BOSTON — The risk for death associated with cardiovascular disease (CVD) and cerebrovascular disease (CBV) is significantly increased in adults who get fewer than 6 hours of sleep a night, a new study with objective sleep data indicates.
Short sleep “multiplies the risk of poor outcomes in people with CVD or stroke,” Julio Fernandez-Mendoza, PhD, from the Sleep Research & Treatment Center, Penn State University College of Medicine in Hershey, Pennsylvania, told.
“We need to look beyond sleep apnea when it comes to CVD morbidity and mortality,” Dr Fernandez-Mendoza said. “Most of these patients without sleep apnea but with CVD or stroke may complain of poor sleep or chronic insomnia, and we know now that when such objective short sleep is present their long-term prognosis is much worse.”
He presented his research here at SLEEP 2017: 31st Annual Meeting of the Associated Professional Sleep Societies.
Two-Fold Increased Risk
Short sleep duration has been associated with CVD and CBV disease and mortality, but most studies have relied on self-reported sleep habits. Therefore, the role of sleep in predicting mortality remains unclear.
Dr Fernandez-Mendoza and colleagues assessed objective polysomnographic data from 1741 men and women in the Penn State Adult Cohort, a general population cohort that’s been followed for more than 16 years. CVD was defined by a history of heart disease, including hypertension or diabetes, and CBV by a history of stroke.
Polysomnographic total sleep time was classified as normal (6 hours or more) or short (less than 6 hours) duration. The researchers used Cox proportional hazard models controlling for multiple potential confounders to test the interaction between objective sleep duration, CVD, and CBV on mortality.
“We found that the risk of mortality associated with CVD and stroke was enhanced in those who slept less than 6 hours in the lab; specifically, their risk of mortality was 1.8-fold and 2.4-fold, respectively. In contrast, in individuals who slept more than 6 hours in the lab, the risk of mortality associated with CVD or stroke was not significantly increased,” Dr Fernandez-Mendoza told.
Table. Risk for Death by Sleep Duration
| Endpoint | Short Sleep: Hazard Ratio (95% Confidence Interval) | Normal Sleep: Hazard Ratio (95% Confidence Interval) |
|---|---|---|
| CVD | 1.83 (1.32 – 2.54) | 0.87 (0.59 – 1.29) |
| CBV | 2.39 (1.28 – 4.44) | 1.26 (0.52 – 3.07) |
In a separate study involving the Penn State Adult cohort, published online May 17 in the Journal of the American Heart Association, the researchers found that the risk for death associated with metabolic syndrome is increased in patients with short sleep duration.
The researchers say adults with CVD or stroke who are short sleepers likely have greater central autonomic and metabolic dysfunction. Clinical trials are needed to test whether lengthening sleep improves the long-term prognosis of adults with CVD, stroke, or metabolic syndrome, they add.
Commenting on the study Steven Feinsilver, MD, director of sleep medicine at Lenox Hill Hospital in New York City, noted that “it’s really hard to get accurate information about how much people really sleep because you can’t trust what people tell you.”
Short sleepers typically estimate their sleep very badly, he noted. “We all remember when we are awake. We don’t remember when we are asleep. So any cohort like this, where you have some objective measurement of how much people really sleep, is pretty interesting, and if you want to prove that bad sleep is bad for your heart it’s nice to have some objective data.”
“It would be great if we could tell people to get more sleep and they will be less likely to die of heart disease and stroke — it is quite possible that that is true, but you can’t tell that from this study,” cautioned Dr Feinsilver.
The study had no commercial funding. Dr Fernandez-Mendoza and Dr Feinsilver have disclosed no relevant financial relationships.
SLEEP 2017: 31st Annual Meeting of the Associated Professional Sleep Societies. Poster 1015. Presented June 5, 2017.
