Insufficient, irregular and poor-quality sleep is associated with many chronic conditions, including obesity, atrial fibrillation, hypertension, major depressive disorder and generalized anxiety disorder. Those were the main conclusions of a study recently published in the journal Nature Medicine from corresponding author Evan Brittain, MD, MSCI, professor of Medicine.
Unlike prior research, which relied on cross-sectional and self-reported survey data or polysomnograms, the study used objectively measured, longitudinal sleep data from commercial wearable devices linked to electronic health record data from the National Institutes of Health’s All of Us Research Program. It is the largest study to date using this method.
“It’s a departure from most of the literature,” Brittain said. “We had a really unique opportunity to understand sleep hygiene and health over a very long period of time in a large population.”
He said the study shows that by getting enough sleep and reducing variability around sleep onset and wake times, patients can reduce the incidence of chronic disease. The insights gained from the research may inform clinical guidance around sleep to promote good health.
The study examined 6,875 individuals who wore Fitbit devices and collected sleep data for at least six months, along with their linked electronic health records. Because of inherent limitations in available data, the median age of participants was 50 years old, 71% were female, 84% identified as white, and 71% had a college degree. The studied individuals tracked sleep with wearable devices for a median of nearly 4 ½ years.
The trove of wearable device-linked electronic health data in the All of Us Research Program allowed researchers to look at the links between sleep and a host of conditions, Brittain said, not just one or two.
Researchers found that the less rapid eye movement (REM) and deep sleep study participants got, the more likely they were to develop atrial fibrillation. The more irregular the participants’ sleep, the greater their odds for obesity, hyperlipidemia, hypertension, major depressive disorder and generalized anxiety disorder.
“Every aspect of sleep is important,” Brittain said, “The major takeaway of the study for me was the more regular your sleep pattern is the healthier you’re likely to be.”
The study also suggested that people may need less sleep each night than traditionally recommended. Surprisingly, Brittain said, the study showed that seven hours was the median amount of sleep needed for good outcomes, rather than the minimum amount, as previously thought.
“It probably matters less whether you’re getting eight hours of sleep than the consistency of what time you go to bed and when you wake up,” Brittain said. “That seems to be the most important aspect of this. That is practical advice I can offer my patients,” he said.
The study’s other Vanderbilt authors were Jeffrey Annis, PhD, Hiral Master, PT, PhD, MPH, Lide Han, PhD, Peyton Coleman, Stacy Desine, MSc, and Douglas Ruderfer, PhD.
The study was supported by National Institutes of Health grants R21HL172038, R61/R33HL158941 and R01FD007627.
