GWAS Identifies Gene Regions Associated with Sleep Duration

A study published today in Nature Communications has identified 76 new gene regions associated with sleep duration.

“While we spend about a third of our life asleep, we have little knowledge of the specific genes and pathways that regulate the amount of sleep people get,” says Hassan Saeed Dashti of Massachusetts General Hospital. “Our study suggests that many of the genes important for sleep in animal models may also influence sleep in humans.”

It is well understood that regularly getting adequate sleep is important to health, and both insufficient sleep (6 or fewer hours) and excessive sleep (9 hours or more) have been linked to significant health problems. Family studies have suggested that from 10% to 40% of variation in sleep duration may be inherited.

The current genome-wide association study (GWAS) analyzed genetic data from more than 446,000 participants in the U.K. Biobank who self-reported the amount of sleep they typically received. It identified 78 gene regions that are associated with sleep duration, two of which were already known. Participants carrying only a single gene variant tended to differ in average amount of sleep by a minute, while participants carrying the largest number of duration-increasing variants reported an average of 22 more minutes of sleep compared to those with the fewest.

To confirm the accuracy of findings based on self-reported sleep duration, the researchers tested the 78 duration-associated variants in a subgroup of participants who had worn motion-detecting devices called accelerometers for up to a week. These devices allowed for objective measurement of sleep duration and consideration of factors like sleep efficiency, waking up during the night, and daytime inactivity.

Since both shorter- and longer-than-average sleep duration have been associated with health problems, the team conducted separate GWASs for participants who reported short or long sleep duration. Those studies identified additional genes not identified in the larger group analysis that contributed to either longer or shorter sleep duration. The researchers also found shared genetic links between both short and long sleep duration and factors such as higher levels of body fat, depression symptoms, and fewer years of schooling. In addition, short sleep duration was genetically linked with traits such as insomnia and smoking, while long-duration variants were linked with schizophrenia, type 2 diabetes, and coronary artery disease.