Findings from a community cohort study suggests that adults 50 years of age and older might have an increased risk for stroke for 90 days following herpes zoster, researchers reported in Mayo Clinic Proceedings (Jan. 2016; 91(1):33-44).
During the investigation occurring from Jan. 1, 1986 to Oct. 1, 2011 researchers assessed the risk of stroke and myocardial infarction (MI) in a U.S. community-based population of adults from Olmsted County in Minnesota.
A total of 4,863 adults 50 years of age and older with and without herpes zoster and 19,433 sex- and age-matched individuals with no history of herpes zoster were included in this study.
The risks for stroke and 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.
50% increased risk of stroke for three months after shingles
“We found there was a 50% 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,” explained the lead investigator, Dr. Barbara P. Yawn, who was quoted in a press release.
“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,” said Dr. Yawn, director of research, Olmsted Medical Center and adjunct professor, Department of Family and Community Health, University of Minnesota.
Investigators found that the association between shingles and MI at three months was neither strong nor robust across different analytic methods used. “There did appear to be a small increased risk for MI, but when you take other risk factors into consideration, it disappears,” noted Dr. Yawn.
There was no increased risk of either stroke or MI at any point beyond three months.
The investigators raise the question of why stroke would be more common after an episode of shingles.
“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,” stated Dr. Yawn.
“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.”