Note on Levels of "Normal" vs. Desirable Intracellular Total Folates, in Relation to Alzheimer's

I guess one thing I was thinking, in that last posting, was that an intracellular total folate level in the neurons in the hippocampus, say, could be relatively constant and "normal," across two groups of people between ages 60 and 80 (with one group going on to develop Alzheimer's), and still be interacting with other individual factors (lifestyle or genetic, etc.) in ways that would be contributing to the development of Alzheimer's. Just because two people have identical, marginally-adequate, intracellular total folate concentrations in their hippocampal neurons doesn't mean one person won't be affected more by that state of marginal adequacy. And I'm more talking about the need for more robust interventions, such as in using bioavailable, reduced folates, than about looking for associations (I realize that some of these differences could average out across large groups of people in a study looking at associations).

I realize that one only looks at a single variable, such as serum folate, and looks for an association in a large study. But my point is that there are all of these flawed or false assumptions about the ways in which tissue-specific concentrations of intracellular folates correlate with serum folate, etc., and these false assumptions can lead to erroneous conclusions.