Having shingles may increase the risk of having a stroke later in life, according to research published online in the journal Neurology.
Medical experts at the University College London found that people who contract the viral infection, which produces a painful rash, before the age of 40 are far more likely to have a stroke, heart attack, or transient ischemic attack years later than those who have never had shingles.
Shingles 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, it reactivates years later as shingles.
The new study involved 106,600 people who had shingles and 213,200 people of similar ages who did not have shingles. Researchers reviewed the participants' medical records for up to 24 years and found those under 40 years old were 74 percent more likely to have a stroke if they had had shingles.
The results held true even after accounting for other stroke risk factors such as obesity, smoking, and high cholesterol. People who had shingles in young adulthood were also 50 percent more likely to have a heart attack than those who did not.
Lead researcher Judith Breuer, M.D., said the findings suggest older and younger adults alike who have been treated for shingles should be watched more closely for diabetes, high cholesterol, high blood pressure, and other conditions that rise the risk for stroke and heart problems.
"Anyone with shingles, and especially younger people, should be screened for stroke risk factors," Dr. 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."