December 26, 2013

No magic bullet, but cautious optimism in journey to halt dementia

Last month brought good news for those interested in preventing or delaying dementia—which is predicted to triple between now and the year 2050, affecting 115 billion people worldwide.

First came the November 21 announcement that The Paul G. Allen Family Foundation will fund a $2.7 million study to learn about the long‑term effects of traumatic brain injury. This grant will support researchers from the University of Washington (UW), Group Health Research Institute (GHRI), and the Allen Institute for Brain Science as they analyze data and brains from the Adult Changes in Thought (ACT) study—a project involving thousands of Group Health members over the past 20 years.

On November 27, colleagues and I e-published a perspective in the New England Journal of Medicine describing progress against the global epidemic of dementia. With far more people now living into old age, the number of people with this condition has been exploding. But if you look at the prevalence of dementia among people born between 1900 and 1950, you’ll see that rates are actually declining. Our analysis of the U.S. Health and Retirement Study, for example, found that in 1993, 12.2 percent of people age 70 and older had cognitive impairment compared with just 9.7 percent in 2002. Three more recent European studies have shown similar declines.

What accounts for this good news? The current population of very old people in developed countries had advantages previous generations did not, including:

  • More education. Some experts believe that challenging intellectual activities may create a “brain reserve” that helps people maintain cognitive function despite the changes that come with age. 
  • Better socioeconomic conditions, which allow people to adopt healthier lifestyles.
  • Less vascular risk: Lower smoking rates and better treatments for high blood pressure and high cholesterol have improved vascular health, which reduces risk for dementia.

These changes are great cause for optimism—and they signal a whole new way to think about preventing and delaying dementia. Until recently, most experts believed nothing could prevent it; the best we could do is to temporarily relieve symptoms with drugs. But now we know we can approach dementia like heart disease: Through public health measures aimed at encouraging middle-aged people to lead healthier lives, we may continue to see a significant decline in future rates.

Next week, I’ll share these messages with an international meeting in London of health ministers, innovators, technology pioneers, researchers, and investors. This G8 Summit on Dementia, sponsored by the United Kingdom’s Department of Health, will focus on finding better ways to quell the epidemic. If this were a meeting about polio or even AIDS, we might hope to learn about a “magic bullet” vaccine that could eliminate dementia. But after decades of research into pharmaceutical solutions for various physiological changes in the aging brain, we’ve learned that each new drug has its limits and harms, and no single medication can affect the wide variety of microscopic changes that occur in the brain over time. 

Instead, many will advocate for better ways to help people prevent, or at least stave off, dementia by countering vascular-related conditions such as heart disease, stroke, and diabetes. We must encourage people to:

  • avoid smoking
  • control blood pressure
  • control cholesterol
  • exercise regularly
  • eat a diet rich in fruit, vegetables, and fish
  • avoid excessive alcohol

And because of the links between education, social activity, and brain health, we need to help people:

  • keep their minds challenged and engaged through learning and social activity as they age.

We must also heed clouds on the horizon—that is, the burgeoning epidemic of obesity and diabetes among younger people in our society and the vascular risk these conditions bring. It’s still too early for this population to experience changes in brain function that may come about because of their health risks. But it’s just a matter of time. Unless we turn the tide, these developments could erase all the gains we’ve recently made in reducing the prevalence of dementia. 

So while we may have no magic pill to cure dementia, a many-pronged approach can help us stay well and keep the brain sharp as long as possible. Here at GHRI, scientists on the ACT study—as well as a host of other research projects—will continue working with our collaborators and the Group Health population to find answers to address all these challenges.

Eric B. Larson, MD, MPH
Vice President for Research, Group Health
Executive Director, Group Health Research Institute