“It is possible that people with metabolic syndrome and short sleep have more severe problems related to their anatomic nervous system and metabolism. We need future studies that examine these hypotheses in combination, and in different groups of people with metabolic syndrome,” Fernandez-Mendoza suggested.
Nevertheless, “sleep should be evaluated and taken into consideration when calculating cardiovascular and death risk, especially in those who have already developed those risk factors,” he said.
Behavioral and pharmacological approaches to treat sleep disorders — including sleep apnea, insomnia and short sleep — are available and effective, Fernandez-Mendoza noted.
Dr. Byron Lee, director of the electrophysiology laboratories and clinics at the University of California, San Francisco, said it’s hard to know from this study if lack of sleep increases the risk of early death or is simply a sign of poor health.
“Either way, patients should pay close attention to their sleep,” Lee said. “If they are not sleeping well, a visit to the doctor and possibly a sleep study is in order.”
For the study, Fernandez-Mendoza and his colleagues randomly selected more than 1,300 men and women, average age 49, to spend one night in a sleep laboratory. Of these participants, 39 percent had at least three risk factors for metabolic syndrome.
During an average follow-up of nearly 17 years, 22 percent of the participants died, the researchers reported.
People with metabolic syndrome who didn’t get at least six hours of sleep were about two times more likely to die from heart disease or stroke than people without metabolic syndrome who got less than six hours of sleep, the investigators found.
Among those with metabolic syndrome who slept more than six hours, the risk of dying from heart disease or stroke was increased about 1.5 times, the findings showed.
Moreover, people with metabolic syndrome who slept less than six hours were nearly two times more likely to die from any cause, compared with those without metabolic syndrome, Fernandez-Mendoza said.
The association between sleep and metabolic syndrome was eye-catching because the researchers took sleep apnea, a known risk factor for heart disease, out of the equation.
Dr. Steven Feinsilver, director of sleep medicine at Lenox Hill Hospital in New York City, said that a night in a sleep lab can’t really tell you about how well someone usually sleeps.
Still, he said that “sleep is good for you. Getting more sleep might be good for you, especially if you have these other problems.”
The report by Fernandez-Mendoza and his colleagues was published online May 24 in theJournal of the American Heart Association.