A new study found that infection with the virus caused the elderly to have a 20% increased risk of “subjective cognitive decline” – dementia. This was especially true for men who carried the APOE4 gene, which is known to increase the chances of cognitive decline and dementia.
The findings of the study (“Shingles increases risk of subsequent cognitive decline“, with their results are published in Alzheimer’s Research & Therapy) show the long-term effects of shingles (shingles, medically known as “herpes zoster), and highlight the importance of public health efforts to prevent and promote vaccination against the virus, according to study author Dr. Sharon Curhan of the Channing Department of Online Medicine at Brigham and Women’s Hospital in Boston.
Adding next that “Given the growing number of Americans at risk for this painful and often disabling disease and the availability of a very effective vaccine, shingles vaccination could provide a valuable opportunity to reduce the burden of shingles and possibly reduce the burden of subsequent cognitive decline.”
The new study follows a related study published in July
That six-year study found that people who got the so-called newer “recombinant” shingles vaccines lived 17 percent longer without dementia, compared with those who got the older-generation vaccine.
Shingles is caused by the same virus that causes chickenpox in children. The virus then becomes inactive, but can re-emerge and cause symptoms as the immune system’s defenses weaken in old age.
The data on whether or not shingles may increase the risk of dementia was not clear.
The researchers looked at its relationship with subjective cognitive decline, which is defined as “a person’s self-perception of experiencing worsening or more frequent confusion or memory loss.”
Cognitive decline can be a precursor to Alzheimer’s disease or dementia, although this is not always the case.
The new study looked at data on more than 149,000 people who participated in the Nurses’ Health Study, Nurses’ Health Study 2 and Health Professionals Follow-Up Study, which track the health of nurses and other health professionals.
Participants completed questionnaires every two years, which included items about shingles and cognitive decline.
Any history of shingles was associated with 20 percent higher odds of subjective signs of cognitive decline, the researchers said.
Having the APOE4 gene, which is linked to dementia, further increased the risk for men who had shingles, but not for women.
According to the researchers, it can damage blood vessels in the body and/or the brain, thereby impairing the intellect over time.
“We’re trying to identify modifiable risk factors to reduce people’s risk of developing shingles. “We also want to study whether the shingles vaccine can help reduce the risk of health effects due to the virus, such as cardiovascular disease and cognitive decline,” the researchers note.
The study was funded by a well-known pharmaceutical company, which makes a vaccine against herpes zoster.
