April 8th, 2010
12:10 AM ET

Sleep apnea boosts stroke risk

By Val Willingham
CNN Medical Producer

Obstructive sleep apnea, a condition in which breathing stops intermittently during sleep - is associated with an increased risk of stroke in middle-aged or older Americans, especially in men, according to a new study out of the American Journal of Respiratory and Critical Care Medicine. And that's a scary statistic, since, according to the National Sleep Foundation, 18 million people in the U.S. suffer from sleep apnea and many of them don't know it.

Researchers compiled data from the famous Sleep Heart Health Study and looked at stroke risk in 5,422 participants aged 40 years and older without a history of stroke. At the start of the study, participants performed a standard at-home sleep test that determined whether they had sleep apnea and, if so, the severity of the sleep apnea. Participants were followed for an average of nine years. During that period, a total of 193 participants had a stroke – 85 men (of 2,462 men enrolled) and 108 women (out of 2,960 enrolled).

Study investigators found that the increased risk of stroke appeared in men with mild sleep apnea. Their risk of stroke rose if the apnea was more severe. Men with moderate to severe sleep apnea were nearly three times more likely to have a stroke than men without sleep apnea or with mild sleep apnea. But in women it was different. The increased risk of stroke in females was significant only with severe levels of sleep apnea. The increased risk of stroke from sleep apnea depended on other risk factors the women had such as weight issues, smoking, race, diabetes and high blood pressure.

People who have sleep apnea can have one or more pauses in breathing or shallow breaths while they sleep. It can also be accompanied with loud snoring, or snorting. The pauses often occur five to 30 times an hour. Many times the sleeper is disrupted during the night, because of odd breathing habits, which can result in excessive daytime sleepiness. The erratic sleeping/breathing pattern can also put serious stress on the heart, because the pauses cause the flow of oxygen to the vital organs to slow or even stop for a few seconds, which makes the heart pump harder.

"And what's even more alarming, is that the body becomes used to these erratic patterns, even if we are not sleeping," says Michael J. Twery, Ph.D., director of the NIH National Center on Sleep Disorders Research "And when that happens you have stress on the heart all the time. The effects from sleep apnea start to erode your health and that can eventually lead to stroke."

Researchers believed that because men are more prone to have sleep apnea earlier in life, the risks of stroke are much higher than in women, who usually suffer from sleep apnea when they are pregnant, overweight or are already going through menopause.

"It’s possible that the stroke risk is related to cumulative effects of sleep apnea adversely influencing health over many years,” said Susan Redline, M.D., MPH.

"Our findings provide compelling evidence that obstructive sleep apnea is a risk factor for stroke, especially in men," said Susan Redline, M.D., M.P.H., professor of medicine, pediatrics, and epidemiology and biostatistics, at Case Western Reserve University in Cleveland, Ohio, and lead author of the paper. "Overall, the increased risk of stroke in men with sleep apnea is comparable to adding 10 years to a man's age. Importantly, we found that increased stroke risk in men occurs even with relatively mild levels of sleep apnea.”

Because sleep apnea symptoms happen at night, when the patient is asleep, many don't realize they are affected and can go years, even a lifetime, suffering from the condition and not knowing it.

So how do you know if you have sleep apnea, or just a snoring problem? Sleep experts recommend that if you have a partner who notices you are snoring heavily and gasping for breath as you sleep, or you wake up in the morning and find you can't function during the day, because you a sleepy, it's best to talk to you doctor. Prior studies have shown that sleep apnea can be a precursor to hypertension, weight gain, diabetes, as well as heart disease and stroke. It is also linked to excessive daytime sleepiness, which lowers performance in the workplace and at school, and increases the risk of injuries and death from drowsy driving and other accidents.

"It's really up to the patient to make the first move, to go to the doctor and ask to be tested.” explains Twery, "There are a lot of treatments out there that can help. And people need to follow them. Because sleep apnea has no pain with it, many people think it can't hurt them. But research shows, that sleep apnea can and will hurt your body, especially if it goes undetected."

The next step for this project? Researchers will start clinical trial studies that can help scientists determine if treating sleep apnea can lower a person's risk of stroke and other diseases.

Editor's Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

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Filed under: Heart • Sleep

soundoff (12 Responses)
  1. momu

    When it says stroke, does it refer to brain stroke or heart stroke?

    My father has a terrible (scary) apnea for as long as I remember.
    He had a couple of brain strokes on the last 5 years.

