ScienceDaily (Mar. 3, 2010)

Having a shingles infection that affects the eyes may increase the risk of stroke, according to new research published in the March 3, 2010, online issue of Neurology®, the medical journal of the American Academy of Neurology.
For the study, researchers identified 658 people diagnosed with ocular shingles and 1974 without the infection. None of these people had a history of stroke at the beginning of the study. Ocular shingles is an infection of the eye and the skin around the eye caused by the same virus that causes chickenpox. About 10 to 20 percent of all people with shingles have ocular shingles.

During the one-year study, stroke developed in 8.1 percent of the people with shingles and 1.7 percent of the people without shingles.

The study found people with shingles were four-and-a-half times more likely to have a stroke compared to people without shingles. The results were the same regardless of age, gender, high blood pressure, diabetes, heart disease and medications.
"Shingles may represent a marker for increased risk of stroke," said Jau-Der Ho, MD, PhD, with Taipei Medical University in Taiwan.

The study also found the people with shingles were more likely to have ischemic stroke, such as a blood clot, and less likely to have hemorrhagic stroke, such as bleeding in the brain, compared to people without shingles.

"As we face an aging population with increased risk factors for stroke, the results of this study reinforce the importance of preventing stroke in older people who develop shingles," said Gustavo A. Ortiz, MD, with the University of Miami Miller School of Medicine in Miami, who wrote an editorial accompanying the study and is a member of the American Academy of Neurology.

Antiviral drugs are used to treat ocular shingles. The researchers found that there was no difference in the risk of stroke between people who received antiviral drugs and those who did not.

Ortiz says further research is needed because the study did not account for stroke risk factors such as cigarette smoking. Also, the results are based on people in Taiwan, and there may be differences in stroke risk compared to other populations.