Insomnia Linked to Increased Stroke

April 07, 2014

More evidence that insomnia increases the risk for stroke comes from results of a large population-based study.

Researchers reviewed health records from the Taiwanese national population and compared stroke outcomes over a 4-year follow-up in 21,438 patients with a diagnosis of insomnia and 64,314 age- and sex-matched patients without insomnia.

Results showed that overall, insomniac patients had an 85% higher risk of developing stroke. This was reduced to 54% after adjustment for other factors. The effect seemed to be much greater in younger people, with patients with insomnia aged 18 to 34 years having an 8-fold higher risk for stroke than those of a similar age without insomnia.

"Individuals should not simply accept insomnia as a benign, although difficult, condition that carries no major health risks," said coauthor Ya-Wen Hsu, PhD, assistant professor at Chia Nan University of Pharmacy and Science, Taiwan.

"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," he added.

Their findings were published online in Stroke on April 3.

"Reliable" Conclusion

Commenting on the study for Medscape Medical News, Demetrius Lopes, MD, Rush University Medical Center, Chicago, Illinois, said, "I think the conclusion of the study is reliable and likely applies not only to the Taiwanese population."

"The study brings awareness to the increased risk of stroke in young adults with chronic insomnia," he added. "Based on this study we should investigate signs of chronic insomnia in individuals between 18 [and] 34 years old in an effort to reduce stroke. This study is in line with many other publications highlighting the importance of healthy sleeping habits."

The study is the first to try to quantify the risk in a large population group and the first to assess whether the risk for stroke differs by insomnia subtypes, Dr. Hsu said.

During the 4-year follow-up, 583 participants with insomnia and 962 without insomnia were admitted for stroke. Results showed a higher rate of all types of strokes in those with insomnia.

Table 1. Rate of Strokes in Individuals With and Without Insomnia

Endpoint Insomnia (%) No Insomnia (%) Unadjusted Incidence Rate Ratio P Value
Any stroke 7.04 3.80 1.85 <.0001
Ischemic stroke 3.84 2.15 1.79 <.0001
Hemorrhagic stroke 1.12 0.85 1.32 .0268
Unspecified 0.53 0.26 2.07 .0002
Transient ischemic attack 1.55 0.55 2.84 <.0001


Although stroke rates increased with age, as would be expected, the association between insomnia and stroke lessened with age.

Table 2. Association of Insomnia With Stroke: Effect of Age

Age Group (y) Insomnia No Insomnia Incidence Rate Ratio P Value
18 - 34 1.10 0.14 8.06 <.0001
34 - 39 2.56 0.94 2.72 <.0001
50 - 64 7.10 3.81 1.86 <.0001
≥64 18.85 11.02 1.71 <.0001


Researchers divided participants — none of whom had a previous diagnosis of stroke or sleep apnea — into different types of insomnia. In general, insomnia included difficulty initiating or maintaining sleep; chronic or persistent insomnia lasted 1 to 6 months; relapse insomnia was a return of insomnia after having been diagnosed as free of disease for more than 6 months at any assessment point during the 4-year study; and remission was defined as a change from a diagnosis of insomnia to noninsomnia at the subsequent time point.

Participants with persistent insomnia had the highest stroke risk compared with those without insomniacs (hazard ratio [HR], 2.04), followed by those with a relapse of insomnia (HR, 1.76) and those with remission of insomnia (HR, 1.55) in unadjusted analysis. But these HRs became similar among the 3 insomnia subtypes after adjustment for other relevant covariates.

Other factors associated with an increased risk for stroke were older age, diabetes mellitus, hypertension, atrial fibrillation, and lower socioeconomic status.

The mechanism linking insomnia to stroke is not fully understood, but evidence shows that insomnia may alter cardiovascular health via systematic inflammation, impaired glucose tolerance, increased blood pressure, or sympathetic hyperactivity. Some behavioral factors (eg, physical activity, diet, alcohol use, and smoking) and psychological factors (eg, stress) might affect the observed relationship, the researchers suggest.

They conclude that intervention to improve insomnia is needed and studies should evaluate whether such intervention improves cardiovascular health. "To reduce the risk of stroke effectively, health education should be promoted to get individuals to be aware of insomnia symptoms at young age, to treat it, and to track its patterns, especially for younger adults."

The study was supported by the Chi-Mei Medical Center, Tainan, Taiwan. The authors have disclosed no relevant financial relationships.

Stroke. Published online April 3, 2014. Abstract


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