Dozing: A New Stroke Risk Factor?

Nodding Off Throughout the Day Linked to Increased Risk of Stroke

From the WebMD Archives

Feb. 21, 2008 (New Orleans) -- Older people who nod off throughout the day have more than four times the risk of stroke as those who don't doze, a new study suggests.

Daytime dozing also appears to raise the chance of having a heart attack or dying of a heart attack or stroke, the researchers say.

But don't worry about a nap or two. "This is significant dozing" -- nodding off frequently and unintentionally while watching TV or reading during the day, says researcher Bernadette Boden-Albala, PhD, of Columbia University in New York.

Previous research has shown that people who have sleep apnea, brief periods when breathing stops during sleep, are at increased risk of stroke.

But Boden-Albala says this is one of the first studies to look at the association between unplanned daytime dozing and stroke.

Daytime Dozing Raises Stroke Risk

The researchers studied more than 2,100 adults with an average age of 73. They were asked how often they fell asleep during specific daytime situations, such as watching TV, sitting and talking to someone, or stopping in traffic.

Based on their responses, 9% were classified as being significant dozers, 47% as moderate dozers, and 44% as no-dozers.

Over the next two years, there were 127 vascular events such as strokes, heart attacks, or deaths from them.

Among the findings, presented at the American Stroke Association's (ASA) International Stroke Conference:

  • The risk of stroke was 2.6 times greater for moderate dozers than for people who didn't unintentionally fall asleep during the day.
  • Significant dozers had a 4.5-fold higher risk of stroke, compared with no-dozers.
  • The risk of a heart attack or dying of vascular disease was also higher -- 1.6% for moderate dozers and 2.6% for significant dozers.

The findings held up even when the researchers took into account other stroke risk factors such as high blood pressure, diabetes, physical activity, obesity, and socioeconomic status.

Sleep Problems Treatable

So just what makes someone a significant dozer? According to Boden-Albala, "This might be someone who always falls asleep while watching TV, always falls asleep while sitting and reading, and sometimes falls asleep while sitting on the couch.

"But it's cumulative, so someone who falls asleep about 50% of the time during all three situations" would also be a significant dozer, she says.

If you have trouble staying awake throughout the day, talk to your doctor, Boden-Albala says.

"It could be apnea, or depression, or a thyroid problem. You need to be aware that disturbed sleep is a problem," she tells WebMD.

Sleep apnea -- "or just about any sleep disorder" -- is treatable, adds ASA spokesman Daniel Lackland, MD, a stroke expert at the Medical University of South Carolina in Charleston.

"And if you treat the disorder successfully, you can reduce or even eliminate the increased stroke risk," he tells WebMD.

WebMD Health News Reviewed by Louise Chang, MD on February 21, 2008



International Stroke Conference 2008, New Orleans, Feb. 20-22, 2008.

Bernadette Boden-Albala, PhD, Columbia University, New York.

Daniel Lackland, MD, ASA spokesman; professor of epidemiology, Medical University of South Carolina, Charleston.

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