Insomnia is the most commonly-reported sleep disorder and leads to significantly decreased quality of life. Insomnia can also cause psychiatric consequences when untreated. Now, new research indicates that insomnia is also an independent risk factor for death.

New findings from the Wisconsin Sleep Cohort Study, funded by the National Institutes of Health, revealed that chronic insomnia is associated with a more than 2-fold increase in mortality. The risk remained high across all subtypes of insomnia: difficulty falling asleep, repeated nighttime awakenings, waking too early, and difficulty returning to sleep after awakening.

Sleep data was collected from more than 2200 Wisconsin state employees who completed sleep questionnaires over a 19-year period. If the participants reported more than 5 symptoms of insomnia in the month prior to completing the questionnaire on at least 2 separate surveys, they were classified as having chronic insomnia. Overall, 46% of the survey respondents met the criteria for chronic insomnia. Repeated awakening was reported the most often by of the participants (26%), while the remaining symptoms were reported by 15% to 18% of participants. In the 19-year follow-up, 74 study participants died, revealing an 8.6% mortality rate among those with insomnia, and a 2.6% mortality rate among those without chronic insomnia.

Many comorbid conditions and factors can contribute to insomnia, including age, gender, smoking, sleep apnea, alcohol use, asthma, cardiovascular disease, diabetes, chronic obstructive pulmonary disease, and a history of stroke. When the researchers adjusted the analysis for these variables, insomnia was still independently associated with mortality. Each subtype of insomnia revealed a 2.5- to 3.3-fold increased risk of death.

Quantity and quality of sleep is important, but it is unclear why a lack of sleep is so strongly linked to mortality risk. In part, it may be due to the increased accident rate among people with chronic insomnia, or insomnia may decrease the body’s ability to heal from major illness or injury. Several studies have revealed that the ideal amount of sleep for adults is 7 to 8 hours per night. Too little, or too much, and the risk of death increases dramatically.

Sleeplessness research often faces the chicken-or-the-egg dilemma: does chronic insomnia cause other diseases or do other conditions cause insomnia? Since the answer remains unclear, treatment is elusive and patients often suffer from a long term lack of sleep with little relief. The presence of insomnia predicts depression and cardiovascular disease, but low socioeconomic status, female gender, and younger age predicts insomnia. Long term lack of sleep significantly impairs daily function, leading to decreased motivation, irritability, decreased concentration and attention, and fatigue.

Whatever the cause of effect of insomnia, this new research makes its importance clear: insomnia, even with no other risk factors or conditions present, leads to an increased risk of death. People should be aware of their sleep habits and seek treatment for problems related to sleep. Rest well tonight, and live many happy, healthy tomorrows.

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