Previous research has shown that people with poor sleep quality are at risk of developing fatty liver disease. A new study reports that the reverse also holds true—people with non-alcoholic fatty liver disease (NAFLD) may have worse sleep quality, according to results published in the journal BMC Public Health.

Arising from the accumulation of fat in the liver, NAFLD and its more severe form, non-alcoholic steatohepatitis (NASH), are responsible for a growing proportion of advanced liver disease worldwide. As a result of inflammation, NAFLD can lead to the buildup of scar tissue (fibrosis), cirrhosis and even liver cancer. With no effective approved medical therapies, disease management is dependent on lifestyle changes such as weight loss and exercise.

People with NAFLD have been found to sleep for shorter periods of time. Elaheh Zarean, of Shahrekord University of Medical Sciences in Iran, and colleagues studied the association between sleep duration, sleep quality and NAFLD in an Iranian population.

The sample population included 9,151 people—including 1,320 with NAFLD—from the Shahrekord Prospective Epidemiological Research Studies in Iran (PERSIAN) Cohort Study.

The researchers found that people with NAFLD went to bed later, woke up later and slept for shorter spans. What’s more, they had worse sleep efficiency, a ratio of time spent asleep and the total time set aside for sleeping. These individuals were also more likely to take daytime naps and use sleeping pills.

Even after controlling for sociodemographic, clinical and biological factors, NAFLD was linked to worse sleep efficiency and higher sleeping pill usage. Frequent daytime napping was observed in men but not women. The link between fatty liver disease and sleep efficiency was stronger in people over 60 years of age and those between ages 40 and 60 compared with people under 40.

“Diagnosis of NAFLD is associated with several poor sleep characteristics in middle-aged Iranians,” wrote the researchers. “Although longitudinal studies would help to clarify the direction of causality, our study shows that poor sleep is an important aspect of NAFLD.”

Click here to read the study in BMC Public Health.

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