The study is the first in which researchers linked anxiety and stroke independent of other factors such as depression. Anxiety disorders are one of the most prevalent mental health problems. Symptoms include feeling unusually worried, stressed, nervous or tense.

Over a 22-year period, researchers studied a nationally representative group of 6,019 people 25-74 years old in the first National Health and Nutrition Examination Survey (NHANES I).  Participants underwent an interview and took blood tests, medical examinations and completed psychological questionnaires to gauge anxiety and depression levels.

Researchers tracked strokes through hospital or nursing home reports and death certificates. After accounting for other factors, they found that even modest increases in anxiety were associated with greater stroke risk.  People in the highest third of anxiety symptoms had a 33 percent higher stroke risk than those with the lowest levels.

"Everyone has some anxiety now and then. But when it's elevated and/or chronic, it may have an effect on your vasculature years down the road," said Maya Lambiase, Ph.D., study author and cardiovascular behavioral medicine researcher in the Department of Psychiatry at the University of Pittsburgh School of Medicine, in Pittsburgh, Pennsylvania.

People with high anxiety levels are more likely to smoke and be physically inactive, possibly explaining part of the anxiety-stroke link. Higher stress hormone levels, heart rate or blood pressure could also be factors, Lambiase said.

In earlier work, researchers found that depression was linked to greater risk of stroke. In contrast to anxiety, depression is a persistent feeling of hopelessness, dejection, and lack of energy, among other symptoms.

Co-authors are Laura Kubzansky, Ph.D. and Rebecca Thurston, Ph.D.

The National Heart, Lung, and Blood Institute and the National Institute of Mental Health funded the study.