If you own a white noise machine, sleeping mask or high-tech mattress, you may feel like you’re in control of your sleep. But what if there were factors outside your control that influence how many hours of sleep you get every night?
In addition to environmental factors like temperature, noise and light, our genes are known to play a role in determining the quantity and quality of sleep, though the specifics have remained unclear.
In the largest genetic study of its kind, a team at Massachusetts General Hospital’s Center for Genomic Medicine (CGM), led by Hassan Dashti, PhD, RD, a postdoc in the Saxena lab, has expanded our understanding of how genetics impact sleep duration and risk for disease. The results could lead to new treatments for conditions such as insomnia, schizophrenia and obesity.
Identifying which genes impact sleep duration
Investigators have already identified a few genetic mutations that impact sleep by altering the connections between neurons in the brain.
In their study, the (CGM) team analyzed the genetics of nearly 450,000 people who had participated in the UK Biobank. Specifically, they looked at the participants’ self-reported data regarding how many hours of sleep they get each night. While previous studies have relied solely on this self-reported data, Dashti and the team also validated the data with an accelerometer device which provided an objective measure of sleep duration.
The team found that genetic variants that have already been identified only partially accounted for the differences in participants’ sleep habits. They identified 76 additional genetic variants that are involved in brain development, long-term depression, and neurotransmission that also determine how long someone will sleep. The team confirmed these findings using data from three additional studies, including the Partners Healthcare Biobank.
Although individually each of these 76 variants only have a small impact on sleep duration, the data taken together can collectively tell researchers a lot about an individual’s sleep patterns.
Links between genetics, sleep, and disease
Based on their results, the team also found genetic connections between sleep and both mental and physical health.
Short and long sleep duration were associated with a larger waist and waist-to-hip ratio, suggesting that deviating from the recommended 7-9 hours of sleep per night may increase risk for obesity. They also found links between longer sleep duration and schizophrenia.
If you’re having trouble sleeping at night and can’t figure out why, the answer may not be one thing but a variety of factors. By learning more about the genetics of sleep, researchers hope to develop new drugs and behavior strategies that will help you gain the benefits of a good night’s sleep.