Researchers have found that people who often sleep badly could be more likely to develop non-alcoholic fatty liver disease (NAFLD).
Prof Christopher Byrne from the NIHR Southampton Biomedical Research Centre contributed to the large South Korean study.
The results, published in the Journal of Personalized Medicine, show getting a better night’s sleep may help protect against NAFLD.
Preventing liver disease
NAFLD is the term for a range of conditions caused by a build-up of fat in the liver. Usually seen in people who are overweight or obese, it’s estimated to affect around 25% of the world’s population.
It has four stages, where the liver becomes progressively more damaged. The first stage, steatosis, involves a largely harmless build-up of fat in the liver. Most people do not know they have it.
However, if untreated it can progress to more serious stages. Non-alcoholic steatohepatitis (NASH) sees the liver become inflamed. During fibrosis, scar tissue forms around the liver. Cirrhosis, the final stage, is where the liver becomes permanently damaged and stops working properly.
Overall, 86,530 Korean adults without NAFLD and or liver scarring took part. The researchers assessed their liver health and sleep quality soon after they joined and an average of 3.6 years later.
Participants were asked to complete a survey known as the Pittsburgh Sleep Quality Index at the initial and follow-up sessions. This was used to estimate the amount and quality of their sleep.
Both times they had ultrasound scans to look for a build-up of fat in the liver. These scans use high-frequency sound waves to produce images, and are the same as those used in pregnancy. Participants also had a blood test, which was used to estimate liver scarring.
Sleep quality affects risk
The researchers found 12,127 participants, around 14 percent, had developed steatosis (the first stage of NAFLD). In 559, this had progressed to fibrosis (the third stage).
Participants with persistently poor sleep quality were more likely to develop NAFLD, compared to those who usually slept well. Those who slept an hour or more less or had worse sleep quality at the follow-up session than they did at the start were also more at risk.
Prof Byrne, Professor of Endocrinology and Metabolism at the University of Southampton and Honorary Consultant Diabetologist & Metabolic Physician, said:
“Sleep is extremely important for our health and wellbeing. This large-scale study suggests that prioritising good sleep could be important to help protect against NAFLD, an increasingly common disease.”