 "Education may cut dementia risk: Study")
The risk of developing dementia is decreasing for people with at least a high school education, according to a new study that suggests changes in lifestyle and improvements in physical health can help prevent or delay cognitive decline.
The study, published recently in The New England Journal of Medicine, provides the strongest evidence to date that a more educated population and better cardiovascular health are contributing to a decline in new dementia cases over time, or at least helping more people stave off dementia for longer.
The findings have implications for health policy and research funding, and they suggest that the long-term cost of dementia care may not be as devastatingly expensive as policy makers had predicted, because more people will be able to live independently longer.
There are wild cards that could dampen some of the optimism. The study participants were largely white and suburban, so results may not apply to all races and ethnicities. Still, a recent study showed a similar trend among African-Americans in Indianapolis, finding that new cases of dementia declined from 1992 to 2001. The 2001 participants had more education, and although they had more cardiovascular problems than the 1992 participants, those problems were receiving more medical treatment.
Another question mark is whether obesity and diabetes, which increase dementia risk, will cause a surge in dementia cases when the large number of overweight or diabetic 40- and 50-year-olds become old enough to develop dementia. In any event, in the next few decades, the actual number of dementia patients will increase because baby boomers are aging and living longer.
"You don't want to give the impression that the Alzheimer's or dementia problem is disappearing - it's not at all," said Dallas Anderson, a programme director on dementia at the National Institute on Aging, one of two agencies that financed the study. "The numbers are still going up because of the aging population." Still, he added, the new research shows that "what happens in a person's life becomes important."
"It's not just: Oh, it's in your genes. You're going to get it," he said. "You can take steps to postpone the disease."
The decline reported in the new study was strongest in vascular dementia, which is most directly linked to cardiovascular problems. Alzheimer's, the most common form of dementia, also declined, but the trend narrowly missed what researchers consider statistically significant. Still, Maria Carrillo, chief science officer for the Alzheimer's Association, an advocacy group, said "this tells me there absolutely is hope for Alzheimer's" if a push for healthier lifestyles accompanies efforts to find dementia treatments.
Dementia experts and advocacy groups have long predicted that the number of Americans with dementia, now about five million, would triple by 2050. But a burst of new research in Europe, Canada and the US has pointed to decreases in recent decades in more educated populations with better-controlled cholesterol, blood pressure, and heart and lung health.
"There's more studies suggesting that the risk is going down and we might have to rethink some of the projections of how big a problem dementia will be 30 years from now," said Kenneth Langa, a professor of internal medicine at the University of Michigan. On Saturday, he will present at an international conference preliminary results from another large study, which found that the prevalence of dementia in a more nationally diverse population declined by about 21 per cent from 2000 to 2010.
Results like this suggest, he said, "that even without a big breakthrough in medication or a vaccine that would stop the Alzheimer's process, that we can do things that lower the risk of dementia long-term."
The New England Journal research is considered especially strong because it looked at the emergence of new cases of dementia, or incidence, and is based on data from the Framingham Heart Study, a large collection of detailed health information that began in 1948 with participants from Framingham, Mass., and has continued to follow them and their children and grandchildren.
Researchers evaluated the cognitive status of 5,025 people aged 60 and older in four time periods beginning in 1977 and found a steady decline of about 20 per cent in new dementia cases each decade. They also found that on average, people were older when they were found to have dementia: 80 years old in the 1970s, compared with 85 in the group evaluated 40 years later.
Significantly, the decline in new dementia cases, or incidence, occurred only with people who had at least a high school diploma. High school graduates were also the only ones whose cardiovascular health, except for obesity and diabetes, improved steadily over the same 40 years.
"Whether education is beneficial in itself or whether education is a marker for other things like poverty and unhealthy lifestyle, we didn't parse that out," said Sudha Seshadri, a neurologist at Boston University Medical Center and a senior investigator with the Framingham Heart Study. She said the study did not yield strong evidence that college-educated people had even lower dementia risk, but with small numbers of college graduates in the study's early groups, it was hard to tell.
©2015 The New York Times News Service
