Insomnia Symptoms Tied to Stroke a Decade Later

Insomnia symptoms were associated with an increased risk for stroke, according to a population-cohort study using data from the Health and Retirement Study (HRS).

People reporting less severe insomnia (HR 1.16, 95% CI 1.02-1.33) and more severe insomnia (HR 1.51, 95% CI 1.29-1.77) saw an increased risk of stroke over an average 9 years of follow-up compared with their non-insomniac peers also participating in the national longitudinal study, reported Wendemi Sawadogo, MD, MPH, of Virginia Commonwealth University, Richmond, and coauthors.

Compared with people without insomnia symptoms, the association between more severe insomnia and stroke risk was stronger among the smaller group of individuals under 50 years of age (HR 3.84, 95% CI 1.50-9.85) than their older counterparts (HR 1.38, 95% CI 1.18-1.62), the prospective study published in Neurology found.

"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," the group wrote. "This striking difference suggests that insomnia symptom management may be an effective strategy for stroke prevention, especially in younger adults."

These results build on previous findings that show somewhat mixed results when determining a link between stroke and sleep disorder symptoms outside obstructive sleep apnea. Nevertheless, recent findings show an association between several sleep issues, such as duration of sleep, and stroke risk. Some studies also show difficulties initiating and maintaining sleep to have a positive association with cardio-cerebral vascular events.

"Given that the risk of these cerebrovascular events seems to be concentrated in younger age groups, emphasis on lifestyle and behavior modifications should be considered in tandem with medical therapy," said Ali El-Solh, MD, MPH, of the University at Buffalo in New York, who was not involved in the study.

"Sleep health is often given less emphasis in overall health assessment, yet it has broad implications on an individual's well-being," he told MedPage Today. "The COVID-19 pandemic has made our sleep habits even more challenging. Unless sleep is considered the fifth vital sign, ahead of pain, the socioeconomic burden of poor sleep is going only to escalate."

Sleep was added to the American Heart Association's "Life's Essential 8" cardiovascular health checklist in 2022.

Sawadogo's group reported that the insomnia symptoms experienced by the patients were maintained over consecutive waves of assessments. Notably, "the HRS cohort is replenished every 6 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 investigators 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."

In addition to encouraging further awareness surrounding insomnia and its associations with stroke, researchers urged patients to seek care for persistent insomnia symptoms.

"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," said Sawadogo in a press release.

The researchers based their report on HRS participants from 2002 to 2020 who were stroke-free at baseline (n=31,126). The patient population was 57% women and the average patient age was 61 years. By race, 63% were non-Hispanic white, 18.9% of the patients were Black, and 13.9% were Hispanic.

Insomnia symptoms were self-reported on the Adapted Brief Insomnia Questionnaire, a validated screening tool with scores ranging from 0 (no insomnia) to 8 (severe insomnia symptoms). People scoring 1-4 and 5-8 were separated into less severe and more severe insomnia groups, respectively.

Sawadogo's group noted that certain conditions appeared to significantly mediate part of the impact of more severe insomnia on stroke risk:

• Diabetes: 9.75% (HR 1.04, 95% CI 1.02-1.15)
• Hypertension: 14.59% (HR 1.06, 95% CI 1.04-1.19)
• Heart disease: 14.89% (HR 1.07, 95% CI 1.05-1.19)
• Depression: 17.78% (HR 1.08, 95% CI 1.06-1.22)

Mediation by these factors on the relationship between less severe insomnia and stroke did not reach statistical significance.

Laura Pérez-Carbonell, MD, of the Sleep Disorders Centre at Guy's and St. Thomas' NHS Foundation Trust in London, nevertheless told MedPage Today that these findings indicate that treatment of insomnia should go hand-in-hand with 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. 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," she commented in an email.

Limitations to the study include self-reported insomnia symptoms and the fact that symptoms were weighted equally in an index. Moreover, the type of stroke, ischemic or hemorrhagic, was not distinguishable in the available data. Both the researchers and Pérez-Carbonell encouraged further research.

"Stroke is a major cause of morbidity and disability. There is an increasing understanding of the importance of sleep health. It is important that further possible associations between those are the objective of future research," said Pérez-Carbonell.

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