NEW YORKMaking it to 90 may not guarantee your health and sensibilities remain intact. However, a new study shows people lucky enough to live that long may have better brain health than their predecessors.
Published July 10 in The Lancet, the study found that on tests of mental abilities, a group of 95-year-old Danes scored better than a group of Danes born 10 years earlier, who had been tested when they were about the same age.
For the study, researchers compared data from Danes who were born either in 1905 or 1915, giving them physical and mental tests and interviews to assess their abilities to recall information, carry out daily living tasks, symptoms of depression and overall mental health state.
They found 23 percent of seniors in the 1915 group scored in the highest category on a standardized cognitive test, compared to 13 percent of the earlier-born group. Out of the 30 questions and tasks, members of the later-born group averaged two more correct responses than the earlier-born group did.
Why the better mental performance? It wasn't just better education, but beyond that the researchers could only guess at things like more intellectual stimulation and healthier diets earlier in life.
"Factors such as nutrition, burden of infectious disease, work environment, intellectual stimulation and general living conditions also play an important part in the improvement of cognitive functioning," said the study's authors, led by Dr. Kaare Christensen, head of the Danish Aging Research Center of the University of Southern Denmark in Odense.
More people are living to such old ages. The U.S. census counted 425,000 Americans age 95 and older in 2010, a 26 percent increase over the total in 2000.
The mental testing compared 1,814 elderly Danes examined in 1998 to the later-born group of 1,247 Danes tested in 2010. The researchers also found that later-born Danes were better able to carry out basic living tasks like getting out of bed or a chair. So, they were functioning better overall, the study concluded.
Christensen said he imagines that in the future, Danes who live into their 90s will continue to be better off than their predecessors. He was cautious about applying the results to the United States, although he said the availability of education in the U.S. after World War II would be a plus.
Dr. James Pacala, associate head of the department of family medicine and community health at the University of Minnesota Medical School who didn't participate in the study, said he suspects the same trends are present in the United States. He also said the findings fit with previous work that shows people are functioning better at given ages than they used to.
But Pacala, who heads the board of the American Geriatrics Society, noted that even in the better-functioning group of Danes, at least 40 percent and probably more had dementia.
In a linked commentary published in the same issue of The Lancet, researchers at Radboud University Medical Center in Nijmegen, Netherlands pointed out that some of the more alarming public health predictions focus around the expected sharp rise in dementia prevalence for the elderly.
Rising rates of dementia in the United States has had health officials bracing for a "silver tsunami" for years, as the aging baby boomer population has begun to reach their senior years.
A February study in Neurology found the, climbing from 4.7 million patients in 2010 to 13.8 million by 2050. Based on life expectancy estimates, the researchers calculated about 7 million of these people will be at least 85 years old by 2050.
"The evidence for improved cognition at very old age provided by Christensen and colleagues challenges these extrapolations," wrote professors Marcel Olde Rikkert and Rene Melis of Radboud University Medical Centre in Nijmegen, Netherlands, in the commentary.