The most unwelcome sign of aging, cognitive decline, may begin as young as 45, researchers found.
Scores on memory, reasoning and fluency tests fell starting in the mid-to-late 40s in a study of more than 7,000 U.K. government workers, said researchers led by Archana Singh-Manoux at France’s Centre for Research in Epidemiology and Population Health in Villejuif, near Paris. The findings were published online today in the British Medical Journal.
The deterioration became more dramatic as people aged, the researchers found. Pinpointing when cognitive decline begins is important because treatment is more likely to work when memory and reason first start to wane, they said. Most dementia studies focus on people 65 and older and future research should look at younger groups, wrote Francine Grodstein, an associate professor of medicine at Brigham and Women’s Hospital in Boston, in an editorial accompanying the study.
“This finding potentially has profound implications for prevention of dementia, and public health,” Grodstein said. “Efforts to prevent dementia may need to start in adults as young as 45.”
Scientists in the U.K., France and the U.S. followed 5,198 men and 2,192 women participating in the Whitehall II study, a health-research project so called because those recruited worked at government offices in and around Whitehall in London.
All the office workers were between 45 and 70 when the cognitive study began. Over a decade, the participants were tested three times on memory, reasoning, vocabulary and fluency.
For men and women ages 45 to 49, reasoning declined 3.6 percent over a decade, the study found. Men ages 65 to 70 experienced a 9.6 percent drop, while women in that age group had a 7.4 percent decrease, the researchers said. Vocabulary was the only area where test scores didn’t fall, they said.
The findings may not apply to the general population, since Whitehall II participants are mostly men and mostly white-collar workers with fairly stable jobs, the researchers said. Further study is needed, they said.
“Life expectancy continues to increase, and understanding cognitive aging will be one of the challenges of this century,” the researchers wrote. “Better understanding of both adverse and healthy cognitive aging trajectories might help the identification of early risk factors,” which may include obesity and cardiovascular disease, they said.
The study was funded by the European Science Foundation, the U.S. National Institutes of Health, the BUPA Foundation, the Academy of Finland, the U.K. Medical Research Council and the British Heart Foundation.