Are the rates of dementia in the U.S. really falling? And how is education involved?


The numbers for Alzheimer’s disease and dementia are staggering. One in nine adults in the U.S. age 65 and older—more than five million people—has Alzheimer’s. This number is predicted to reach almost 14 million by 2050. The disease is officially the sixth-leading cause of death in the U.S., and is likely underestimated. Caregivers of patients with dementia have contributed roughly 18 billion hours of unpaid assistance a year, at an estimated economic cost of more than $200 billion.

And on.

But is the future for dementia really so bleak? A new study published in the New England Journal of Medicine on Feb. 11 suggests otherwise: the rates of dementia in the U.S. appear to be dropping. Based on data from the longitudinal Framingham Heart Study, which launched in the 1940s and tracked not only its participants but their descendants as well, scientists found the average risk of dementia in people age 60 and older has declined by around 20 percent per decade since 1977.

Notably, this decline was seen only in the well-educated—those with high school diplomas or better.

James Mastrianni, MD, PhD, Director of the Center for Comprehensive Care and Research on Memory Disorders

ScienceLife spoke with James Mastrianni, MD, PhD, Director of the Center for Comprehensive Care and Research on Memory Disorders, who was not involved in the study, about what these findings mean.

ScienceLife: How good is this news?

James Mastrianni: It’s very good news overall.  This new study supports the findings of other epidemiological studies performed in several countries throughout the world. They all show similar declines in the incidence or prevalence of dementia in the last several decades.

SL: Is there a catch?

JM: I think the caveat with these studies is that they include all types of dementia, not just Alzheimer’s. These findings support a significant reduction in apparent vascular-related dementia incidence. But while there was a trend for reduced incidence, it did not reach statistical significance for Alzheimer’s disease.

We know that cardiovascular disease, high blood pressure, elevated cholesterol, strokes, diabetes and other conditions that promote cerebrovascular disease, contribute primarily to the risk of vascular-related dementia, and to a lesser extent, the development of Alzheimer’s disease. The outcomes of the recent NEJM study and other similar studies suggest that reducing these cardiovascular risks by taking anti-hypertensive medicines, cholesterol lowering agents, etc., contributed in a big way to the incidence reduction that they saw.

However, these didn’t fully explain their findings, leading to the speculation that other lifestyle modifications that were not measured by the study could be contributing to the decline in dementia.

SL: What about the connection between higher education and lower dementia?

JM: This was another interesting aspect of this and other similar studies. The decline in dementia incidence was mainly found in better educated people, those with at least a high school diploma. It suggests that these individuals are possibly implementing other lifestyle changes: they might not only be following their doctor’s recommendations better, but they may be exercising more, have greater levels of social interaction, are engaged in more complex occupations, and other behaviors known to protect against dementia. Exercise in particular has strong effects on reducing or delaying the risk of developing dementia in late life. These are all factors that may have contributed to the findings.

SL: What do these findings mean for doctors and patients?

JM: We as physicians can now better inform our patients, and emphasize to them how important it is to follow recommendations to take their medications for high blood pressure and elevated cholesterol, control diabetes, exercise, etc. If we can reduce the risk factors that lead to cerebrovascular disease, patients can benefit from having a reduced overall risk for dementia and much better outcomes in late life.

These promising reports suggest cautious optimism. Because the aging population is expanding and people are living longer because of better overall health, the actual number of patients in the U.S. that will be affected with dementia is still going to climb and lead to a significant health care burden on the country. As such, we need to continue to push ahead with research that is focused on early detection and treatment of dementia.

In the meantime, the take home message that is extraordinarily important for patients to know is that it is possible to reduce your risk for dementia through adherence to your medical regimen, and lifestyle modifications. This is good news.

About Kevin Jiang (147 Articles)
Kevin Jiang is a Science Writer and Media Relations Specialist at the University of Chicago Medicine. He focuses on neuroscience and neurosurgery, orthopedics, psychology, genetics, biology, evolution, biomedical and basic science research.
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