2019 Alzheimer's Association Facts and Figures Report Is Now Out

The Alzheimer's Association publishes their Facts and Figures Report each March.  This is my go-to source for where we stand in understanding the disease and the development of treatments.  The 2019 edition is now out, and I've read it.  (I skimmed the sections about care-giving, because isn't relevant to my current interest.)  You can download it here.  I always find it fascinating.

The first object of my fascination was the new section on brain changes.  It's the best systematic description I've seen to date regarding how AD unfolds.  The description draws on recent research that found the disease process beginning 22 years before the onset of symptoms, and atrophy beginning 13 years before symptoms appear.  The research used people with the young onset variety of AD, which may or may not be representative of the timing for "sporadic" AD -- the most common type.

The long incubation period points to one of the challenges of finding a therapy to treat the disease, because so much damage has already occurred before interventions are applied.

This year's report also updates information on the risk factors for AD.  It's not that there are new risk factors, but the report provides more detail on the nature of each.  The risk factors are:

• Age -- 65 or older.  3% of people between 65 and 74 and 32% of people 85 and older have Alzheimer's dementia.  They don't address statistics for people like me with MCI.  I think this is due to the difficulty of assigning the cause of MCI to AD.   Age, of course, does not cause AD, but it grants time and a fertile environment for the disease to develop.
• Presence of the ApoE4 gene variant in your genome.  If you have one copy, you have elevated risk of developing AD, and if you have two copies your risk is elevated farther.  Actual probability values vary with factors like ethnicity.
• Family history.  Irrespective of the presence of the ApoE4 variant, a family history of AD suggests a higher risk factor.  This is not necessarily a genetic phenomenon.  Family members likely share lifestyle choices and environmental factors that increase or decrease the risk of developing AD.
• Cardiovascular disease risk factors.  Heart disease can affect the flow of blood to the brain, and the brain consumes 20% of the body's oxygen and nutrients.  Some factors, like a history of smoking and mid-life obesity, appear to affect both the heart and the brain through similar and differing mechanisms.  Just remember, what's good for the heart is good for the brain.  But, unexplained, is an association between a reduction of risk for AD for people over 85 with obesity and hypertension.  Go figure. 
• Diet in the context of cardiovascular disease factors.  The study makes a connection between the elements of the heart-healthy diets (Mediterranean, DASH, MIND) and reduced risk for AD.
• Multi-domain lifestyle factors.  This is where diet, exercise, social connectivity, and the other factors we discuss in Beating the Dementia Monster come into play.  The discussion draws on the Finnish FINGER study that we discussed in a post on December 17.
• Education.  There is a clear correlation between lesser educational attainment and AD.  Some believe that they type of brain activity that occurs during learning somehow builds resistance to the AD disease process.
• Social and cognitive engagement.  Maintaining social and cognitive activity may support brain health and possibly reduce risk of developing AD.  
• Traumatic brain injury.  There is a clear correlation between TBI and AD.  One study found a two-fold increase in the occurrence of AD from mild TBI.  The report did not clarify if this was a single TBI event or repeated events.    

The discussion ended on a positive note, stating that our growing understanding of the long periods of time required to develop symptoms of AD suggests a much larger window for interventions than were previously considered.

I will address more elements of the report in subsequent post(s).