George: Good, bad and unexpected news about brain health
When it comes to brain health, we live in an era defined by good and bad news, and some unexpected revelations.
Bad news: We don’t know what causes Alzheimer’s disease, our most common dementia.
Alzheimer’s has been theorized to be driven by beta-amyloid protein, as first documented by German psychiatrist Alois Alzheimer in 1910. But, up to 40% of aging adults have amyloid in their brains without showing signs of dementia, calling into question the soundness of the so-called “amyloid hypothesis.” A majority of Alzheimer’s cases also show mixed pathologies, not just the presence of beta-amyloid but also, for example, vascular abnormalities. What we once thought of as a singular disease caused by amyloid is better regarded as an age-related syndrome with overlapping causes. This complicates the prospect of a single-drug cure.
Good news: There are established ways of reducing risk.
Even so, we know there is much we can do to make our brains more resilient to these age-related changes. One underdiscussed dynamic is that the brain is intimately intertwined with the health of the heart and blood vessels. Minimizing diabetes, hypertension, obesity, and high cholesterol; exercising; embracing low-sodium, Mediterranean diets; getting good sleep, and avoiding smoking, air pollution, and excess alcohol will all benefit our vascular systems and keep oxygen and nutrients flowing to the brain. Research has also shown that seeking new learning opportunities (i.e., “use it or lose it”), maintaining social bonds, avoiding head injuries, and treating hearing impairment also protect our brains.
Bad news: Drugs have failed and Alzheimer’s may be uncurable.
Given that “Alzheimer’s” is an age-related syndrome comprising a number of different conditions, it is not surprising that—despite billions of dollars spent — the pharmaceutical industry has had a 100% fail-rate in finding a magic-bullet cure. This includes the FDA’s recent controversial approval of aducanumab, an anti-amyloid antibody that is both ineffective and potentially dangerous. Treating Alzheimer’s by focusing only on beta-amyloid is like a football team playing defense by keying exclusively on the opponent’s running back. Is that one player a critical part of the team? Sure, but locking-in on a single factor causes us to miss contributions of other impact players on the field. Ultimately, curing Alzheimer’s may entail curing multiple age-related processes — a daunting task.
Good news: The aducanumab crisis may push the field in new directions.
Experts have called the FDA’s aducanumab approval its worst decision in recent history. Multiple congressional investigations are underway examining the agency’s conduct vis-à-vis the company (Biogen) that produced it. However, this disaster may finally succeed in pushing the field beyond the amyloid hypothesis.
Bad news: Alzheimer’s cases will continue rising.
We live in an aging country with record numbers of older adults, and the number of people who will experience age-related cognitive challenges will inevitably rise. This will demand that we as a society learn to more compassionately care for people living with dementia and their families.
Unexpected news: The risk of developing Alzheimer’s is falling.
Even as dementia cases are rising, the relative risk of developing Alzheimer’s has been steadily declining by 16% per decade since the 1980s in the U.S., Canada, and four Western European countries. As my colleague, neurologist Peter Whitehouse, and I explore in our new book “American Dementia: Brain Health in an Unhealthy Society,” falling dementia risk for today’s elders is due to mid-20th century investments to improve brain health across populations: health care systems that better treated vascular diseases, successful smoking cessation campaigns, initiatives like the GI Bill/Pell Grants that extended higher education to tens of millions of Americans, and successful removal of lead (a neurotoxin and risk-factor for heart disease) from gasoline.
Our wisest approach to brain health involves individual dementia risk reduction, but also — perhaps more importantly —prevention through collective changes that will generationally provide access to education, good nutrition, quality health care, clean water and air, and home- and community-based services and support for every citizen.