Shingles may increase risk of stroke in later life, study finds

Having shingles may increase the risk of having a stroke years later, according to research published in the January 2, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology.

Shingles is a viral infection that causes a painful rash. It is caused by the same virus that causes chickenpox. After people recover from chickenpox, the virus stays dormant in the nerve roots. In some people, the virus reactivates years later as shingles.

People age 18 to 40 who had shingles were more likely to have a stroke, heart attack or transient ischemic attack, also called a TIA or warning for a stroke, years later than people who had not had shingles. People over 40 who had shingles were more likely to have a heart attack or TIA, but not a stroke, than those who had not had shingles.

The study involved 106,600 people who had shingles and 213,200 people of similar ages who did not have shingles. Using a United Kingdom database, researchers reviewed the participants' records for an average of six years after the shingles diagnosis and for as long as 24 years for some participants.

People under 40 years old were 74 percent more likely to have a stroke if they had had shingles, after adjusting for stroke risk factors such as obesity, smoking and high cholesterol. A total of 40 people with shingles had a stroke, or 0.21 percent, compared to 45 of those who had not had shingles, or 0.12 percent. People under 40 were 2.4 times more likely to have a TIA if they had shingles and 50 percent more likely to have a heart attack.

The numbers were not as large in people over 40. They were 15 percent more likely to have a TIA and 10 percent more likely to have a heart attack if they had shingles.

Study author Judith Breuer, MD, of University College London said that for older people better screening and treatment for stroke risk factors, including diabetes, high cholesterol and high blood pressure, may explain why they are at lower risk than younger subjects of stroke, TIA and heart-related events following shingles.

"Anyone with shingles, and especially younger people, should be screened for stroke risk factors," Breuer said. "The shingles vaccine has been shown to reduce the number of cases of shingles by about 50 percent. Studies are needed to determine whether vaccination can also reduce the incidence of stroke and heart attack. However, what is also clear is that factors that increase the risk of stroke also increase the risk of shingles, so we do not know if vaccinating people can reduce the risk of stroke per se. Current recommendations are that anyone 60 years and older should be vaccinated. The role for vaccination in younger individuals with vascular risk factors needs to be determined."