Inadequate sleep has been linked to nonalcoholic fatty liver disease (NAFLD), but studies on the association have yielded inconsistent results. This prompted researchers at the National Institutes of Health to study whether short sleep duration could be a risk factor for nonalcoholic fatty liver disease.
As researchers of the 2016 review pointed out NAFLD has become the most common cause of chronic liver disease in the West. Although the primary risk factors for NAFLD are abdominal obesity and insulin resistance, other risk factors include:
Researchers performed a systematic review and meta-analysis of studies that reported the risk of NAFLD among people with short sleep duration. Half of the studies defined short sleep duration as less than five hours of sleep and one third defined short sleep duration as less than six hours.
The review found that there was a small, but significantly increased risk of NAFLD among those with short sleep duration compared to those with longer sleep duration.
What is the link between NAFLD and short sleep duration?
This review didn't reveal why such a link appears to exist. However, the authors did have some suggestions:
1. Inflammatory cytokines
Cytokines act as chemical messengers within the body. Studies have found cytokines involved in the body's inflammatory response, such as interleukin-6 and tumor necrotic factor alpha, play an active role in the development of NAFLD and are associated with insufficient sleep.
2. Increased appetite and less exercise
Insufficient sleep can increase appetite and hunger cravings, which can increase obesity risk — a known risk factor for NAFLD. Furthermore, sleep deprivation often leads to fatigue, making exercise less appealing.
3. Stress hormones
Studies have found that stress hormones, such as cortisol are associated with abnormal sleep patterns and sleep issues, such as insomnia. Cortisol is also connected to insulin resistance — a primary risk factor for NAFLD.
Can sleep deprivation cause NAFLD?
The review could only demonstrate an association between short sleep duration and NAFLD. It could not show why.
Although it appears that short sleep duration may increase risk of NAFLD, it's possible that short sleep duration may be a consequence of NAFLD, rather than a risk factor for the disease.
If you have any concerns about the quality of your sleep or the health of your liver, speak with your doctor.
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Martin is the creator of Insomnia Land’s free insomnia sleep training. His online course uses CBT techniques to teach participants how to sleep better without relying on sleeping pills. More than 5,000 insomniacs have completed his course and 97 percent of graduates say they would recommend it to a friend.