Study links shingles to increased risk of cognitive decline

A new study led by researchers at Brigham and Women’s Hospital (United States) has found that shingles outbreaks are associated with an increased long-term risk of cognitive decline by 20 a hundred According to the researchers, the results of the study support the idea of ​​getting vaccinated against shingles to reduce the risk of getting it. The results are published in ‘Alzheimer’s Research & Therapy’. “Our findings demonstrate the long-term impact of shingles and highlight the importance of public health efforts to prevent and promote the uptake of the shingles vaccine,” said author Sharon Curhan. Given the growing number of Americans at risk for this painful and often disabling disease and the availability of highly effective vaccines, the shingles vaccine could be a a valuable opportunity to reduce the burden of shingles and possibly reduce the burden that comes after,” he said. Shingles, medically known as herpes zoster, is a viral infection that usually causes a painful rash. Shingles is caused by the varicella zoster virus (VZV), the same virus that causes chickenpox. After a person has chickenpox, the virus stays in their body for the rest of their life. Most of the time, the immune system keeps the virus away. Years and even decades later, the virus can reactivate in the form of shingles. Almost all Americans over the age of 50 are infected with VZV and are therefore at risk of contracting shingles. There is growing evidence that herpes viruses, including VZV, may contribute to cognitive decline. Subjective cognitive impairment is an individual’s self-conscious experience of worsening or increased frequency of confusion or memory loss. It is a type of cognitive impairment and one of the first visible symptoms of Alzheimer’s disease and other related dementias. Previous studies on shingles and depression have been controversial. Some research shows that shingles increase the risk of dementia, while others indicate an indirect connection. In recent studies, the shingles vaccine was associated with a reduced risk of dementia. To learn more about the relationship between shingles and cognitive decline, Curhan and his team used data from three large, well-characterized studies of men and women over long periods of time: the Nurses’ Health Study, the Nurses’ Health Study 2′ and the ‘Health Professionals Follow-up Study’ ‘. The study included 149,327 participants who completed health status surveys every two years, including questions about shingles times and cognitive decline. Those who had suffered from shingles were compared to those who had not. Curhan designed the study with first author Tian-Shin Yeh, formerly of the Harvard TH Chan School of Public Health. The researchers found that a history of shingles was significantly and independently associated with an approximately 20 percent increased risk of cognitive impairment in both women and men. This risk was higher among males carrying the APOE4 gene, associated with cognitive decline and depression. That same association did not occur in women. Researchers do not know the mechanisms that link the virus to mental health, but there are several ways it could contribute to cognitive decline. Growing evidence links VZV to a vascular disease, called VZV vasculopathy, in which the virus causes damage to blood vessels in the brain or body. Curhan’s group previously found that shingles was associated with an increased long-term risk of stroke or heart disease. Other mechanisms that could explain how the virus can cause mental impairment are inflammation of the brain, direct damage to nerve and brain cells, and the activation of other herpesviruses. The limitations of this research are that it is an observational study, that the information is based on self-reports, and that it included a large white population with a high level of education. In future studies, researchers hope to learn more about preventing shingles and its complications. “We’re looking to see if we can identify risk factors that can be modified to help reduce people’s risk of developing shingles,” Curhan said. “We also want to study can the shingles vaccine help reduce the risk of adverse health outcomes from shingles, such as cardiovascular disease and cognitive decline,” he said.