Today's 70-year-olds are as mentally sharp as 60-year-olds used to be

As we get older, our brains take a little longer to process information. Our memory might not be quite what it used to be.

Our cognitive abilities – like thinking, remembering and learning – often become somewhat weaker.

To what extent this happens varies from person to person.

Researchers have now also found differences between generations, as shown by a a new study.

A typical 80-year-old today is mentally sharper than 80-year-olds were at the start of this millennium.

Doing a lot of things right

The study is based on the Tromsø Study, an ongoing longitudinal population survey in Tromsø that started in 1974. Approximately 45,000 people have participated so far.

Researchers follow a large number of Tromsø inhabitants over time. Various physical measurements are recorded, and participants answer questions about their education, health, and lifestyle.

Using this data, the researchers have discovered that people have become healthier in the course of the last decades. Fewer people are dying from strokes and heart attacks than previously.

Older people are maintaining their mental acuity longer than before, according to a study carried out by Bente Johnsen and her colleagues.

“It’s good news that not only people’s physical health has improved, but also their cognitive health. We’re doing a lot of things right as a society,” Johnsen says.

She is a doctor and research fellow at the University Hospital of North Norway. The study is part of Johnsen's doctorate, which she will defend in November.

9,500 study participants

The Tromsø Study has expanded, adding new participants every seven years. Researchers have also included new types of data, making it possible to research more diseases and aspects of health.

“The fifth Tromsø survey started in 2001, when cognitive tests were added,” says Johnsen.

She and her colleagues have used data from approximately 9,500 people between the ages of 60 and 87.

The participants did cognitive tests in 2001, 2008, and 2015/2016. They were born between 1914 and 1956.

Memory and speed

It turned out that respondents who were born in later years generally scored better on the tests.

The participants took four types of tests. Two were word tests in which the participants were shown and had to remember 12 words. Then they had to remember these words when they were mixed with 12 new words.

In the third test, the participants had to connect numbers with symbols, which involved working memory, how quickly the brain works and having an overview of space and direction.

The last test was a psychomotor test, where the participants had to press a button as fast as they could, Johnsen explains. 

“It tested how quickly the brain is able to convert a command into a physical movement,” she says. 

More education and less smoking

The researchers observed that participants who were born in later years performed as if they were ten years younger.

The 70-year-olds in 2016 did as well as 60-year-olds in 2001. On one of the word tests, the age difference improvement was as much as 20 years.

The researchers looked at links between lifestyle and cognitive abilities to identify the reasons for the improvements.

“The clear winner is education. It had the most impact. We have more education now than before,” says Johnsen.

Increased height in people born later was also associated with better outcomes, especially among men.

“Height has been used in a lot of research as an indicator of good health and nutrition in childhood,” she says.

Physical activity and less smoking were also linked to the improvements.

Positive to drink moderately and often?

What was more surprising was that drinking alcohol was linked to improvements in cognitive health.

“Participants who drank small amounts often did better on cognitive tests than those who drank very often or not at all,” says Johnsen.

Other research has shown that alcohol has a negative effect on brain health.

The brain shrinks a little as we age. A study from 2022 showed that this happens a little faster if you drink two units of alcohol a day.

Another study has shown that several glasses of wine a week can cause too much iron in the brain. This finding correlates with poorer results on cognitive tests.

“Although the Tromsø Study showed that people who drank moderately and often fared well, it doesn’t mean that drinking makes you smart,” says Johnsen.

Other common factor

The participants who drank moderately and often most likely had something else in common that had a positive effect.

This is supported by the fact that the cognitive improvement was not linked to the amount of alcohol, but to the number of occasions. That is, cognition did not continue to improve the more people drank.

The authors of the study write that moderate drinking is linked to being socially active. According to a previous article from NTNU, being social and having relationships is one of the factors that contribute to keeping the brain healthy. A large international study from March 2023 also indicated that good social connections slow cognitive decline.

“We know from other surveys that a Mediterranean pattern of drinking, with one to two glasses of wine several times a week, is associated with more education and high income,” says Johnsen.

“We also know that people who don’t drink alcohol at all may have slightly poorer health for various reasons and test worse on cognitive tests for reasons other than abstinence.”

IQ of younger people is declining

Will improvement in cognitive health among the elderly keep growing?

“We’re not going to end up with everyone becoming super smart,” Johnsen says.

“I think we’re going to hit a ceiling.”

However, she believes we still have a lot to gain by continuing to live a healthy – or even somewhat healthier – life.

Studies have long shown that people's IQ has been improving. Decade after decade in the 20th century, people scored better on IQ tests than the previous generation at the same age – what is known as the Flynn effect.

This effect now appears to have reversed in Norway and other western countries, however. IQ scores are on the way down again.

A Norwegian study from 2018 showed that IQ scores among young men in military service have decreased starting with the cohort born in 1975.

Does this mean that when these cohorts turn 60, they will do worse on cognitive tests?

Johnsen says this is difficult to say. It is possible that the curve will flatten.

“It is also important to know that the military IQ tests are completely different tests than we used in the Tromsø study. We test somewhat different things,” she says.

Large and interesting study

Ellen Melbye Langballe heads the Ageing department at the Norwegian National Centre for Ageing and Health.

“This is a large and interesting study from Norway about possible differences in cognition and performance on cognitive tests among older people before and now,” Langballe wrote in an email to sciencenorway.no.

Langballe did not take part in the study, but points out that she has worked with Bjørn Heine Strand, who was part of the study. He is a researcher at the Norwegian Institute of Public Health and works part time at Norwegian National Centre for Ageing and Health.

Langballe writes that the findings probably reflect several social developments at the population level, such as the fact that nowadays more people have received an education.

“Changes in work task content, health behaviours, incidence of disease, health services and other social and cultural conditions that characterise the times we live in, could also be important influencing factors.”

The study results are in line with findings from international research, says Langballe.

Same trend in other Nordic countries

A 2020 study from Finland showed that the elderly have apparently become ‘younger’ since the 1990s (link in Norwegian).

Finnish 75- and 80-year-olds scored better on almost all physical and cognitive tests now than they did 30 years ago.

A Swedish study from 2018 showed that people in their 70s were mentally sharper than people of the same age in the 1970s.

Johnsen points out that the positive results in the study apply at population level.

“You can still become cognitively impaired even if you’ve done everything right.”

You might have lived a healthy life, exercised and had a high level of education – and still experience cognitive decline in your older years.

“And even if you’ve done everything ‘wrong,’ you might also be lucky and have good cognition.”

Discovered gender differences

Johnsen believes that gender differences that emerged in the study require more research.

“On three out of four tests, women do significantly better than men. We don't really have a good explanation for that,” says Johnsen.

“I think some of reason may have to do with education. Women previously had much lower levels of education, and now that has skyrocketed. But that’s not the whole explanation. We need more gender research on the topic.”

Reference:

Johnsen et al. Improved Cognitive Function in the Tromsø Study in Norway From 2001 to 2016, Neurology: Clinical Practice, vol. 11, 2021. DOI:  10.1212/CPJ.0000000000001115

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Read the Norwegian version of this article on forskning.no