Previous observational studies have found an association between insomnia, which affects up to 30% of the general population, and an increased risk of developing heart disease and stroke. These observational studies were unable to determine whether insomnia is a cause, or if it is just associated with them, explained Susanna Larsson, Ph.D., lead study author and associate professor of cardiovascular and nutritional epidemiology at Karolinska Institutet in Stockholm, Sweden.
In this first-of-its-kind study on insomnia, Larsson and a colleague applied Mendelian randomization, a technique that uses genetic variants known to be connected with a potential risk factor, such as insomnia, to reduce bias in the results. The 1.3 million participants with or without heart disease and stroke were drawn from four major public studies and groups.
Researchers found genetic variants for insomnia were associated with significantly higher odds of coronary artery disease, heart failure and ischemic stroke – particularly large artery stroke, but not atrial fibrillation.
“It’s important to identify the underlying reason for insomnia and treat it,” Larsson said. “Sleep is a behavior that can be changed by new habits and stress management.”
A limitation to this study is that the results represent a genetic variant link to insomnia rather than insomnia itself. According to Larsson, it was not possible to determine whether or not the individuals with cardiovascular disease had insomnia.
Larsson’s co-author is Hugh Markus, M.D., FMed.Sci. Author disclosures are on the manuscript.
The Swedish Research Council for Health, Working Life and Welfare (Forte), the Swedish Research Council, a British Heart Foundation program grant, and the National Institute for Health Research funded the study.