Will Baby Einstein avoid Alzheimer's disease when she gets old?

Is a higher level of early-life cognitive enrichment (ELCE) associated with lower levels of late-life Alzheimer disease and other common dementia-related pathological changes?  This was a question addressed by research published in the journal JAMA Neurology on June 29, 2020.

Their conclusion: "Early life cognitive enrichment was associated with better late-life cognitive health, in part through an association with fewer AD pathological changes."

So what did they do to get to this conclusion?

The research involved a longitudinal study of 813 elderly participants for seven years through to their deaths.  Their cognition was measured throughout the seven years, and their autopsies looked for evidence of neurodegenerative disease -- notably amyloid plaques and tangles.

At the outset of the research, participants completed an extensive questionnaire to establish an index representing an individual's ELCE.  The index was composed of four indicators of ELCE (early-life socioeconomic status, availability of cognitive resources at 12 years of age, frequency of participation in cognitively stimulating activities, and early-life foreign language instruction). These were established by evaluating education levels of the parents and the number of children in the family; availability of cognitive resources, such as a newspaper subscription, encyclopedias, or a globe, at 12 years of age; frequency of participation in cognitively stimulating activities such as reading; and years of foreign-language instruction by 18 years of age.

The researchers attempted to control for "recall bias" which might result from selective memories of the participants' childhoods.  Most were in their 70s at enrollment.

The findings identified a clear correlation between greater ELCE and fewer plaques and tangles in the autopsy as well as better cognitive performance during the preceding seven years.  In fact, an index one unit higher for a participant correlated with Alzheimer's pathology of someone eight years younger.  It also correlated with a 25% slower rate of cognitive decline.

The researchers evaluated the effect of greater ELCE on eight other brain pathologies.  Only Alzheimer's disease was found to be affected.

Some commentators noted that the cohort was more female, white, and highly educated than the general U.S. population. This creates some questions about how the the results should be interpreted, since we know that Alzheimer's disease unfolds differently in diverse populations.  Are there confounding factors that should have been further considered?

I don't know how much providing children with cognitive stimulation makes them smarter, but I do know that it's a lot of fun!