People genetically predisposed to insomnia may have an increased risk of heart failure, stroke and coronary artery disease, according to new research.

Insomnia, which affects around 24 per cent of Canadians 18 years old or older, is a sleep disorder in which people have difficulty sleeping.

The study, published in American Heart Association's journal Circulation, also found that a genetic liability to insomnia was associated with an increased risk of large artery stroke – or an interruption of blood flow in one of the main large arteries in the brain.

Swedish and U.K. researchers looked at 1.3 million participants with or without heart disease and stroke from four major public studies and groups to gather their data.

Previous studies have found similar connections between higher risks of heart stroke and insomnia but researchers couldn’t definitely say insomnia was the cause.

Susanna Larsson, the study’s lead author and an associate professor of cardiovascular and nutritional epidemiology at Karolinska Institutet in Stockholm, explained in a press release how the researchers used a novel way to figure out if insomnia was the cause rather than an effect of heart disease.

Her team used a technique called Mendelian randomization, in which they looked at people with gene variants connected to a potential risk factor for insomnia.

This was done to reduce bias in the results and more strongly suggest that the genetic link between insomnia and heart issues was causal rather than just associated.

But Larsson acknowledges that also leads to a study limitation because this means the results represented a genetic variant link to insomnia, rather than insomnia itself. Another limitation was that the majority of the participants were people with European ancestry.

Her team noted it wasn’t clear if improving insomnia would improve cardiovascular health.