Dementia rate fell 44% since late 1970s in U.S. town

The new report, using data from the long-running FraminghamHeart Study, shows that dementia rates have decreased by 44per cent since the late 1970s and early 1980s, with nearly all ofthat drop among high school graduates.

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"There was a trend there" for Alzheimer's, said DeanHartley, director of science initiatives with the Alzheimer'sAssociation. It shows "there may be modifiable lifestyles thatmay lower your risk for Alzheimer's."

So many people are entering the age when dementia becomes athreat and life expectancy is increasing so rapidly, the declinein rates of dementia will not translate to an overall drop inthe number of dementia cases, cautioned senior author Dr. SudhaSeshadri, a professor of neurology at the Boston UniversitySchool of Medicine.

The Framingham study is based in a predominately-whiteMassachusetts town west of Boston where thousands of residentshave been closely followed by doctors since 1948. The newanalysis, reported in the New England Journal of Medicine,looked at dementia rates in four 5-year blocks and used datafrom 5,205 individuals.

Those declines translate to reductions of 22 per cent, 38per cent and 44 per cent in the second, third and fourth period,respectively, compared to the rate in the early years.

More education and brain power?

The researchers said some of the drop may be due to declinesin rates of stroke, heart failure and atrial fibrillation, aswell as better treatments for those conditions, "but none ofthese trends completely explain the decrease in the incidence ofdementia."

Dr. Paul Schulz, a dementia neurologist at the University ofTexas Health Science Center in Houston, who was not connected tothe research, pointed out that "there's a lot of healthcareaccess issues related to education (and graduates) may havebetter insurance to see their doctor more often," which mighthave affected the results.

Dementia also tended to show up later in life as time wenton, the study found. The average age of diagnosis was 80 duringthe late 1970s and 85 in the most recent group.

"Rising educational levels might have contributed to the5-year delay we observed in the mean age at onset of clinicaldementia," the researchers said.

Hartley said it's important to fund more research to seewhat lifestyle changes might lower the risk further. "A numberof things people to do to stay healthy" such as exercise, abetter diet and social stimulation "could protect their brain,"he said