People are living longer now than ever before, but with this triumph comes a truly unfortunate foe – Alzheimer's disease. Symptoms of the progressive brain disorder, which is the most common cause of dementia for older adults, typically start to show up around age 65, just when many people retire and plan to start enjoying their golden years.
This incurable disease is listed as the sixth leading cause of death for older people in the U.S., but the NIH says more recent estimates indicate it should rank third, behind only cancer and heart disease. (Many cases are not reported correctly.) Worse, Alzheimer's is the only disease in the top 10 causes of death in the U.S. for which there is no cure, no means of prevention and no treatment to slow down the disease.
David Lusk, founder of an issue advocacy consulting company Key Advocacy in Arlington, Virginia, knows all too well the tragedy of this disease, having watched his mother's decline. She began exhibiting symptoms like short-term memory loss, struggling with basic paperwork and making decisions with difficulty at age 65, but was not diagnosed until age 70 in 2008.
"By early 2012, my mother no longer believed I was her son," he emails. "It was crushing to have my own mother think she wasn't my mother and she stopped saying 'I love you.' That is the most painful thing to ever endure — never hearing your own mother saying she loves you ever again."
Lusk's mother died in 2013, after following a pattern of cognitive and emotional decline that has become sadly familiar for people dealing with Alzheimer's. He wonders if he will get the disease himself someday, as it tends to run in families. "That 'back of your mind' concern, I try to ignore it, but there is also a part of me that wonders if I'm not already walking down the dark, fatal path so many millions have and will," he says.
As the numbers of people with Alzheimer's skyrockets, it's troublesome that a cure or effective treatment hasn't been found after so many years of research. It's not for lack of effort. In fact, more than 100 drugs have been studied in clinical trials since 2002 to the tune of billions of dollars in funding, but none of these have proved effective enough for patient use.
So, what gives? Why is it so hard to find a treatment for Alzheimer's?
"Some of the difficulty has been in being able to identify really what the initiation of the disease is in people," explains Rebecca Edelmayer, Ph.D., director of scientific engagement for the Alzheimer's Association. "We've learned that some of the changes are occurring maybe 10 to 20 years before they're experiencing the cognitive difficulty. That's the crux. We need to understand what's happening in the brain before you're experiencing symptoms. We're really trying to understand the biology underpinnings of the disease. This is where researchers are most focused at the moment."
Part of the problem is figuring out which people to study 10 years before they're showing any signs of dementia. "We're trying to ID people we believe to be at risk," says Edelmayer. "Maybe [the candidates] have a primary relative that had full-blown Alzheimer's; maybe they have risk factors, poor cardiovascular health or difficulties with their sleep. All of these things put you at risk for being someone to develop Alzheimer's."
Of course, not everyone with poor heart health gets Alzheimer's. Edelmayer notes that one of the ways to try and ID who might be at risk is through biomarkers, which are measurable substances that show up in a living thing when a particular event is occurring. Checking people who aren't yet symptomatic over a period of years and comparing them against people with Alzheimer's in varying stages can shine light on which biomarkers to look out for. Some potential biomarkers which could eventually help to pinpoint those at risk of Alzheimer's include blood and urine tests, genetic profiles, brain imaging and proteins in cerebral spinal fluid.
New evidence from one of the largest clinical trials of its kind revealed in July 2018 that people who aggressively lower their systolic blood pressure to below 120 may reduce risk of cognitive impairment.
"We can modify some of our risk factors by very significantly controlling cardiovascular health," Edelmayer says. "What's good for your heart is going to be good for your brain." Other modifiable risk factors could be related to diet, exercise, drugs that harm the brain and even sleep quality, but those require more study before a definitive recommendation can be made, she explains.
In the meantime, continuing efforts are underway to find a treatment. Certain hallmarks of Alzheimer's, like amyloid plaques and tau tangles are particularly problematic. Edelmayer says that it's crucial to figure out how to "remove those built-up proteins in the brain that we believe are inhibiting neuronal communication in the brain."
An additional area of study focuses on better managing the behavioral symptoms of Alzheimer's that can be so disruptive in day to day life, like sleep problems, agitation or even bouts of aggression. "That will increase the quality of life of people living with Alzheimer's," Dr. Edelmayer says.
To improve detection, the Alzheimer's Association is planning to release 20 recommendations to help doctors make timely diagnoses and establish best-practice protocols for how Alzheimer's should be handled. These guidelines are expected to be published late in 2018.
Lusk is one man among millions who appreciate the efforts scientists are making to try and find a treatment or cure for this disease. If one was discovered, he says he'd feel "amazingly relieved" to not have to dread a diagnosis of Alzheimer's. "To no longer have to worry about that and have that concern? That would be a huge weight lifted off my shoulders."