Researchers find link between sleeplessness and heart disease

A study published in yesterday’s issue of the Journal of the American Medical Association reveals that people who are chronically short on sleep are much more likely to develop coronary artery calcifications than others.
A team of researchers at the University of Chicago tracked 495 participants in an ongoing study, the Coronary Artery Risk Development in Young Adults (CARDIA). When they were 15 years into CARDIA, the subjects, who wee all 35 to 47 years old and free of coronary artery disease, filled out sleep questionnaires and kept a log of their hours in bed. At night, they wore motion-sensing devices on their wrists to help determine how much they actually slept.
Five years later, 27 percent of those who were sleeping less than five hours a night had developed coronary artery calcification for the first time, while only 6 percent of those who were sleeping seven hours or more had developed it. Among those who were sleeping between five and seven hours a night, 11 percent had developed coronary artery calcification.
After accounting for potential confounding and mediating variables such as age, sex, race, education, apnea risk, smoking status, blood lipids, blood pressure, body mass index, diabetes, inflammatory markers, alcohol consumption, depression, hostility, self-reported medical conditions), the researchers determined that one hour more of sleep per night was associated with a 33 percent decrease in the odds of calcification, comparable to the heart benefit gained by lowering one’s systolic blood pressure by 17 millimeters of mercury.
These findings are obviously significant, but do not necessarily indicate a causal relationship. It seems likely, in fact, that a third factor, which no doubt falls into the catch-all category of “stress,” is responsible for both decreased sleep and the onset of CAD in some people.
I used to get up early or stay up late to fit in a run, so in those days I was probably canceling my risk factors out. Now, having entered the 35-to-47 age bracket while exercising less and becoming more of an insomniac, I might be a great candidate for coronary-artery calcification. If so, this is not the kind of thing that keeps me up at night.

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  1. #1 by ChuckO on December 24, 2008 - 9:36 am

    As you mentioned, stress is a third factor and, as far as I’m concerned, it’s the gorilla in the room. Virtually everyone I’ve ever known who’s had chronic sleep problems has been highly stressed. It’s amazing to me that the researchers didn’t control for it. I know it might be difficult to determine who was stressed and how much, but some sort of self-reporting assessment would have been better than nothing.

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