NEW YORK, Jan 10 (Reuters Health) -- Results of a study of African
Americans aged 65 years and older living in Indiana suggests that six or fewer
years of schooling and a childhood spent in a rural area may increase the risk
of developing Alzheimer's disease, US researchers report.
The study authors write that low levels of education alone may not be a
major risk factor for Alzheimer's, but may serve as a marker of other economic
or environmental factors in childhood that affect this risk later in life.
Although low levels of education have been consistently associated with
increased risks of developing Alzheimer's disease or dementia, the increased
risk of low education in this study was apparent only among patients who spent
their early years in rural environments, report Dr. Kathleen S. Hall and
colleagues from Indiana University School of Medicine in Indianapolis. Their
findings are published in the January issue of Neurology.
In contrast, low education and childhood urban residence was not
associated with an increased chance of Alzheimer's. But the study authors warn
that the number of study participants in this group was small, therefore, "it is
possible that education still may be a risk factor in the urban group. If so, it
would be at a smaller magnitude than the risk in the rural group."
Combining low education level and rural upbringing, however, increased the
odds of developing Alzheimer's disease 6.5-fold compared with the combination of
high education and urban childhood, the researchers note. "Possessing just one
risk factor, however, did not seem to increase the risk of Alzheimer's disease,"
they write.
"Our results suggest that lower education and rural residence have an
interactive effect in increasing the risk for subsequent development of
Alzheimer's disease," the authors conclude.
The investigators speculate that low education may have been associated
with greater levels of poverty, malnutrition and deprivation among children
dwelling in rural environments, affecting their physical and psychological
development. "It might be hypothesized that those individuals with low education
and living in rural areas were exposed to more environmental toxins as the
result of more extensive hours of farm labor compared with children spending
more time in classrooms," Hall's team adds. Furthermore, they note,
African-American farmers from that generation often faced barriers to education,
equal employment, and health and social services.
On the other hand, city dwellers who reached higher education levels may
have been "better able to take advantage of economic and cultural activities
involving continuing intellectual stimulation," the researchers propose.
But Hall and colleagues warn against overinterpretation of their findings.
"It is also possible that (our) findings are unique to the special circumstances
of African Americans in the rural south," they caution. "It is uncertain,
therefore, whether our findings also may apply in other populations and account
for such reported discrepancies (in results on the effects of education as a
risk for Alzheimer's disease)."
