Shingles, known by their scientific name as “the worst thing ever,” are caused by the same virus as chickenpox. Once chickenpox symptoms subside, the virus goes dormant, only to manifest itself years later as an intensely painful rash. As it turns out, that’s not even the worst of it. According to research published January 2, may increase your risk of having a stroke years later.

Scientists looked at 106,600 people who had suffered from shingles, and 213,200 who had not. Using a UK database, they reviewed the participants’ records for an average of six years post-diagnosis, and in some cases as long as 24 years.

The results? 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. Those over 40 were only more likely to have a heart attack or TIA, but not a stroke.

People under 40 years old were 74% more likely to have a stroke if they had had shingles, even 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%, compared to 45 of those who had not had shingles, or 0.12%. 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 for those over 40 were nowhere near as significant.

It’s thought that instances were lower in older participants not due to a distinction in the affects of the virus, but because they receive better screening for stroke risk factors.

“Anyone with shingles, and especially younger people, should be screened for stroke risk factors,” said Judith Breuer, MD, of University College London. “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.”

Maybe hold off on intentionally exposing your children to chickenpox, for now.