    April 9, 2010 at 06:01 | Report abuse | Reply
  2. Dr.D11

    Sleep Apnea is a serious matter.Dangerous at times.
    One must exercise a good"Sleep Hygene".Ask your doctor about it.Read about it.Sleeping pills is a:"No No".Raiding the refrigerator at night is a :"No No"too.
    I suggest:Niacin,Oat Bran and Soy milk.I will be glad to answer questions(If asked)

    April 10, 2010 at 00:12 | Report abuse | Reply
  3. Dr. Reid Winick, DDS

    What a great and timely blog entry. Demand for Sleep Apnea treatments at my dental office, Dentistry for Health New York, has become a growing concern for adults as well as children. Some studies have shown that when a child is grinding their teeth when sleeping, the reason is, is to open their airway to get more oxygen.

    We all know of the increased risk of heart disease when a patient has gum disease. How interesting is it that another dental problem, such as Sleep Apnea, also increases the risk of heart disease and stroke.
    Mild and moderate Sleep Apnea can be treated very successful with a special oral appliance made by a trained dentist. It is so effective, that Medicare has started paying for the home sleep test and the special oral appliance.

    Additionally, we now detect and treat the number one risk factor using a special, simple test in our dental office. It has been researched by the great Mayo Clinic for many years. Information can be seen at http://www.dentistryforhealthny.com/heartdiseasepredictor.html.

    Basically, by testing for endothelial cell dysfunction, the number one risk factor for heart disease and stroke, we can predict a patient’s probability of having a heart attack or stroke 8 to 10 years down the road. Then, if needed, we work with an endothelial medical specialist to improve the dysfunction. In my opinion, this peak into the future is invaluable.

    I hope this post is helpful,

    Reid Winick, DDS

    April 10, 2010 at 21:09 | Report abuse | Reply
  4. Kevin Campbell

    Excellent information. My experience is the same – "Because sleep apnea symptoms happen at night, when the patient is asleep, many don't realize they are affected and can go years, even a lifetime, suffering from the condition and not knowing it." Several of my clients have been diagnosed with sleep apnea and they went years before they seeked treated, thinking they simply slept poorly and their decreased energy was due to something else.


    April 13, 2010 at 22:19 | Report abuse | Reply
  5. Jen

    Do they suspect that the increased stroke risk is related to increased incidence of atrial fibrillation in this patient population? Or does it seem to be a separate entity?

    April 15, 2010 at 22:06 | Report abuse | Reply
  6. Reid Winick

    It is my understanding that with the sleep apnea patient we see a decrease in nitiric oxide (NO). This in turn is linked to decreased endothelial cell function and thus an increased risk of heart disease and stroke.

    Dr. Reid Winick, DDS

    April 16, 2010 at 13:26 | Report abuse | Reply
  7. njannie182

    I believe that there are many more health issues connected to sleep apnea that have yet to be identified. I suffered from debilitating migraines for a few years and tried to find the trigger unsuccessfully. In the meantime, I was diagnosed with sleep apnea. From the day I started on the CPAP, I haven't had a migraine since. My friend's father began to have severe memory loss and it was suspected that it was early dementia – wrong! Yes, it was sleep apnea. Since he began on the CPAP, his mental function is back to 100%.

    Would love to know if there are any serious studies on the effects of this very common condition.

    April 16, 2010 at 13:59 | Report abuse | Reply
  8. Dr. Gordon Chee, DDS

    Hi Njannie182,

    It is a lack of Stage 3/4 sleep that affects memory loss. When you have sleep apnea, you don't get much of that deep sleep you need to transfer information to your "internal harddrive".

    Migraines are commonly caused by bite problems. Does your CPAP machine affect your jaw position? We commonly treat mild to moderate sleep apnea with a dental device that positions the jaw more forward to open up the airway. We also commonly treat migraines associated with TMJ/TMD with a neuromuscular orthotic appliance that also commonly positions the jaw more forward but in a different way. You can find more information on our website here:



    May 19, 2010 at 10:07 | Report abuse | Reply
    • njannie182

      Dr. Chee,

      Thanks for your reply and concern but my migraines ENDED once I began using the CPAP. The migraines were most likely due to low blood oxygen or just plain lack of good quality sleep. I do, however, have a small jaw and am sure that it has been one of the factors in my apnea. Now that I have lost weight and my apnea is fairly mild, I will certainly look at your information regarding an orthotic appliance as it may be something that would benefit me at this juncture.

      The unfortunate thing about apnea is that most doctors don't consider that it could be the trigger for many health issues, such as migraines, memory loss, high blood pressure, weight issues, etc. and many people go undiagnosed.

      July 29, 2010 at 11:58 | Report abuse |
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