A recent study in Denmark compares the cognitive and physical functioning at age 95 of 1,584 individuals born in 1915 to the earlier performance of 2,262 individuals born in 1905 when they were 93 years old. People contacted to participate in this study were all Danish individuals still living in Denmark who were born in either 1915 or 1905. For both groups, 63 percent of those invited agreed to participate.
Looking at census data, the researchers determined that individuals born in 1915 were 28 percent more likely to live to the age of 93 and 32 percent more likely to reach age 95. Just under 50 percent of study participants in each group were in residential care at the time they were evaluated.
To assess the cognitive functioning of individuals at these ages, researchers gave participants three tests: the mini mental state evaluation, a cognitive test sensitive to age-related changes, and a measure of depression symptoms. For physical activity, participants were asked about their ability to perform activities of daily life, and had their grip strength, chair stand ability, and gait speed measured.
In the measures of psychological functioning, the average scores on the mini mental state evaluation and the test designed to measure age-related cognitive changes were significantly higher in the 95-year-old group born in 1915. However, the groups did not differ on the measure of depression symptoms. There were differences in educational attainment between the 1905 and 1915 groups, but these psychological differences between the two groups remained even after differences in educational differences were controlled for.
In terms of physical functioning, for activities of daily life 95-year-old individuals born in 1915 again scored significantly better than 93-year-olds born in 1905. For both groups, men scored significantly better than women on their ability to perform activities of daily life. In terms of measured physical performance, there was no difference between the groups on the measure of grip strength, but the 1915 group performed better than the 1905 group on both gait speed and on the chair stand.
Despite the group being two years older, the 1915 group consistently performed better than the 1905 group across a range of cognitive and physical tasks. This is encouraging evidence that for even the most elderly, a longer life is also accompanied by higher physical and cognitive functioning compared to the past.
Christensen K, Thinggaard M, Oksuzyan A, et al. Physical and cognitive functioning of people older than 90 years: a comparison of two Danish cohorts born 10 years apart. The Lancet (2013); 382(9903), 1507–1513.