People who struggle with insomnia may be at an increased risk of stroke, even if their insomnia symptoms are moderate, according to a recent study published in the journal Neurology.

Study details

For the study, researchers looked at data of more than 31,000 participants in the Health and Retirement Study (HRS) between 2002 and 2020 who were stroke-free at baseline.

The participants were asked a series of questions on the Adapted Brief Insomnia Questionnaire, a screening tool with scores ranging from zero (no insomnia) to eight (severe insomnia). Those scoring between one and four were separated into a different group from those scoring between five and eight as less severe and more severe insomnia.

The researchers found that people reporting both less severe insomnia and more severe insomnia had an increased risk of stroke over an average nine years of follow-up compared to those who reported no insomnia.

Specifically, those who scored between one and four had a 16% increased risk of stroke while those who scored between five and eight had a 51% increased risk. The association between insomnia and risk of stroke was especially strong among participants under 50 than older participants.

The researchers also noted that participants with diabetes, hypertension, heart disease, or depression were at an even greater increased risk of stroke.

Discussion

In the study, the authors stated that insomnia symptoms experienced by patients were maintained over consecutive waves of the HRS. According to the authors, "the HRS cohort is replenished every six years with younger participants not previously represented."

"This suggests that insomnia symptoms tend to be chronic, or they were not diagnosed and/or managed in this population," the study authors wrote. "Studies have found that those with insomnia usually fail to discuss their sleep problems with their healthcare providers. This underscores the importance of raising awareness around insomnia symptoms."

As for why younger participants saw a stronger association between insomnia symptoms and stroke risk, the authors suggested "this could be due to the higher incidence of stroke at an older age and the shared causal effect with additional risk factors in the elderly. This striking difference suggests that insomnia symptom management may be an effective strategy for stroke prevention, especially in younger adults."

Phyllis Zee, director of the Center for Circadian and Sleep Medicine at Northwestern University's Feinberg School of Medicine, noted that short, fragmented sleep and sleep apnea can make it difficult for the body to regulate metabolism, blood pressure, and inflammation, all of which are risk factors for stroke.

"Poor sleep can impair the natural blood pressure dipping that occurs during night time sleep and contribute to hypertension — an important risk factor for stroke and cardiovascular disease," Zee said.

Laura Pérez-Carbonell, from the Sleep Disorders Centre at Guy's and St. Thomas' NHS Foundation Trust, said the study's findings suggest treatment of insomnia should go hand-in-hand with the treatment of other chronic conditions.

"We are aware that chronic conditions such as these metabolic/cardiovascular diseases or depression may affect sleep, they are known to increase the risk of stroke, and insomnia is commonly reported by patients suffering from these," she said. "There is an intricate relationship between chronic conditions and sleep disturbances, and this should be kept in mind for an appropriate treatment and holistic support of patients."

Wendemi Sawadogo, an epidemiologist and researcher at the Virginia Commonwealth University and lead author on the study, urged any patients experiencing insomnia symptoms to seek care.

"There are many therapies that can help people improve the quality of their sleep, so determining which sleep problems lead to an increased risk of stroke may allow for earlier treatments or behavioral therapies for people who are having trouble sleeping and possibly reducing their risk of stroke later in life," Sawadogo said. (Short, MedPage Today, 6/7; Prater, Fortune, 6/7; LaMotte, CNN, 6/7; The Guardian, 6/8)