March 27, 2012

Heart disease is bad for your sleep

Another heart-disease related story in the Herald (the American College of Cardiology is having its annual meeting now) talks about a link between sleep  and heart disease.  The Herald quotes the principal investigator, Rohit Arora

We now have an indication that sleep can impact heart health, and it should be a priority.

Based on these findings, it seems getting six to eight hours of sleep everyday probably confers the least risk for cardiovascular disease over the long term.

The study actually looked backwards in time, asking people how much sleep they (currently) get per night, and whether they have previously been diagnosed with various heart conditions.  So, it really doesn’t say much about the effect of sleep on heart disease.  Other news sources used a different quote from Dr Arora

“We don’t know whether sleeping longer causes heart complications or whether the heart problems cause someone to sleep longer”

Indeed we don’t.

It’s also a bit strange that the study, based on the large US NHANES survey involved only 3019 people.  NHANES examines more than 10000 people in each two-year wave, and even restricting to people over 45 should leave more than 3000 of them.


Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »