12.20.2013
by Salynn Boyles
Contributing Writer, MedPage Today
Anxiety was found to increase stroke risk in a dose-dependent manner independent of depression and cardiovascular risk factors in a new study.
Researchers reported that people with the most anxiety symptoms had a 33% increase in stroke risk compared with those with the fewest symptoms after controlling for cardiovascular risk factors, using nationally-representative data from the first National Health and Nutrition Examination Survey (NHANES I).
After controlling for depression, high anxiety was still associated with a 13% to 20% increase in stroke risk, researcher Maya J. Lambiase, PhD, of the University of Pittsburgh School of Medicine, and colleagues, wrote in the journal Stroke, published online Dec. 19.
The study is among the few to explicitly consider anxiety in relation to incident stroke, and it is the first to show a dose-response link between the two, the researchers noted.
A 2008 study examined generalized anxiety disorder and failed to find an association with stroke risk. A 2000 trial considered the association between anxiety and stroke and found depression, but not anxiety, to be associated with incident stroke. However, the study failed to consider the unique contributions of anxiety to stroke risk, Lambiase and colleagues wrote.
“Our study looked at anxiety along a continuum in the general population and not as a specific disorder,” Lambiase told MedPage Today. “That is one of the main differences between what we did and the previous studies.”
A total of 6,019 adult participants in NHANES I (1971-1975) were followed for 16.29 years, during which time they underwent interviews, took blood tests and had medical and physiological exams.
Anxiety symptoms were measured using the anxious/tense subscale of the General Well-Being Schedule (GWB) test, which was administered by trained interviewers. Depression was evaluated using the GWB depression subscale (GWB-D), and the Center for Epidemiologic Studies of Depression (CESD) scale. CESD scores were considered both as continuous variables and also as a dichotomy according to the cut point for clinical depression (CESD score ≥16 vs.≤16).
Stroke events were identified through hospital/nursing home discharge reports and death certificates.
A total of 419 strokes identified over the follow-up period, and the analysis revealed a dose response relationship between anxiety and stroke, with every one standard deviation (SD) increase in anxiety associated with a 17% increase in stroke risk when adjusting for demographic factors such as age, education, race and BMI.
Among the other findings:
- The association between anxiety and stroke remained significant in models adjusting for cardiovascular and behavioral risk factors.
- Controlling for depression using residualized GWB-D- (HR 1.13, 95% CI 1.06-1.34), continuous CESD- (HR 1.14, 95% CI 1.04-1.27), or dichotomous CESD- (HR 1.13, 95% CI 1.02-1.24) scores did not change results.
- Similar results were seen for anxiety considered in tertiles controlling for age and sex (high versus low anxiety: HR 1.43, 95% CI 1.14-1.80) and when adjusting for other cardiovascular risk factors (high versus low HR 1.33, 95% CI 1.05-1.69) and residualized GWB-D scores (high versus low HR 1.38, 95% CI 1.38, 95% CI 1.03-1.83).
- Controlling for CESD scores did not change the results, and neither interactions between sex and anxiety nor race and anxiety proved to be significant (p’s>0.37).
- The behavioral factors found to have the most influence on anxiety and stroke were smoking and lack of physical activity, but these factors did not fully explain the association.
“Poor health behaviors may be one pathway linking anxiety with stroke risk,” the researchers wrote. “In the present study, behaviors (particularly smoking and physical activity) had the most sizable attenuating effect on the relationship between anxiety and incident stroke. However, since these behaviors did not account fully for the association between anxiety and incident stroke, direct biological effects of anxiety should also be considered.”
Lambiase said the study highlights the importance of continuing to study the impact of anxiety, independent of depression, on stroke risk.
“Stroke is the number four cause of death and a leading cause of disability,” she said. “After adjusting in many ways for depression, anxiety was still associated with stroke in our study. This needs to be explored further.”
From the American Heart Association:
The study was funded by grant from the National Heart, Lung and Blood Institute and the National Institute of Mental Health.
The researchers report no relevant disclosures.
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