But as long as those older adults are getting the shingle vaccine, their odds of getting dementia should reduce as well.
[1] - Intermittent infection with chickenpox boosts the adaptive immune response to the chronic chickenpox infection that most people who ever caught the disease have. This intermittent boosting helps prevent flareups of the chronic chickenpox infection (also known as shingles), which is likely the causative factor in chickenpox-related dementia. Alternatively, instead of getting intermittently infected with chickenpox, they could just get a shingles vaccine instead to boost their immune response against their previously acquired chronic infection.
I presume that this intermittent exposure to chickenpox is greatest in adults with children (and grandchildren). Possibly explaining the decrease in dementia for older people with adult children: https://www.sciencedirect.com/science/article/pii/S235282732...
> Having 3+ children, adult daughter(s), or biological children was associated with lower risk of cognitive impairment.