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Counting Sleep

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Counting Sleep

Our culture of 24/7 distractions and demands is sapping our sleep. As up to 70 million Americans report chronic sleep problems and fewer adults get sufficient pillow time, scientists are making new connections among dreams, disorders and disease.

For millennia, humanity turned first to poets to understand the mystery called sleep. In the Iliad and the Odyssey, Homer speaks of gods and warriors partaking of the gift of sleep. Shakespeare peppered his plays so frequently with insomnia, somnambulism, nightmares and possibly sleep apnea that at least one critic has argued the playwright himself was an insomniac, according to the Journal of Clinical Sleep Medicine. In Hamlet’s famous soliloquy, the tortured Prince of Denmark connects sleep with death several times—famously proclaiming, “To die: to sleep; / To sleep: perchance to dream.”

The Danish prince’s oratorical anguish anticipated by several centuries connections that scientists today are beginning to unravel. Indeed, a growing body of evidence shows that sleep is as intimately twined with disease and death as Hamlet soliloquized. We may live in a less lyrical age, but science is giving us new insights into sleep’s essential connections to health. Shakespeare today might well be moved to write of how science not poetry “is fetching jewels from the deep.” Biostatisticians, epidemiologists, clinical psychologists and others are probing the mysteries of sleep, uncovering secrets about its connections to cognitive impairment in the elderly and psychological development of the young, and especially its associations with chronic diseases and ultimately its poetic kinsman, death.

An alignment of new technology and scientific approaches comes at a time when large studies reveal disconcerting data on the nature of sleep in America today. The frenetic pace of contemporary life with its 24/7, multimedia-saturated culture is having clear effects in the bedroom. “Chronic sleep loss is an under-recognized public health problem that has a cumulative effect on physical and mental health,” begins a 2008 CDC Morbidity and Mortality Weekly Report article. The article cites unpublished 2007 CDC data from epidemiologic surveys suggesting that average sleep duration has decreased in the U.S. during the past two decades. Significantly more Americans now experience problems sleeping at least a few nights a week than eight years ago: 64 percent in 2009, compared with 51 percent in 2001, reports the National Sleep Foundation. U.S. adults sleep on average 6.9 hours per night, according to a 2005 poll by the Foundation. (The CDC recommends 7 to 9 hours of sleep per night for adults, 8.5 to 9.5 hours for adolescents and up to 18 hours for infants.) Sleep deprivation and sleep disorders like sleep apnea (a breathing-related disorder) have been associated with health problems such as an increased risk of hypertension, diabetes, obesity, depression, heart attack and stroke.

At Johns Hopkins, a multi-disciplinary team including epidemiologist and pulmonary specialist Naresh Punjabi and  Brian Caffo and Ciprian Crainiceanu are making connections between sleep apnea and chronic diseases. Meanwhile, psychologist Adam Spira is investigating the effects of sleep disorders on older adults’ cognition and on their ability to care for themselves. No longer a realm explored solely by poets, sleep—that essential, primal function of the human body—is increasingly recognized as a priority for public health researchers.

As large studies uncover disconcerting data about American sleep, scientists are deploying new technology and approaches that link sleep to overall health.

A Risk of Death

Meet Joe Higgins. He was 51 when he started having trouble getting a decent night’s sleep. The quality of his sleep had gradually declined for several years, but Higgins thought it was due to the medicine he was taking for his severe allergies.

“I came to dread the two o’clock meeting in the afternoon, because it was virtually impossible to keep your eyes open in that setting,” Higgins recalls, six years later. “And then you’re nodding off driving home from work.” After being tested at a Hopkins sleep center, he learned that his breathing during an hour. The condition is known as sleep apnea (also called sleep-disordered breathing). About one in ten women and one in four men have sleep apnea, which is caused by the recurring collapse of the upper airway’s soft tissue. As the upper airway muscles relax, airflow decreases and oxygen levels in the blood fall. This briefly rouses the sleeper as they struggle to breathe.

Punjabi, an associate professor of Medicine with a joint appointment in Epidemiology at the Bloomberg School, prescribed an ongoing course of continuous positive airway pressure (CPAP) therapy. Higgins wears a mask during sleep that allows the CPAP machine to keep his upper airway clear. It quickly improved Higgins’ sleeping. But this individual clinical success is just a precursor to a larger public health story. Punjabi enrolled Higgins in a study that is examining sleep apnea and diabetes risk. In Higgins’ case, his glucose tolerance has shown marked improvement. “That was something that was important to me,” says Higgins, whose parents both had type 2 diabetes.

“More and more, we’re recognizing the health consequences of a variety of sleep disorders,” says Punjabi, MD, PhD.

In August, Punjabi and Caffo, an associate professor in Biostatistics, published findings in PLoS Medicine that link sleep-disordered breathing with an increased risk of “all cause” mortality, particularly for men ages 40 to 70. “That’s a very important finding,” Crainiceanu says, one that was long suspected but never before shown. The findings also suggest that the increased risk of death is specifically associated with coronary artery disease, though more studies will be needed to confirm this. Drawing on data from more than 6,000 participants in the national Sleep Heart Health Study coordinated by Johns Hopkins researchers, the paper marks 15 years of data gathering and analysis. “I think it breaks new ground, especially in scientific terms,” says Crainiceanu, an associate professor in Biostatistics. “These results are based on the largest community cohort study of sleep.”

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  • kay smolin

    palo alto 94303 11/20/2009 09:22:54 PM

    good info, need more specific fix

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