The occurrence of dementia is expected to increase with age, but a February 2016 study showed that the risk of developing the disorder is on the decline.
The New England Journal of Medicine published the 30-year National Institutes of Health-funded Framingham Heart Study in which researchers monitored 5,025 participants for incidence of dementia. From 1977 to 2008, on average, the risk of adults 60 or older developing dementia dropped 20% per decade.
For some people, these findings may be hard to believe because of previous predictions showing an impending increase in dementia cases. According to the Alzheimer’s Association, 5.1 million people age 65 and older were affected by Alzheimer’s disease – which can cause dementia – in 2015. They project this number will increase to 7.1 million people by 2025.
However, the results from the Framingham Heart Study suggest that this may not be the case.
The Study
The Framingham study originated in 1948 and was led by Claudia Satizbal and a few of her colleagues from the Boston University School of Medicine. In the beginning, the study was only measuring the cardiovascular health of the participants living in Framingham, Massachusetts.
Researchers were able to gather a lot of data which ultimately led to a greater understanding of the risk factors for heart disease. After achieving success, Satizbal and her team began measuring the natural history of cognitive decline as well.
In 1977, the researchers gathered a group of adults at least 60 years old and who were free of dementia. The average age of the group was 69, while the oldest participant was 89. As more people reached the age of 60, they were also included in the study. The team split 30 years into four separate time periods and examined those who had developed dementia and who did not.
You Might Also Enjoy: “Concussion” Depicts Struggles of a Pathologist Against NFL
The investigators came up with common criteria in order to consistently judge whether a person had developed dementia over the course of their participation in the study. If they showed signs of developing the disease, they were deemed a case, and if not, they remained a part of the study and were monitored for signs of dementia until they died or dropped out of the study.
An individual’s risk of developing dementia has been known to notably increase once they turn 75, but the investigators in this study did not see this trend play out. Even though they found more people living longer lives, researchers saw a progressive decline when it came to the risk of developing dementia.
The Why Behind the Results
How did this happen? Knowing the answer could help scientists implement certain practices that caused the decline. Many of the diseases that cause dementia cannot be prevented, cured or slowed, according to the Alzheimer’s Association.
Dementia is known as a geriatric syndrome, which is a term that defines a set of signs and symptoms that can be caused by both known and unknown diseases along with aging. Two of the main diseases that can cause dementia are Alzheimer’s disease and vascular disease. To reduce the risk of dementia, one would have to first decrease one or a number of the diseases that cause it.
The one that was reduced in this study was vascular disease, which is likely the main reason for the steady dementia decline. However, there was not a significant decline or increase in the development of dementia from Alzheimer’s disease, which is the leading cause of dementia in people age 65 and older.
There are a number of other factors that could be behind this decline. The participants in this study were all members of a middle-class community, meaning they most likely had access to healthcare. There was also no variation in race; the Framingham community was solely made up of white Americans.
What this study may have shown more than anything else is that the aging process is improving. Not only did this study show that more people are living longer, but that the health of older adults isn’t starting to decline until much later in life. However, not everyone ages the same. Social and economic circumstances are typically a large factor in how our bodies will age as time goes by.
Nevertheless, since aging generally plays a role in the risk of developing dementia, these study results may give us a glimmer of hope that the amount of dementia cases in the United States will decline in the next 40 years.
“Can we, a couple of decades down the road, bend the arc?” said New England Journal of Medicine study leader Sudha Seshadri, professor of neurology at Boston University School of Medicine.
“Stroke used to be the second leading cause of death, and now it is the fifth. Maybe we can do this for dementia, too.”
