Two new studies, one in British and another in Denmark, indicate
that dementia rate in old ages drops sharply. A very good news, indeed.

"And experts on aging say the study confirmed something they long suspected but lacked good evidence to prove; That dementia rate would fall and mental acuity will improve as the populaton grew healthier and better educated. The studies' findings may also give new impetus to efforts to get people to quit smoking and take other steps to lower their risks of heart disease and and stroke." - From NYtimes, by Gina Kolata, July 16, 2013.

Dementia, including Alzheimer's, is preventable, I believe.
As I wrote many times, our brain is plastic, not fixed, can be
changed better or worse, dedending what we do to it. Since it has it's own stem cells in the brain - in olfactory bulbs and hippocampus - we can stimulate them with healthy inputs like
exercises, good diet, and lifetime education to prevent or even
overcome Alzheimer's in a case of a nun, and stroke in a case of a professor.

We all know bad habits to get rid of; over-moderate drinking, smoking, bad food addictiion, overeating, stress,....

Good luck to all of you with better choices for the rest of your
life.