In those at higher genetic risk of developing Alzheimer's Disease, completing more school and going on to a lifetime of mentally challenging work and leisurely pursuits can delay the onset of dementia by close to nine years, says a new study.
Cultivating both early educational attainment and a habit of stimulating leisure activity in mid- and late-life was the best formula for staving off cognitive impairment among carriers of the APOE4 gene, which predisposes one to develop Alzheimer's Disease, researchers found. And those with better education were more likely to continue to cognitively challenge themselves through middle and old age, giving the better educated an edge from the outset.
Those whose educational attainment ranked in the highest 25% of participants -- whether they carried the APOE4 gene or not -- developed signs of dementia five years later than those with educational attainment in the lowest quartile.
But a modest start was hardly a sentence to late-life dementia: Compared to people who completed the most schooling, those who had limited formal education got an extra dose of protection from Alzheimer's when they spent their fifties, sixties and seventies engaged in mentally stimulating activities.
The study, conducted by researchers at the Mayo Clinic in Rochester, Minn., tracked 1,995 older residents of Olmsted County, Minn. for as many as 10 years, testing each when they were recruited as participants and during at least one follow-up visit. None had dementia at the outset, although 277 had mild cognitive impairment and 539 were carriers of the APOE4 gene, which made them more likely to develop Alzheimer's.
The participants, between 70 and 89 years of age upon recruitment, filled out detailed accounts not only of their educational attainment but of the complexity and mental challenge of their jobs and lesiure activities over the course of their lives.
The authors of the study published Monday in JAMA Neurology said their findings suggested that promoting both education among children and young adults and continued learning among older adults would be an effective way to reduce the human toll -- and the national medical bill -- associated with an "impending dementia epidemic."
A report by the Alzheimer's Assn. estimated that, if a treatment could be found that delayed the onset of Alzheimer's Disease by just five years, the result could be a reduction of 43% in the expected number of patients with Alzheimer's Disease by 2050. That treatment, the authors suggest, may be hiding in plain sight: Encouraging young people to complete high school and get at least some college work and promoting ongoing mental activity among the nation's middle-aged and older may be the secret to driving down the rate of Alzheimer's.