I agree with Steffan Lindeberg's statement completely when he says

Grant's study is interesting since there is so little cross-cultural data
on Alzheimer's disease (AD) in relation to diet. If the noted statistical
relation to fat intake (or total energy intake) can be confirmed, I would
be interested to see more research on intake of micronutrients (e.g.
antioxidants) which is negatively related to fat intake (or total energy
intake) in most cross-cultural settings.

And I thank him for putting the discussion group on to Grant's
paper which is thorough and a gold mine of references.  I have long
had a hunch that oxidation was a source of brain degradation and the
death of many runners from brain cancer (anecdotal evidence only at
this stage) may also be related to antioxidant depletion from long
training and free radical stress to brain tissue from oxygen-laden
blood.  To protect my brain, I have taken antioxidants for many
years (though Staffan may argue that it hasn't worked!).

My quarrel is with the lack of diagnostics in the statistics, the
lack of testing of alternative specifications, and with the false
sense of precision which the regression equations and correlation
coefficients convey about the information contained in these crude,
aggregate data (and the way they are used to calculate risks).  I do
not love hypotheses and believe we should attempt to falsify them
and test them against alternatives.

Didn't these sorts of cross-country, epidemiological studies
provide much of the early emphasis for low fat, high carbohydrate
diets?  I don't know the history.

Arthur De Vany
Professor
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http://www.socsci.uci.edu/mbs/personnel/devany/devany.html
University of California
Institute for Mathematical Behavioral Sciences
3151 Social Science Plaza
Irvine, CA  92697-5100