According to the American Academy of Sleep Medicine, around 30% of the US population has insomnia. Now, as if having difficulty getting to sleep is not enough, new research suggests that insomniacs are at much higher risk of stroke than those without the sleep disorder.
The research team, including Ya-Wen Hsu of the Chia Nan University of Pharmacy and Science and the Department of Medical Research at Chi-Mei Medical Center, both in Taiwan, recently published their study in Stroke - a journal of the American Heart Association.
To reach their findings, the investigators analyzed randomly selected medical records of more than 21,000 people with insomnia in Taiwan, alongside the health records of 64,000 individuals without the disorder. All participants were followed-up for 4 years.
At the end of the follow-up period, individuals with insomnia were divided into different groups:
- Chronic or persistent insomnia (lasting 1 to 6 months)
- Relapse insomnia (return of insomnia after being free of the condition for more than 6 months at any evaluation point in the study), and
- Remission insomnia (a change from a diagnosis of insomnia to non-insomnia at any point during the study period).
Stroke risk highest among younger insomniacs
Researchers found that insomniacs, particularly those aged between 18 and 35 years at diagnosis, have a much higher stroke risk than those without the sleep disorder.
The researchers found that, throughout the follow-up period, 583 people with insomnia were admitted to the hospital as a result of stroke, while 962 individuals without insomnia were admitted for stroke.
Relative to the number of study participants, the researchers found that individuals with insomnia had a 54% increased risk of hospitalization for stroke, compared with non-insomniacs. Insomniacs who were diagnosed with the disorder between 18 and 35 years old were eight times more likely to be hospitalized for stroke than those without insomnia.
A higher 3-year cumulative incidence of stroke was found in people with persistent insomnia, compared with those in the remission group.
The investigators also found that insomniacs with diabetes had a higher risk of stroke than those without diabetes.
Commenting on the findings, Hsu says:
"We feel strongly that individuals with chronic insomnia, particularly younger persons, see their physician to have stroke risk factors assessed and, when indicated, treated appropriately.
Our findings also highlight the clinical importance of screening for insomnia at younger ages. Treating insomnia is also very important, whether by medication or cognitive therapy."
Although the research team says it is not fully clear as to why insomnia may increase stroke risk, past research has suggested that the sleep disorder can interfere with cardiovascular health by causing inflammation, increasing blood pressure and impairing glucose levels.
They add that certain behaviors - such as diet, exercise, alcohol use and smoking - could also influence the association between insomnia and stroke risk, as well as stress.
'Insomnia should be treated earlier to prevent future disease risk'
Since this study was conducted using participants from Taiwan, it is unclear as to whether the findings apply to other populations. However, the researchers note that studies from other countries have reported a similar link between insomnia and stroke.
"Though insomnia is the most common sleep complaint, it should not be perceived merely as a symptom of another disease," Hsu told Medical News Today. "Rather, it should be identified and treated earlier in clinical settings to prevent future disease risk."
However, he told us that although insomnia is a common problem, the results should not cause public panic regarding future stroke risk.
"Rather, we would like to point out that the patients or general population should pay more attention to their insomnia patterns overtime," he added. "If persistence of insomnia is found, they should seek early treatment to reduce their future risks of stroke."
Other studies have also suggested a link between insomnia and cardiovascular health. Medical News Today recently reported on a study suggesting that daylight savings in spring - when we lose an hour of sleep - may increase the risk of cardiac events, while another study indicates that symptoms of insomnia are associated with higher risk of death from heart-related problems.