Shingles Increases Stroke Risk Later in Life

People ages 18 to 40 who had shingles were more likely to experience a stroke, heart attack, or transient ischemic attack (TIA) later on in life than those who had never had shingles, according to a new study that appeared online in Neurology. “We hypothesize that the link between shingles and stroke or TIA occurring many years after shingles may be due to asymptomatic reactivation from its normally dormant state of virus, resulting in vasculitis (inflammation),” says study author Judith Breuer, MD, of University College London. “[Our] findings make us think that reactivating the virus, either as shingles or asymptomatically, over the years following shingles can cause inflammation of the arteries and stroke, TIA, or MI.” Breuer and colleagues analyzed data from a retrospective cohort of 106,601 herpes zoster cases in the UK compared with a control of 213,202 people who did not have shingles. They examined the risks of stroke, TIA, and MI in both groups, adjusting for vascular risk factors, including body mass index >30 kg/m2, smoking, cholesterol >6.2 mmol/L, hypertension, diabetes, ischemic heart disease, atrial fibrillation, carotid stenosis, and valvular heart disease. They reviewed the records for an average of 6 years after the occurrence of herpes zoster—and as long as 24 years in some cases. Those under age 40 who had shingles in the past were 74% more likely to have a stroke, 2.4 times more likely to experience a TIA, and 50% more likely to have a heart attack. Interestingly, participants over age 40 who had shingles were 15% more likely to have a TIA and 10% more likely to have a heart attack, but had no increased risk of stroke compared to those without shingles. Breuer believes that better screening and treatment for stroke risk factors, including diabetes, high cholesterol, and high blood pressure, may explain why these older patients were at lower risk than younger subjects of stroke, TIA, and heart-related events following shingles. The researchers found these patients were significantly less likely than older patients to be asked about vascular risk factors. “People with shingles are more likely to have other risk factors for stroke, TIA, and MI, including high blood pressure, high cholesterol, and obesity,” Breuer says. “So we suggest that doctors who see someone with shingles should take the opportunity to screen them for these other risk factors and treat them if necessary.” In addition, Breuer says the opposite is also true—people with risk factors for stroke, TIA, and MI are more likely to get shingles. “So it might be an idea, if someone is found to have vascular risk factors such as those listed above, to vaccinate them with the zoster vaccine to prevent shingles, which is a nasty disease in its own right,” she says. The researchers are now looking to see if asymptomatic reactivation of the shingles virus is associated with increased risk of stroke, MI, and TIA, and they’re also looking at host genetics to see if that too plays a part. They say additional studies are needed to investigate whether vaccinating against shingles will also prevent stroke, TIA, and MI. —Colleen Mullarkey Reference Breuer J, Pacou M, Gauthier A, Brown MM. Herpes zoster as a risk factor for stroke and TIA: A retrospective cohort study in the UK. Neurology. 2014;82(1):206-12.