Chronic Insomnia Raises Mortality Risk
If you experience chronic insomnia, researchers with the Wisconsin Sleep Cohort Study have found that individuals with this sleep disorder have a threefold greater mortality risk than people without insomnia. The results of the study will be presented on June 7, 2010, in San Antonio, Texas at the 24th annual meeting of the Associated Professional Sleep Societies LLC.
According to the National Center for Sleep Disorders Research at the National Institutes of Health, about 30 to 40 percent of adults report symptoms of insomnia within a given year. From 10 to 15 percent of adults say they have chronic insomnia. Chronic insomnia is defined as an inability to fall asleep and/or remain asleep at least three nights a week for one month or longer.
The Wisconsin Sleep Cohort Study included 2,242 volunteers who completed two to three surveys for years 1989, 1994, and 2000. Investigators conducted a social security search in 2010 and found that 128 of the participants had died during the 19-year follow-up.
The investigators, studying chronic insomnia, made adjustments for age, sex, and medical conditions such as chronic bronchitis, heart attack, stroke, hypertension, depression, and diabetes. They found that compared with people who did not have insomnia, those with chronic sleep problems were two to three times more likely to die from all causes.
The risk of dying was analyzed in four subtypes of insomnia: chronic early-awakening insomnia (threefold risk), chronic sleep-maintenance insomnia in which people have trouble going back to sleep (threefold), chronic sleep-onset insomnia (2.4-fold), and chronic sleep-maintenance insomnia in which people wake up repeatedly during the night (2.3-fold).
Chronic insomnia can be caused by a variety of factors. According to the Sleep Foundation, insomnia is higher among older people and women. Although rates of insomnia increase with age, most often chronic insomnia is associated with a medical condition. Depression is one of the most common causes, while others include arthritis, heart disease, kidney disease, asthma, hyperthyroidism, sleep apnea, restless legs syndrome, and Parkinson’s disease.
Laurel Finn, a biostatistician at the University of Wisconsin-Madison and the study’s lead author, noted that “Insomnia is a burdensome symptom,” and that “identification of insomnia as a mortality risk factor may have clinical implications and raise the priority level for insomnia treatment.”
Finn L et al. SLEEP