People who suffer from insomnia may be at a three-fold higher risk of developing heart failure, a new study has claimed.
The study was the largest yet to investigate the link and followed 54,279 people between the ages of 20 to 89 for an average of more than 11 years.
"We related heart failure risk to three major insomnia symptoms including trouble falling asleep, problems staying asleep, and not waking up feeling refreshed in the morning," Dr Lars Laugsand from the Norwegian University of Science and Technology, Trondheim, Norway, said.
"In our study, we found that persons suffering from insomnia have increased risk of having heart failure. Those reporting suffering from all three insomnia symptoms simultaneously were at considerably higher risk than those who had no symptoms or only one or two symptoms," Laugsand said.
He stressed that although the study shows that insomnia is linked to an increased risk of heart failure, it does not show that it causes it.
"We do not know whether heart failure is really caused by insomnia, but if it is, insomnia is a potentially treatable condition using strategies such as following simple recommendations concerning sleeping habits (often referred to as sleep hygiene), and several psychological and pharmacological therapies," he said in a statement.
"However, further research is also needed to find the possible mechanisms for this association," he said.
Laugsand and his colleagues collected data from men and women enrolled in the Nord-Trondelag Health study (HUNT) between 1995 and 1997 and who were free from heart failure when they joined.
The researchers followed the study participants until 2008, by which time there had been a total of 1412 cases of heart failure.
When participants joined the study they were asked whether they had difficulty going to sleep and staying asleep, with the possible answers being "never", "occasionally","often" and "almost every night".
They were also asked how often they woke up in the morning not feeling refreshed (non-restorative sleep): "never, few times a year", "one to two times per month", "once a week", "more than once a week".
The researchers found a statistically significant three-fold increased risk of heart failure for people who had all three insomnia symptoms, compared to those with none, after adjusting for most confounding factors apart from depression and anxiety.
When they adjusted their findings to include depression and anxiety, the risk was still significant, with a slightly more than four-fold risk of heart failure.
The study was published in the European Heart Journal.
