Insomnia is a risk factor for stroke, and adults under age 40 have the highest stroke risk related to sleep deprivation, according to a study from Taiwan.
Young adults with insomnia had an eight-fold higher risk for stroke than their age-matched peers without sleep problems (incidence rate ratio [IRR] 8.06, 95% CI 3.15-20.6, P<0.0001) and persistent insomniacs had a higher cumulative rate of stroke than those who experienced remissions over 3 years of follow up (P=0.024), researcher , of Chi-Mei Medical Center, Taiwan, and colleagues, wrote in the May issue of .
Action Points
- Note that this population-based study suggested an association between insomnia diagnoses and subsequent hospitalization for stroke.
- Be aware that individuals with other comorbidities may be more likely to receive an insomnia diagnosis due to greater contact with the health system.
Having diabetes also slightly increased insomnia-related stroke risk in the study population.
The investigation is among the first to attempt to quantify stroke risk associated with sleep deprivation in a large population, and the first to examine whether different insomnia subtypes have differing impacts on risk, the researchers wrote.
"This study identifies insomnia as an independent risk factor for stroke in young adults, and that is new," said Demetrius Lopes, MD, director of neuroendovascular surgery at Rush University Medical Center in Chicago, who did not participate in the research.
"We consider risk factors like diabetes and high blood pressure in young adults but we definitely overlook sleep, and this is a population that does not really have good sleep habits," he told . "This study is calling attention to the importance of identifying chronic insomnia in this age group."
Much of the research on sleep and stroke has focused on sleep apnea, sleep-disordered breathing and sleep duration, with far less research having been done on insomnia, the researchers noted.
"The few studies examining the associations between insomnia and stroke were limited by focusing on insomnia among patients with stroke," they wrote, adding that without the use of longitudinal study designs, it is not clear if the presence of insomnia seen in these studies is antecedent to the development of stroke.
In an effort to address this research gap, Hsu and colleagues conducted a longitudinal analysis of data from the Taiwan National Health Insurance Research Database to assess the influence of insomnia on the risk of hospitalization for stroke over 4 years of follow-up.
The study included 21,438 insomniacs (mean age 52) and 64,314 matched people without insomnia (mean age 51). Compared with non-insomniacs, insomniacs had a 54% higher risk of developing stroke (adjusted HR 1.54, 95% CI 1.38–1.72).
When the participants were broken down into insomnia subgroups, persistent insomniacs had a higher 3-year cumulative incidence rate of stroke than those in the remission group (P=0.024).
Among the other study findings:
- The insomniacs-to-non-insomniacs incidence rate ratio for stroke was highest among those age 18 to 34 years (IRR 8.06), and declined with age, with 35-to-49-year-olds having a 2.7-fold increase in risk (IRR 2.72, 95% CI 1.96-3.76, P<0.0001) and 50-to-64-year-olds having a 1.8-fold increase in risk (IRR 1.86, 95% CI 1.54-2.26, P<0.0001).
- Having diabetes along with insomnia was associated with a 1.25-fold increase in risk (IRR 1.25, 95% CI 1.01-1.55, P=0.044).
- The distributions of stroke subtypes differed in the insomnia group, with higher IRR in the insomniacs as compared with the non-insomniacs: ischemia (IRR 1.79, 95% CI 1.56-2.06), transient ischemic attack (IRR 2.84, 95% CI 1.03-1.68) and unspecified stroke (IRR 2.07, 95% CI 1.41-3.03).
Study limitations cited by the researchers included the possibility of sampling bias and the possibility that people in the control group may have had undiagnosed and untreated insomnia.
They concluded that people with insomnia have higher incidences and risks for stroke compared to people without insomnia, especially young people.
"More prospective studies with representative populations and longer follow-up are needed to identify the long-term risks of developing stroke by insomnia subtypes," they wrote. "In addition, the pathophysiological pathways connecting insomnia and stroke need to be investigated."
From the American Heart Association:
Disclosures
The research was funded by the Chi-Mei Medical Center, Taiwan.
The researchers disclosed no relevant relationships with industry.
Primary Source
Stroke
Wu MP, et al "Insomnia subtypes and the subsequent risks of stroke: report from a nationally representative cohort" Stroke 2014; DOI: 10.1161/STOKEAHA.113.003675.