Researchers found a strong association with daily sleep periods of less than six hours and a greater incidence of stroke symptoms for middle-aged to older adults, even beyond other risk factors

Sleeping less than six hours a night habitually ups the risk of stroke among middle-aged people and old adults despite having normal weight and low risk of obstructive sleep apnea (OSA), researchers from the University of Alabama at Birmingham found out. However, the study found no link between short sleep periods and stroke symptoms among overweight and obese participants.

Megan Ruiter, lead author of the study, said, “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. 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.”

The study was released at SLEEP 2012, which examined 5,666 people and all of them were followed for up to three years. At the start of the study, participants had no history of stroke, transient ischemic attack, stroke symptoms or high risk for OSA. Researchers recorded the first stroke symptoms, along with demographic information, stroke risk factors, depression symptoms and various health behaviours. SLEEP is an annual event, organised jointly by the American Academy of Sleep Medicine and the Sleep Research Society, which brings together leading clinicians and scientists in the fields of sleep medicine and sleep research.  

According to the researchers, 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-aged to older adults, even beyond other risk factors.

Ms Ruiter believes that further research may support the results. It would also provide 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.

“Sleep and sleep-related behaviours are highly modifiable with cognitive-behavioural therapy approaches and/or pharmaceutical interventions. These results may serve as a preliminary basis for using sleep treatments to prevent the development of stroke,” she explains.

In statement released by American Academy of Sleep Medicine, Ms Ruiter and her 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 of 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.