People over 50 who catch shingles are at a 50 per cent greater risk of suffering a stroke within the next three months, warns new research.
The study shows that shingles increases the short-term risk of a stroke in older adults by half for 90 days.
Researchers say that more than 95 per cent of the world’s adults are infected with the virus that causes chickenpox, and up to a third of them will develop shingles in their lifetime.
Shingles is a viral disease caused by reactivation of the chickenpox virus, varicella zoster (VSV), which causes a painful skin rash to erupt.
Usually the rash is on one side of the body in a single stripe. It is more common in older adults and those with weak immune systems, but anyone who has had chickenpox can develop shingles.
American researchers assessed the risk of stroke among older people in Olmsted County, Minnesota.
About 5,000 adults over 50 who’d had a confirmed episode of shingles, were matched with a group of age and sex-matched people from the same community who had no history of shingles.
The risks for stroke and myocardial infarction (MI) were assessed separately.
Patients with a previous stroke were excluded from the stroke analyses, and those with a previous MI were excluded from the MI analyses.
The short-term risk of stroke and MI were assessed at three months, six months, one year, and three years after shingles.
Lead investigator Doctor Barbara Yawn, of Olmsted Medical Centre, said: “We found there was a 50 per cent increased risk of stroke for three months after shingles, but we also found that people who had shingles had many more risk factors for stroke than those who had not, suggesting they had worse health overall.
“The bottom line however is that shingles was still associated with an increased risk of stroke for three months afterwards even when we made allowances for these multiple risk and confounding factors.”
The researchers found that the association between shingles and MI at three months was neither strong nor robust across different analytic methods used.
Dr Yawn said: “There did appear to be a small increased risk for MI, but when you take other risk factors into consideration, it disappears.”
She said there was no increased risk of either stroke or MI at any point beyond three months.
The researchers questioned why stroke would be more common after an episode of shingles.
Dr Yawn added: “Recent studies have shown that the zoster virus appears to affect vascular tissues as well as the central nervous system and that it may therefore be a systemic illness.
“Another possible explanation is that stroke is a consequence of the inflammatory response that occurs with an acute zoster episode. This increased risk of stroke may be preventable by vaccinating against the zoster virus.”
by Stephen Beech