Experiences
at every stage of life contribute to cognitive abilities in old age
"Declining cognitive function in older adults is a major
personal and public health concern," said Bruce Reed professor of
neurology and associate director of the UC Davis Alzheimer's Disease Center.
The study, "Life Experiences and Demographic Influences on
Cognitive Function in Older Adults," is published online in Neuropsychology, a journal of
the American Psychological Association. It is one of the first comprehensive
examinations of the multiple influences of varied demographic factors early in
life and their relationship to cognitive aging.
The research was conducted in a group of over 300 diverse men
and women who spoke either English or Spanish. They were recruited from senior
citizen social, recreational and residential centers, as well as churches and
health-care settings. At the time of recruitment, all study participants were
60 or older, and had no major psychiatric illnesses or life threatening medical
illnesses. Participants were Caucasian, African-American or Hispanic.
The extensive testing included multidisciplinary diagnostic
evaluations through the UC Davis Alzheimer's Disease Center in either English
or Spanish, which permitted comparisons across a diverse cohort of
participants.
Consistent with previous research, the study found that
non-Latino Caucasians scored 20 to 25 percent higher on tests of semantic
memory (general knowledge) and 13 to 15 percent higher on tests of executive
functioning compared to the other ethnic groups.
However, ethnic differences in
executive functioning disappeared and differences in semantic memory were
reduced by 20 to 30 percent when group differences in childhood socioeconomic
status, adult literacy and extent of physical activity during adulthood were
considered.
"This study is unusual in that it examines how many
different life experiences affect cognitive decline in late life," said
Dan Mungas, professor of neurology and associate director of the UC Davis
Alzheimer's Disease Research Center.
"It shows that variables like ethnicity and years of
education that influence cognitive test scores in a single evaluation are not
associated with rate of cognitive decline, but that specific life experiences
like level of reading attainment and intellectually stimulating activities are
predictive of the rate of late-life cognitive decline. This suggests that
intellectual stimulation throughout the life span can reduce cognitive decline
in old age."
Regardless of ethnicity, advanced age and apolipoprotein-E (APOE
genotype) were associated with increased cognitive decline over an average of
four years that participants were followed. APOE is the largest known genetic
risk factor for late-onset Alzheimer's. Less decline was experienced by persons
who reported more engagement in recreational activities in late life and who
maintained their levels of activity engagement from middle age to old age.
Single-word
reading -- the ability to decode a word on sight, which often is considered an
indication of quality of educational experience -- was also associated with
less cognitive decline, a finding that was true for both English and Spanish
readers, irrespective of their race or ethnicity. These findings suggest that
early life experiences affect late-life cognition indirectly, through literacy
and late-life recreational pursuits, the authors said.
"These findings are important," explained Paul
Brewster, lead author of the study, a doctoral student at the University of
Victoria, Canada, and a pre-doctoral psychology intern at the UC San Diego
Department of Psychiatry, "because it challenges earlier research that
suggests associations between race and ethnicity, particularly among Latinos,
and an increased risk of late-life cognitive impairment and dementia.
"Our findings suggest that the influences of demographic
factors on late-life cognition may be reflective of broader socioeconomic
factors, such as educational opportunity and related differences in physical
and mental activity across the life span."
Story
Source:
The above story is based on materials provided
by University of
California - Davis Health System. Note: Materials may be edited for
content and length.
Journal
Reference:
Paul W. H. Brewster, Rebecca J. Melrose, María J. Marquine,
Julene K. Johnson, Anna Napoles, Anna MacKay-Brandt, Sarah Farias, Bruce Reed,
Dan Mungas. Life
Experience and Demographic Influences on Cognitive Function in Older Adults.. Neuropsychology, 2014; DOI: 10.1037/neu0000098
Cite
This Page:
University of California - Davis Health System.
"Experiences at every stage of life contribute to cognitive abilities in
old age." Science Daily,
25 July 2014. <www.sciencedaily.com/releases/2014/07/140725110944.htm>.
