Study raises questions about role of leisure activity in dementia

Studies have suggested that taking part in leisure activities such as playing cards or gardening may be associated with a lower risk of developing dementia. But a new study found no association between taking part in leisure activities at age 56 and the risk of dementia over the next 18 years. The researchers also found that some people who are later diagnosed with dementia stop participating in leisure activities years before they are diagnosed. The study is published in the October 28, 2020, online issue of Neurology, the medical journal of the American Academy of Neurology.

"Of course there are many reasons to participate in leisure activities, and this finding does not question the importance of keeping active for general health and well-being, but it does suggest that simply increasing leisure activity may not be a strategy for preventing dementia," said study author Andrew Sommerlad, Ph.D., of University College London in the United Kingdom. "Our study suggests that changes in the amount of leisure activity may be an early sign of dementia, possibly due to symptoms such as apathy or other social changes or early cognitive difficulties."

The study involved 8,280 people with an average age of 56 years who were followed for an average of 18 years. Their participation in leisure activities was assessed at the beginning of the study, five years later and again 10 years later. Researchers reviewed health records to identify people who developed dementia.

Leisure activities included reading, listening to music, taking classes, participating in clubs, visiting friends and relatives, playing cards or games, taking part in religious activities and gardening. People were placed in low, medium and high groups based on their participation levels.

During the study, 360 people developed dementia. The overall rate of dementia was 2.4 cases for 1,000 person-years. Person-years take into account both the number of people in the study and the amount of time each person spends in the study.

The researchers found no relationship between taking part in more leisure activities at the beginning of the study and having a lower dementia risk nearly 20 years later. There was only a relationship when leisure activity participation in late life was assessed. People who took part in more leisure activities at the average age of 66 were less likely to have dementia diagnosed over the next eight years than people who had lower participation.

With every one standard deviation increase in leisure activities, equivalent approximately to doing three new leisure activities monthly or two activities weekly, people were 18% less likely to be diagnosed with dementia 8 years later. These results took into account other factors that could affect risk of dementia, such as diabetes, high blood pressure and body mass index.

In addition, people whose level of participation dropped over the course of the study were more likely to develop dementia than those whose participation level stayed the same over the years. Of the 1,159 people whose activity decreased, 53, or 5%, developed dementia, compared to 17 of the 820 people, or 2%, whose activity level stayed low over the years.

"More research is needed to confirm these results, but we know that early changes in the brain can start decades before any symptoms emerge," Sommerlad said. "It's plausible that people may slow down their activity level up to 10 years before dementia is actually diagnosed, due to subtle changes and symptoms that are not yet recognized."

A limitation of the study was that dementia diagnoses were gathered from electronic health records rather than assessing each participant, so some cases may not have been diagnosed.