People with more years of education tend to develop Alzheimer's
disease later in life than those with less formal schooling, but
once the symptoms begin, better-educated people lose their memory
faster than those with less education, a new study reveals
Tuesday.
The study, published in today's issue of Neurology, involved 488
seniors who were followed for an average of six years using annual
cognitive tests, including 117 who eventually developed Alzheimer's
or another dementia.
The participants from New York City's Bronx borough ranged in
formal education levels of less than three years of elementary
school to people with postgraduate education.
The study found that for each additional year of formal
education, the rapid accelerated memory decline associated with
oncoming dementia was delayed by about two-and-a-half months.
However, once that accelerated decline stopped, the people with
more education saw their rate of cognitive decline accelerate four
percent faster for each additional year of education.
"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
Charles 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
added.
"What we think this represents is that there's some amount of
neuronal reserve or compensational ability . . . such that the
pathology of Alzheimer's disease will develop at whatever rate it
develops and people with more education have more neuronal
capacity... and therefore aren't affected until much later in the
natural history of the disease process."
"However, once that disease process gets to a certain level, the
brain cannot handle it anymore and the decline begins and proceeds
more rapidly because there's more pathology there," he said,
referring to the death of cells and other abnormalities in the
brain caused by the progressive disease.
However, Hall said because the subjects were born at a time when
educational opportunities differed markedly from more modern
schooling, it's hard to know 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."
(Agencies via Xinhua News Agency October 23, 2007)