Top risk of stroke for normal-weight adults: Getting under 6 hours of sleep

Habitually sleeping less than six hours a night significantly increases the risk of stroke symptoms among middle-age to older adults who are of normal weight and at low risk for obstructive sleep apnea (OSA), according to a study of 5,666 people followed for up to three years.

The participants had no history of stroke, transient ischemic attack, stroke symptoms or high risk for OSA at the start of the study, being presented today at SLEEP 2012. Researchers from the University of Alabama at Birmingham recorded the first stroke symptoms, along with demographic information, stroke risk factors, depression symptoms and various health behaviors.

After adjusting for body-mass index (BMI), they found a strong association with daily sleep periods of less than six hours and a greater incidence of stroke symptoms for middle-age to older adults, even beyond other risk factors. The study found no association between short sleep periods and stroke symptoms among overweight and obese participants.

"In employed middle-aged to older adults, relatively free of major risk factors for stroke such as obesity and sleep-disordered breathing, short sleep duration may exact its own negative influence on stroke development," said lead author Megan Ruiter, PhD. "We speculate that short sleep duration is a precursor to other traditional stroke risk factors, and once these traditional stroke risk factors are present, then perhaps they become stronger risk factors than sleep duration alone."

Further research may support the results, providing a strong argument for increasing physician and public awareness of the impact of sleep as a risk factor for stroke symptoms, especially among persons who appear to have few or no traditional risk factors for stroke, she said.

"Sleep and sleep-related behaviors are highly modifiable with cognitive-behavioral therapy approaches and/or pharmaceutical interventions," Ruiter said. "These results may serve as a preliminary basis for using sleep treatments to prevent the development of stroke."

Ruiter and colleagues collected their data as part of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, led by George Howard, PhD, of the University of Alabama at Birmingham School of Public Health. REGARDS enrolled 30,239 people ages 45 and older between January 2003 and October 2007, and is continuing to follow them for health changes. The study is funded by the National Institutes of Health (NIH) National Institute of Neurological Disorders and Stroke.