for smoking and social class, the researchers found that having alcohol use disorder and fatty liver was associated with a 4.0-fold increased risk of fibrosis.

"Children of the 90s data has highlighted the potential importance of liver health amongst young adults,” the study’s lead author, Kushala Abeysekera, MBBS, of the University of Bristol, said in a press release. “This age group remains a blind spot for clinicians, as they are typically considered a ‘healthy’ age group that are rarely studied. If the obesity epidemic and culture of alcohol abuse aren’t tackled nationally, we may see increasing numbers of patients presenting with end-stage liver disease, and at earlier ages.”

Abeysekera continued: “It is important to note that whilst we identified that 20% of the cohort had fatty liver. only a small percentage of the individuals will go on to develop cirrhosis (irreversible liver scarring), and the vast majority of participants should be fine if they manage their diet and exercise appropriately.”

To read the study, click here.

To read a press release about the study, click here.