In addition to all the protective factors of high education level and occupation level (since when is a dentist not a scientist?!) and your interest in lifelong learning, that ApoE 2 one of your parents gave you may confer some real benefit.
Here's an excerpt of a meta-analysis of 4 large cohorts published in March 2017:APOE-related risk of mild cognitive impairment and dementia for prevention trials: An analysis of four cohortshttp://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002254#sec019
The Generation Study elected to disclose the following “lifetime” risks of MCI or dementia to its potential participants: 30%–55% for individuals with APOE-e4/e4; 20%–25% for individuals with APOE-e3/e4 and -e2/e4 (with a note that risk might be lower for those with APOE-e2/e4); and 10%–15% for individuals with APOE-e3/e3, -e3/e2, and -e2/e2 (with a note that risk might be lower for those with APOE-e2/e3 and -e2/e2). These values are consistent with our findings, but use round numbers for intelligibility, and broader ranges to reflect statistical and other sources of uncertainty.
I'm guessing that you have lots of time to try out a number of strategies, especially with the pace of clinical insights and research on prevention. And if along the way, you find out how to identify and change the genetics in my family that makes most of us reliable (and grateful) frequent flyers to dentists' offices, that would be great too!