Thoughts from a doctor whose grandparents have dementia.Does the herpes zoster vaccine lower the risk? Research publications continue to emerge.
Kana Yamamoto, M.D., Ph.D Physician, Medical Governance Research Institute
The Japan Meteorological Agency (※1) announced on August 1st that the average temperature in Japan in July was 1.91℃ higher than the same month last year, making it the "hottest July" since records began in 1898. This month too, the intense heat is expected to continue, especially in the first half of the month, with a wide area seeing scorching hot days with maximum temperatures reaching over 35°C. Continuing from July, the government urges people to remain vigilant against "dangerous heat," including paying attention to heatstroke alerts, using air conditioners appropriately indoors, and refraining from unnecessary outings when an alert is issued.
By the way, my grandmother, who suffers from dementia, says that even in this dangerous heat, she doesn't turn on the air conditioner, wears many layers of clothes, and sleeps with a winter blanket over her at night. My friends in Japan have contacted me to say that it's "heat like hell," and I'm extremely worried that my grandmother will get sick or suffer from heatstroke.
Previously, in an article titled “The reality of my grandmother's dementia (※2),” I wrote about my thoughts and feelings after seeing my paternal grandmother suffering from dementia and my parents looking after her. Recently, it was discovered that my maternal grandfather also suffered from mild dementia.
My grandmother and grandfather suffered from dementia, which made me feel a vague sense of anxiety about the distant future, wondering, "Maybe one day when I get older, I'll suffer from dementia too..."
And when I myself suffered from dementia, I even felt scared, because I wouldn't know that I had dementia.
There is still much that remains unknown about dementia, and it remains shrouded in mystery, but research into dementia seems to have progressed steadily in recent years.
■Latest report on dementia prevention
The first latest report I would like to introduce is "Dementia Prevention, Intervention and Care 2024 (※3)," published in the medical journal The Lancet on July 31st, 2024. The findings suggest that around 45% of dementia cases could potentially be prevented or delayed by addressing 14 dementia risk factors at different stages of life, starting from early childhood and continuing throughout life.
So, what are the 14 risk factors that may prevent dementia?
The report lists the 14 following: "low level of education, head trauma, lack of exercise, smoking, excessive alcohol consumption, high blood pressure, obesity, diabetes, deafness, depression, air pollution, few social contacts, high cholesterol, and poor eyesight."
In addition to finding that high cholesterol in middle age (around age 40) was associated with 7% of dementia cases, and untreated vision loss in later life was associated with 2% of cases, the authors say they also found 4 risk factors associated with the greatest proportion of people developing dementia worldwide: "high cholesterol, hearing impairment, less education in early life and social isolation in later life."
However, it is also true that there are issues such as air pollution and early childhood education that cannot be addressed by individuals alone. Therefore, in the report, the authors also recommend 13 policy and lifestyle changes that can help prevent or better manage dementia, based on 14 risk factors.
For example, policy guidelines to government agencies recommend ensuring quality education for all, providing information on the risks of smoking and excessive alcohol consumption and how to prevent them, controlling prices, and preventing smoking in public places.
In terms of lifestyle, the guidelines also recommend, for example, participating in cognitively stimulating activities, using head protection when playing contact sports and cycling, exercising regularly and maintaining a healthy weight, treating obesity as early as possible, keeping systolic blood pressure below 130mmHg from the age of 40, and treating depression, deafness, poor eyesight, and high cholesterol.
Following the results of this survey, American Academy of Neurology fellow Dr. Finney said “Although the full mechanisms of these risk factors need to be further investigated, the results of this survey how a combination of promoting the physical development and health of the brain, preventing damage to the brain, and enhancing and maintaining stimulation of the brain, which in and of itself aids brain health and function”
■Latest Risk Mitigation Report
The second thing I would like to introduce is the latest research report published in Nature Medicine on July 25th, 2024 (※5) which states “ The shingles vaccine ( Generic name: Freeze-dried recombinant shingles vaccine, Product name: SHINGRIX ) may reduce the risk of dementia”
I have previously explained shingles in my articles "Throbbing pain from shingles (※6) - more common in women, pain can last for more than 10 years!?" (※6) and "Increase in shingles due to complications from COVID-19: 'The blisters suddenly become unbearable pain' - what's the reason?" (※7). Shingles is most common in people between the ages of 50 and 70, but it can also occur in younger generations.
According to the latest research report, a comparison was made between approximately 100,000 people aged 65 and over who received ZOSTAVAX (live attenuated shingles vaccine, shingles vaccine approved in the United States in 2006) and approximately 100,000 people aged 65 and over who received SHINGRIX (freeze-dried recombinant shingles vaccine, shingles vaccine approved in the United States in 2017), and the results showed that the probability of being diagnosed with dementia within 6 years of receiving the shingles vaccine was 17% lower in those who received SHINGRIX than in those who received ZOSTAVAX.
In addition, when the study was conducted separately for men and women, it was found that women who received SHINGRIX had a 22% lower risk of developing dementia within the next 6 years compared to women who received ZOSTAVAX, while men who received SHINGRIX had a roughly 13% lower risk.
Furthermore, when comparing older people who received SHINGRIX with those who received the influenza vaccine and a combined diphtheria, pertussis, and tetanus vaccine, it was found that the risk of dementia in older people who received SHINGRIX was 23% lower than those who received the influenza vaccine and 28% lower than those who received the combined vaccine.
At this time, the purpose of getting the shingles vaccine is to prevent shingles. I hope that further research will be conducted and the day will come when we can be sure that the shingles vaccine is effective in reducing the risk of dementia. I would like to start by continuing regular exercise and maintaining a healthy weight.
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This article was originally published in Japanese in AERA dot. on Aug 7, 2024.