Summary Score in Middle Age Predicts Dementia Status Later in Life
A middle-age protective score significantly predicted old age cognitive status.
WASHINGTON — After long-term follow-up, a summary score comprised of middle-age self-reported educational and occupational attainment was comparable to earlier published risk scores of dementia, with the added benefits of being easily acquired and low in cost.
“Our summary score that was based solely on self-report measures was a good predictor of cognitive status in old age after a mean follow-up of 28 years,” study investigator Eero Vuoksimaa, PhD, of the University of Helsinki, Helsinki, Finland, told Psychiatry Advisor. “This summary score is easily acquired and is a very low cost approach compared to in-laboratory assessments, such as brain imaging and cerebrospinal fluid measures.”
Vuoksimaa presented the findings here at the 2015 Alzheimer's Association International Conference.
For the study, Vuoksimaa and colleagues aimed to create a middle-age summary score that is easily acquired via self-report measures, which could be useful both for clinical and research purposes.
“Many earlier summary scores have been developed in samples of individuals older than 65 years and they have usually included in-laboratory measurements, such as brain imaging or measuring of lipid levels,” Vuoksimaa said.
The study included 2,284 twins from the longitudinal, population-based Finnish Twin Cohort study. Researchers collected middle-age (mean, 47 years) educational and occupational attainment — involving a total of five questions — and old age (mean, 74 years) cognitive status, which was determined by telephone interviews that screened for old age cognitive status. Age was also included in the summary score.
After follow-up (mean, 28 years), 9% of patients had dementia.
Data indicated that the middle-age protective score significantly predicted old age cognitive status (area under the curve=0.77; 95% CI: 0.74-0.8). Researchers also reported that the prevalence of dementia in the lowest protective score category was roughly 35% compared with 0% in the highest category.
“When looking at people who had 6 years of education, which was the most common educational level in our Finnish sample of individuals born before 1938, we still observed the association between our summary score and old age dementia status,” Vuoksimaa said. “This indicates that occupational status in middle age is an important predictor of old age cognitive status. In other words, occupational status in middle age predicts old age cognition over and above educational attainment.”
Furthermore, Vuoksimaa and colleagues used a cut off value of <16 (34% of participants) and found that sensitivity was 69% and specificity was 70%, with a positive predictive value of 19% and a negative predictive value of 96%; the predictive power was comparable to earlier published summary risk scores of dementia, according to the researchers.
Vuoksimaa added that, on average, people with lower educational and occupational attainments differ from those with higher educational and occupational attainments in health-related behaviors and risk factors of dementia, such as smoking and cardiovascular disease.
“Based on our results, we cannot be certain of the causality from higher educational/occupational attainment to better old age cognitive functioning,” he said. “An alternative explanation would be that people who had higher cognitive ability in early life were those who achieved higher educational levels and occupational status and also have a lower risk of dementia in old age.”