Older Women with Sleep-Disordered Breathing at Risk of Cognitive Decline, Dementia
Findings suggest potential role for supplemental oxygen for sleep-disordered breathing in elderly
Aug. 9, 2011 - Older women with sleep-disordered breathing, as indicated by measures of oxygen deficiency (hypoxia), were
more likely to develop cognitive impairment or dementia than women without this disorder, according to a study in the August 10 issue of the
Journal of the American Medical Association (JAMA). This is a common condition among senior citizens, affecting up to 60 percent.
Sleep-disordered breathing is a disorder characterized by recurrent arousals from sleep and intermittent hypoxemia.
A number of adverse health outcomes including hypertension, cardiovascular disease, and diabetes have been associated
with sleep-disordered breathing," according to background information in the article.
Cognitive impairment also has been linked to sleep-disordered breathing in some studies, but the design of most of these
studies has limited the ability to draw conclusions regarding this association.
"Given the high prevalence and significant morbidity associated with both sleep-disordered breathing and cognitive
impairment in older populations, establishing whether a prospective association exists between sleep-disordered breathing and cognition is
important,” the researchers said in explaining why they began the study.
“This is especially important because effective treatments for sleep-disordered breathing exist," they added.
The association between prevalent sleep-disordered breathing as measured with polysomnography (monitoring of
physiological activity during sleep) and subsequent diagnoses of mild cognitive impairment and dementia, was examined by Kristine Yaffe, M.D.,
of the University of California, San Francisco, and colleagues.
The study included 298 women without dementia at the beginning of the study (average age, 82.3 years) who had overnight
polysomnography measured between January 2002 and April 2004 in a substudy of the Study of Osteoporotic Fractures.
Sleep-disordered breathing was defined as an apnea-hypopnea index of 15 or more events per hour of sleep. The
apnea-hypopnea index is the number of complete cessations (apnea) and partial obstructions (hypopnea) of breathing occurring per hour of
Cognitive status (normal, dementia, or mild cognitive impairment) was based on data collected between November 2006 and
Measures of hypoxia, sleep fragmentation, and sleep duration were investigated as underlying mechanisms for any
association between sleep-disordered breathing and cognitive impairment.
Among the 298 women, 35.2 percent met criteria for sleep-disordered breathing.
After an average of 4.7 years of follow-up, 35.9 percent of the women developed mild cognitive impairment or dementia
(mild cognitive impairment: 20.1 percent; dementia: 15.8 percent).
Forty-seven women (44.8 percent) with prevalent sleep-disordered breathing developed mild cognitive impairment or
dementia compared with 31.1 percent of those without sleep-disordered breathing.
Analysis of the data indicated that the presence of sleep-disordered breathing was associated with an increased risk of
subsequent mild cognitive impairment or dementia.
The researchers also found, after adjusting for various demographic risk factors, that two measures of hypoxia (an oxygen
desaturation index of 15 or greater and a high percentage of total sleep time - greater than 7 percent - in apnea or hypopnea) were associated
with higher incidence of mild cognitive impairment or dementia.
"Measures of sleep fragmentation (arousal index and wake after sleep onset) or sleep duration (total sleep time) were not
associated with risk of cognitive impairment."
The authors add that their finding that sleep-disordered breathing was associated with an increased risk of cognitive
impairment seems to be related primarily to measures of hypoxia.
"Given the high prevalence of both sleep-disordered breathing and cognitive impairment among older adults, the
possibility of an association between the 2 conditions, even a modest one, has the potential for a large public health impact.
“Furthermore, the finding that hypoxia, and not sleep fragmentation or duration, seems to be associated with risk of mild
cognitive impairment or dementia provides clues to the mechanisms through which sleep-disordered breathing might promote cognitive impairment.
“The increased risk for cognitive impairment associated with sleep-disordered breathing opens a new avenue for additional
research on the risk for development of mild cognitive impairment or dementia and exploration of preventive strategies that target sleep
quality including sleep-disordered breathing," the researchers write.
They add that to fully evaluate the impact of treatment for sleep-disordered breathing in elderly populations, additional
trials with larger sample sizes, longer treatment periods, and more diverse populations are required.
"Of interest, our findings suggest a potential role for supplemental oxygen therapy for sleep-disordered breathing in
elderly individuals; however, its role requires critical evaluation in intervention studies."
Editorial: More Trials Needed of Sleep-Disordered Breathing
An editorial in the same issue of JAMA supports the conclusion that “large trials with continuous positive air pressure (CPAP)
treatment in elderly participants with sleep-disordered breathing should be performed."
"Moreover, in trials evaluating the effects of pharmacological and nonpharmacological (e.g., cognitive training and
rehabilitation) interventions on cognitive function in patients with mild cognitive impairment or dementia, the possible coexistence of
sleep-disordered breathing should be considered,” wrote Nicola Canessa, Ph.D., of the Center for Cognitive Neuroscience, and Luigi
Ferini-Strambi, M.D., of the Universita Vita-Salute San Raffaele, Milan, Italy.
“Finally, physicians of patients with mild cognitive impairment and sleep-disordered breathing for whom treatment with
CPAP may be indicated should consider these results, and future guidelines to formalize the clinical management of patients with mild
cognitive impairment should consider the implications of this study and related research."
It was specifically emotional abuse - rather than
physical abuse or emotional neglect - that was tied to trouble in
getting a good night’s sleep.
“A negative early attachment continues to exert an
influence on our well being decades later through an accumulation of
stressful interpersonal experiences across our lives,” said Cecilia Y.
M. Poon, MA, the study’s lead author. “The impact of abuse stays in the
system. Emotional trauma may limit a person’s ability to fend for
themselves emotionally and successfully navigate the social world”
The data was taken from the National Survey of
Midlife Development in the United States. In 1995, approximately 3,500
adults responded to questions about their childhood. A decade later,
they were asked follow-up questions about sleep, relationships, and
emotional distress. Poon's study looked at the answers from those age 60
During the second round of interviews, the
participants were asked how often within the previous 30 day they had
● trouble falling asleep,
● woke up during the night and had difficulty going back to sleep,
● woke up too early in the morning and were unable to get back to
● felt unrested during the day no matter how many hours of sleep they
Emotional abuse was assessed by asking participants
how often their mother and father insulted or swore at them, sulked or
refused to talk to them, stomped out of the room, did or said something
to spite them, threatened to hit them, or smashed or knocked something
The same survey found that emotional abuse during
childhood also was associated with poorer relationships in adulthood.
Poon speculated that this lack of support, associated with stress,
likely influences sleep quality.
Older adults need about the same amount of sleep
as younger adults (7 to 9 hours nightly), according to Mayo
Clinic sleep specialist Timothy Morgenthaler, M.D.
study published in the February, 2010, issue of the journal
SLEEP, reported older adults sleep about 20 minutes less than
middle-aged adults, who sleep 23 minutes less than young adults.
“As you get older, however, your sleeping
patterns may change. Older adults tend to sleep more lightly and
awaken more frequently during the night than do younger adults.
This may create a need for or tendency toward daytime napping,”
writes in a
Mayo Clinic Q&A.
“If your sleep is frequently interrupted or cut
short, you're not getting quality sleep — and the quality of
your sleep is just as important as the quantity,” he adds.
Dr. Morgenthaler points out that lack of sleep
can affect your immune system.
“Studies show that people who don't get a good
night's sleep or who don't get enough sleep are more likely to
get sick after being exposed to a virus, such as the common
cold. Lack of sleep can also affect how fast you recover if you
do get sick,” he says.
“During sleep, your immune system releases
proteins called cytokines. These substances increase in the
presence of an infection, inflammation and stress. Increased
cytokines are necessary in fighting infection and regulating
deeper sleep. In addition, other infection-fighting cells are
reduced during periods of sleep deprivation. So, your body needs
sleep to fight infectious diseases.
“How much sleep do you need to bolster your
immune system? The optimal amount of sleep for most adults is
seven to eight hours a night. School-aged children and
adolescents need nine or more hours of sleep a night.
“But be careful; more sleep is not always better.
For adults, sleeping more than nine to 10 hours a night has been
associated with weight gain, heart problems, stroke, sleep
disorders, depression and other health concerns.”