Dementia is devastating to individuals and their families. It robs people of their memory and eventually destroys reasoning, speech, and other functions. Because the risk of dementia increases dramatically with age, health officials have long worried that as people live longer than ever before, cases of Alzheimer’s disease and other kinds of dementia will skyrocket.
However, there’s reason to be hopeful fewer elders will be faced with dementia in the future. Although no cure and no long-term effective treatments have been found so far, the rate of new cases of dementia appears to be decreasing, according to a Boston University study. And if scientists can figure out why, it could reveal ways to stop or delay dementia.
"Effective prevention could diminish in some measure the projected explosion in the number of persons affected with the disease in the next few decades," researcher Sudha Seshadri, MD, professor of neurology at Boston University School of Medicine, said.
Seshadri and her colleagues poured over data on 5,205 people who participated in the Framingham Heart Study (FHS) for decades. The research subjects, who are now 60 or older, were tracked since l975 so investigators could look for signs of dementia over time.
The research team collected extensive information, including the participants’ medical exams and records, test results of those suspected of having neurological problems, and interviews with family members. They also looked at factors that might have a bearing on developing memory problems — including educational status, age, and sex. Existing risk factors for vascular and cardiovascular diseases — such as diabetes, high blood pressure, high cholesterol, and obesity — were tracked, too.
The results of the study showed the incidence of dementia declined significantly over the course of almost 40 years. In fact, there was an average 20 percent reduction in dementia rates each decade since the 1970s, when the FHS information on participants was first collected.
The researchers analyzed their collected data and, while they haven’t pinpointed what factors have contributed to a decline in dementia, they did find some clues. For example, only the study participants with a high school education or higher had a lowered rate of dementia over the decades — and previous research has suggested people with more education are at lower risk for Alzheimer’s and related memory conditions.
In addition, the type of dementia associated with vascular risk factors declined the most. This suggests more effective treatments and prevention strategies for stroke and heart disease put into practice over the last decades may play a role in keeping some people’s brains healthier.
While the findings don’t fully explain the decrease in dementia rates, they give credence to the idea many cases of dementia may be preventable or delayed. The question is — how?
What’s needed, the research team concluded, is more funding for scientists to explore environmental and lifestyle factors that could explain the decrease in dementia cases discovered in the FHS study.
Any way to lower the odds that dementia will strike, or to keep it at bay for as long as possible, could have profound impact on not only those at risk for dementia but also their families and caretakers. Currently, about six million Americans have Alzheimer’s disease, making it the sixth leading cause of death in the U.S., according to the National Institute on Aging.
Worldwide, the World Health Organization estimates that 47.5 million people have dementia and, unless ways are found to prevent or cure the disease, the total number of people with dementia is expected to reach 75.6 million in 2030, and almost triple by 2050 to 135.5 million.
"Currently, there are no effective treatments to prevent or cure dementia; however, our study offers hope that some of the dementia cases might be preventable — or at least delayed — through primary (keep the disease process from starting) or secondary (keep it from progressing to clinically obvious dementia) prevention," said neurologist Seshadri.
May 13, 2016
Christopher Nystuen, MD, MBA