Shingles is linked to a 20 percent higher long-term risk of cognitive decline, one of the first visible symptoms of Alzheimer’s disease and dementia, a new study finds.
- A new study has found that an episode of shingles is associated with about a 20% higher long-term risk of cognitive decline.
- The risk was higher in men carrying the APOE4 gene.
- Researchers will continue their work to understand the mechanisms of this link and see if the shingles vaccine can help reduce the risk of dementia.
Shingles, medically known as herpes zoster, is a viral infection. Caused by a reactivation of the varicella-zoster virus, the disease is characterized by a painful rash. While shingles is usually mild, a team from Harvard-affiliated Brigham and Women’s Hospital has identified a long-term complication.
According to their study published in the journal Alzheimer’s Research & Therapyan episode of shingles is associated with an approximately 20% increased risk of cognitive decline as we age.
Shingles linked to cognitive decline
To study the link between shingles and cognitive decline, the researchers looked at three large studies, totaling 149,327 participants. They completed health surveys every two years for several years. These included questions about shingles episodes and observed cognitive decline.
Analyzing these data, the scientists noticed that a history of shingles was significantly associated with an approximately 20% higher risk of later suffering subjective cognitive decline.
The risk was even greater in men carrying the APOE4 gene, which is linked to cognitive disorders and dementia. However, this same association was not observed in women, according to the work of the American team.
Shingles and dementia: mechanisms to identify
The mechanisms that link the virus to cognitive health have not yet been elucidated. However, the authors note that the disease has several possible ways of contributing to cognitive decline. “There is growing evidence linking the varicella-zoster virus (VZV) to a vascular disease, called VZV vasculitis, in which the virus damages blood vessels in the brain or body.”they explain in a press release. In fact, in previous research, the team had found that shingles was associated with a higher long-term risk of stroke or heart disease.
Other hypotheses include that cognitive decline results from brain inflammation following VZV reactivation, direct damage to nerve and brain cells, or activation of other herpes viruses.
“We are evaluating to see if we can identify risk factors that could be modified to help reduce the risk of developing shingles.”explains corresponding author Sharon Curhan. “We also want to study whether the shingles vaccine can help reduce the risk of adverse health effects related to shingles, such as cardiovascular disease and cognitive decline.”
