TY - JOUR
T1 - Cohort effects in age-associated cognitive trajectories
AU - Dodge, Hiroko H.
AU - Zhu, Jian
AU - Lee, Ching Wen
AU - Chang, Chung Chou Ho
AU - Ganguli, Mary
N1 - Funding Information:
Funding Funding sources: R01AG023651, R01AG07562, P30AG008017, and R01AG033581 from National Institute on Aging, National Institutes of Health, and U.S. Department of Health and Human Services.
PY - 2014/6
Y1 - 2014/6
N2 - Background. The age-specific prevalence and incidence of dementia and cognitive impairment in the United States have either remained stable or even slightly declined during the 1980s-1990s. A suggested but untested reason for this improvement in cognitive function over time is higher educational attainment among more recent cohorts. Methods. We used data from two large prospective population-based epidemiological dementia studies conducted in two adjacent regions during the period 1987-2012. We examined whether (i) cohort effects could be observed in age-associated trajectories of cognitive functions and (ii) the observed cohort effects could be explained by educational attainment. Trajectories of neuropsychological tests tapping three domains (psychomotor speed, executive function, and language) were compared among cohorts born between 1902 and 1911, 1912 and 1921, 1922 and 1931, and 1932 and 1943. We examined Age × Cohort interactions in mixed-effects models with/without controlling for education effects. Results. Cohort effects in age-associated trajectories were observed in all three domains, with consistent differences between the earliest born cohort and the most recent cohort. Executive functions showed the strongest and persistent differences between the most recent and other three cohorts. Education did not attenuate any of these associations. Conclusions. Cohort effects were observed in all examined cognitive domains and, surprisingly, remained significant after controlling for educational effects. Factors other than education are likely responsible for the cohort effects in cognitive decline.
AB - Background. The age-specific prevalence and incidence of dementia and cognitive impairment in the United States have either remained stable or even slightly declined during the 1980s-1990s. A suggested but untested reason for this improvement in cognitive function over time is higher educational attainment among more recent cohorts. Methods. We used data from two large prospective population-based epidemiological dementia studies conducted in two adjacent regions during the period 1987-2012. We examined whether (i) cohort effects could be observed in age-associated trajectories of cognitive functions and (ii) the observed cohort effects could be explained by educational attainment. Trajectories of neuropsychological tests tapping three domains (psychomotor speed, executive function, and language) were compared among cohorts born between 1902 and 1911, 1912 and 1921, 1922 and 1931, and 1932 and 1943. We examined Age × Cohort interactions in mixed-effects models with/without controlling for education effects. Results. Cohort effects in age-associated trajectories were observed in all three domains, with consistent differences between the earliest born cohort and the most recent cohort. Executive functions showed the strongest and persistent differences between the most recent and other three cohorts. Education did not attenuate any of these associations. Conclusions. Cohort effects were observed in all examined cognitive domains and, surprisingly, remained significant after controlling for educational effects. Factors other than education are likely responsible for the cohort effects in cognitive decline.
KW - Cognitive aging
KW - Cognitive impairment
KW - Dementia
KW - Epidemiology
KW - Socioeconomic status
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U2 - 10.1093/gerona/glt181
DO - 10.1093/gerona/glt181
M3 - Article
C2 - 24270062
AN - SCOPUS:84901030785
SN - 1079-5006
VL - 69
SP - 687
EP - 694
JO - Journals of Gerontology - Series A Biological Sciences and Medical Sciences
JF - Journals of Gerontology - Series A Biological Sciences and Medical Sciences
IS - 6
ER -