It wasn't quite a repeat of the Revolutionary War, but older Americans bested their British counterparts in a memory and awareness test.
The authors of the research, published in the open access journal BMC Geriatrics, cited differences in relative levels of depression, education, and the aggressiveness of treatment for heart disease as possible explanations.
Kenneth Langa of the University of Michigan led a team of researchers who used data from the U.S. "Health and Retirement Study" and the "English Longitudinal Study of Ageing" to compare the brain health of elderly people from both countries.
"The better cognitive performance of U.S. adults was actually quite surprising, since U.S. adults had a higher prevalence of cardiovascular risk factors, which are generally associated with cognitive decline and poorer mental function," Langa said.
Subjects from both countries took tests of immediate and delayed recall of 10 common nouns such as hotel, river, tree, skin, gold, village, baby, and table. They heard the words spoken and were asked to repeat as many as possible immediately, then asked other survey questions, and finally were asked to repeat the words again five minutes later.
During the interview, participants were also asked what day, date, month, and year it was. Taken together, the answers (10 points for immediate recall, 10 for delayed recall, and 4 for orientation) were used to create 24-point scale of cognitive function.
The average score for the 8,299 American participants was 12.8, while the 5,276 English subjects averaged only 11.4 out of 24. This difference approaches the magnitude associated with about 10 years of aging.
In other words, 75-year-olds in the United States had memories as good, on average, as 65-year-olds in England.
"Higher levels of education and net worth in the U.S. probably accounted for some of the better cognitive performance," Langa said. "Furthermore, U.S. adults reported significantly lower levels of depressive symptoms than English adults."
He also cited trans-Atlantic differences in aggressiveness of cardiovascular disease treatment as possible explanations for the English adults' poor showing.
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