TORONTO - It's been known for years that people with higher education levels tend to develop Alzheimer's disease later in life than those with less formal schooling. But a new study suggests that once the symptoms begin, people with more classroom time go cognitively downhill at a faster rate.
In fact, said lead researcher Charles Hall, the study showed that someone with 16 years of formal education would experience a rate of memory decline that is 50 per cent more rapid than someone with just four years of schooling.
"People with more education experience a delay in the actual decline in memory that is characteristic of people who are developing dementia, in particular Alzheimer's disease," said Hall, a biostatistician at the Albert Einstein College of Medicine.
"However, once that decline begins, it proceeds more rapidly and by the time people are actually diagnosed, they're about at the same place" as less-educated people diagnosed earlier, Hall said Monday from New York.
Scientists believe that better-educated people build up a "neuronal reserve or compensational ability." Although the physical characteristics of Alzheimer's likely develop in the brains of both well-educated and less-educated people at a similar rate, those with more education don't begin showing symptoms until later in the progression of the disease because of this neuronal reserve, he said.
To illustrate the point, Hall cited the case of one research participant - a science professor - who died of cancer during the study period.
The man showed some decline on neurological tests but no decline in handling daily activities, and the researchers assumed his slight cognitive impairment resulted from chemotherapy.
"And we were stunned when the neuropathologist reported a significant pathology of Alzheimer's (in the man's autopsied brain)," he said. "It is not something that any of us would have guessed clinically."
The study, published in Tuesday's issue of the journal Neurology, involved 488 seniors who were followed over time, including 117 who developed dementia. All participants, who were born between 1894 and 1908, were physically and mentally healthy when enrolment for the study began in 1980.
Hall said researchers followed participants for an average of six years using annual cognitive tests. Levels of education ranged from less than three years of elementary school to postgraduate degree work.
The study found that for each additional year of formal education, memory decline associated with oncoming dementia was delayed by approximately 2 1/2 months. But once that accelerated deterioration began, more highly educated subjects experienced a cognitive downturn that occurred four per cent faster for each additional year of education.
For example, a university graduate with 16 years' education and diagnosed at age 85 would have begun to experience accelerated memory loss 3.8 years earlier, at age 81. But a person with just four years of schooling, diagnosed at the same age, would have begun to experience a less rapid rate of decline around age 79, 6.3 years before diagnosis, the study shows.
Hall said because the subjects were born at a time when educational opportunities differed markedly from more modern schooling, it's difficult to predict how the findings would apply to subsequent generations.
"Whether that (would) apply to people who were born in the 1920s or the 1950s who had different life experiences is not known," he said. "Although I don't know any reason why it would not hold, I haven't proven it."
Hall said people shouldn't misinterpret the results and believe that having more education has little benefit against the ravages of dementia in the long run.
"I would not say that it's bad to get more education," he said. "It certainly does not cause the disease process (itself) to speed up, and given the opportunity of an extra year or two of symptom-free life, I would definitively take it."
Neuropsychologist Dr. Mary Tierney, director of the Geriatric Research Unit at Sunnybrook Health Sciences Centre in Toronto, called the findings "quite important and valid, absolutely."
"People who are involved in intellectual activity, problem-solving, they're just generally intellectually stimulated," said Tierney, who was not involved in the study. "So those people, when they start developing the . . . neuronal loss that we find in Alzheimer's, they can compensate more . . . they look better and they perform better in the environment."
And it may not be just formal education in one's early years that promotes cognitive health: there is some suggestion that flexing mental muscles even later in life with puzzles, reading, socializing - and even video games - may help stave off the onset of dementia.
For those without a lot of education, Tierney said "possibly now it's time to compensate . . . Attempt to read more, socialize more, again avoiding the negative lifestyle of the couch potato."
"We don't know if it's going to make a big difference if we get involved in all these activities later (in life)," she said. "But we know it can't hurt. So it's probably better to do it."
