A Stanford Medicine study of Welsh older adults suggests that the shingles vaccine may lower the risk of dementia by 20%. The research offers promising evidence for a new preventive approach in dementia care.
A recent study led by Stanford Medicine has uncovered compelling evidence that receiving the shingles vaccine can significantly lower the risk of developing dementia. Analyzing the health records of older adults in Wales, researchers found that those who were vaccinated against shingles were 20% less likely to develop dementia over the following seven years compared to those who were not vaccinated.
The findings, published in the journal Nature, support a burgeoning theory that viruses affecting the nervous system may elevate dementia risk. If further confirmed, this research suggests that a simple preventive intervention could be within reach.
Understanding Shingles and Dementia
Shingles, caused by the reactivation of the varicella-zoster virus (the same virus responsible for chicken pox), leads to a painful rash. This virus remains dormant in nerve cells after an initial chicken pox infection and can reactivate later in life, particularly in those with weakened immune systems.
Dementia, which affects over 55 million people worldwide, has traditionally been linked to the buildup of plaques and tangles in the brain, especially in Alzheimer’s disease cases. Despite extensive research, breakthroughs in dementia prevention have been elusive, driving scientists to investigate other potential causes, including viral infections.
A Unique Public Health Experiment
Senior author Pascal Geldsetzer, MD, PhD, an assistant professor of medicine at Stanford, recognized an unusual opportunity created by the shingles vaccine rollout in Wales. The Welsh vaccine policy beginning September 1, 2013, created an almost random division where specific age groups were eligible for the vaccine, allowing for a natural experiment.
“All these associational studies suffer from the basic problem that people who get vaccinated have different health behaviors than those who don’t,” Geldsetzer said in a news release. “In general, they’re seen as not being solid enough evidence to make any recommendations on.”
By comparing those who just met the age eligibility to those who narrowly missed it, the researchers could minimize health behavior differences between the groups.
“What makes the study so powerful is that it’s essentially like a randomized trial with a control group — those a little bit too old to be eligible for the vaccine — and an intervention group — those just young enough to be eligible,” Geldsetzer added.
Impressive Results
Evaluating the health records of over 280,000 adults aged 71 to 88, the study found that those vaccinated were 37% less likely to develop shingles and 20% less likely to develop dementia. The distinction between vaccinated and unvaccinated groups was stark, with almost identical demographics and health profiles, further strengthening the study’s credibility.
“It was a really striking finding,” added Geldsetzer. “This huge protective signal was there, any which way you looked at the data.”
Impact on Women
Interestingly, the protective effect of the vaccine was more pronounced in women, potentially due to differences in immune response or dementia progression.
Additionally, there is a potential that the newer shingles vaccine, which uses viral proteins, might be even more effective.
Toward Future Research
Geldsetzer hopes these findings will ignite additional research funding. Successful replication of these results in countries like England, Australia, New Zealand and Canada indicate a strong, consistent trend, yet the ultimate aim is to confirm these findings through a large-scale, randomized controlled trial.
“We just keep seeing this strong protective signal for dementia in dataset after dataset,” he added, expressing optimism for future breakthroughs in treatment and prevention.
Source: Stanford Medicine