In the late 19th century, American men lived to the age of 40 and women to 48 on average; a number that has now stretched to 76 years for men and 81 for women.
We are living much longer lives, but not only are our bodies becoming more resilient, our minds are following suit as well. In fact, a comprehensive study out of Denmark has found that people who reach their 90s today show improved mental performance compared to people in the same age group born ten years earlier.
Using the Danish Civil Register System, lead researcher Kaare Christensen, professor of epidemiology at the University of Southern Denmark in Odense and director of the Danish Aging Research Center, and colleagues found all nonagenarians living in Denmark. In 1998, they assessed 2,262 men and women born in 1905; then in 2010, they assessed 1,584 men and women who were born in 1915. The first group was tested when they were 92 and 93 years old, the second group when they were 94 and 95.
The assessment included physical tests such as grip strength, chair stand and gait speed, as well as cognitive measurements of attention, verbal memory and word fluency.
The results? Those who were born in 1915 lived longer than those born in 1905, which conforms to life expectancy trends; but they also scored significantly better on measures of cognitive ability and daily living activities.
Even after adjusting for increases in education in a decade, people born in 1915 "still performed better in the cognitive measures, which suggests that changes in other 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," notes the study which was published in The Lancet.
The people born in 1915 scored better than those born in 1905 in basic activities like walking inside and outside, getting out of bed and going up and down stairs. They also outperformed those born in the prior decade on cognition tests, even though they were several years older at the time of the assessment.
"That's not to say that everyone in the later cohort was healthy, smart and functioning well, but compared to those who were born 10 years earlier, not only were more living to a higher age, but they were functioning better," Christensen says.
"If this development were to continue, the future functional problems and care needs of very elderly people might be less than are anticipated on the basis of the present-day burden of disability," the study concludes.
Related stories on MNN: