A new study clearly establishes a partial genetic basis underlying racial differences in slow-wave sleep

Using a panel of 1,698 ancestry informative genetic markers, the study found that greater African genetic ancestry was associated with lower amounts of slow-wave sleep in African-American adults. African ancestry explained 11% of the variation in slow-wave sleep after adjustment for potential confounders. "Our data are the first to show that race differences in slow-wave sleep may have an independent and significant genetic basis," said senior author Martica Hall, professor of psychiatry at the University of Pittsburgh. Led by Hall and lead author Indrani Halder, the research team analyzed data from a community-based sample of 70 African-American adults and 101 European Americans with a mean age of about 60 years. Objective sleep data were gathered by polysomnography. Blood samples for genotyping were collected, and DNA was isolated following standard protocols. African-Americans have varying proportions of genetic admixture and exhibit a wide range of African genetic ancestry. Among African-American study participants, percentage of African ancestry ranged between 10% and 88%, with a mean of 67%.