Mentally stimulating activities and risk of dementia
Higher levels of daily intellectual activities predict lower risk of dementia. But do people with greater intellectual activities also embrace other healthy behaviors, such as increased physical activity, eating a better diet, and not smoking, which could account for the lower risk of dementia? Researchers addressed this question with data from 15,582 participants aged 65 and older (median age 74 years at baseline) who attended Elderly Health Centers in Hong Kong. Intellectual activities (reading books, or newspapers, or magazines; playing board or card games; or betting on horse races) were distinguished from social activities (joining a social center, participating in voluntary work, meeting relatives or friends, attending religious activities), and from other activities (watching TV, listening to radio, shopping, going to a teahouse).
After a median follow-up of 5 years and after accounting for confounding factors, participants who remained free of dementia engaged in more leisure activities and engaged in more intellectual activities at baseline than participants who did not. Plus, participants who remained free of dementia maintained nearly the same level of intellectual activities from baseline to the end of follow-up, while the level of social activities declined significantly. After excluding participants who developed dementia during the first 3 years of follow-up (to minimize the risk of reverse causation), participants who engaged in daily intellectual activities had 29 percent lower odds of developing dementia during the remaining 2 years of follow-up, even after accounting for age, educational level, and depression, among other factors. Thus, active engagement in intellectual activities might help you lower your risk of dementia.
Leisure activities may not protect against dementia
A systematic review and meta-analysis published in 2016 found that greater leisure time activity predicted lower risk of subsequent dementia. Dementia usually appears after a long pre-clinical period during which time cognitive decline might reduce participation in leisure time activities. Thus, declining levels of leisure time activities might actually be a result of cognitive decline, rather than a cause of subsequent dementia. European researchers used data from 8,202 participants with an average of 56 years at baseline who were followed for an average of 18 years in three waves of the Whitehall II Study to test this idea. At baseline, participants reported on a scale of 0 to 3 if and how often they engaged in 13 categories of leisure activities. The composite leisure activity score ranged from 0 (no engagement) to 39 (high engagement). During 18 years of follow-up, higher leisure activity scores did not significantly predict lower risk of developing dementia. However, higher leisure activity scores for older participants (average age 66 years) predicted significantly lower risk of dementia over 8 years of follow-up. Decline in leisure activity scores during follow-up predicted significantly greater risk of developing dementia. The authors concluded that decline of leisure activities arose from pre-clinical dementia and not from any protective effect of leisure activities.
What did a recent systematic review and meta-analysis show?
As of 2022, the results of studies that evaluated the links between leisure time activities and risk of dementia produced conflicting results, as you saw above. Researchers conducted a systematic review and meta-analysis of 38 longitudinal studies to gain a wider perspective on this issue. Leisure time activities were categorized as cognitive or physical or social. Thirty-two of the studies were rated as high quality, while 6 were rated as medium quality. Higher levels of cognitive, physical, and social activities predicted significantly lower risk (23, 17, and 7 percent, respectively) of developing all-cause dementia. Higher levels of cognitive and physical activities predicted significantly lower risk (34 and 13 percent, respectively) of developing Alzheimer’s dementia. Higher levels of physical activities predicted significantly lower risk (23 percent) of developing vascular dementia. Of note, only 4 studies included social activities, of which 2 did not show positive results. In addition, socially active people might engage in more cognitive and physical leisure activities, muddying the water. Overall, this meta-analysis suggested that all types of leisure time activities might reduce the risk of developing dementia.
Mentally stimulating activities and cognitive decline
The average age of people in developed countries is increasing with potential increase in the prevalence of cognitive decline, a harbinger of dementia. Researchers at University College London used data from 43,687 participants in the European Survey of Health, Ageing, and Retirement (SHARE) to determine if people who engaged in cognitively stimulating activities would have a slower pace of cognitive decline. Participants were age 50 years or older at baseline and formed representative samples of 12 European countries in the fourth, fifth, and sixth waves of SHARE. Cognitively stimulating activities (CSAs) were categorized as: 1) attending an educational or training course; 2) reading books, magazines or newspapers, 3) completing crossword puzzles or Sudoku, and 4) playing games such as chess or cards. Participants received a score of 1 for every category in which they engaged in the 12 months prior to baseline, resulting in an overall CSA score from 0 to 4. Cognitive function at baseline was evaluated for verbal fluency and memory.
Cross-sectional analyses showed that both verbal fluency and memory declined notably from about age 55 to age 80. For each CSA category, participants who reported activity in that category had higher verbal fluency and memory scores than participants who reported no activity. Of the four categories, reading books, magazines or newspapers had the strongest positive effect on verbal fluency and memory. Effects tended to be greater for women than men. Positive effects of all four CSA categories were usually greater for participants with low and opposed to high education. Europeans who engage in a variety of cognitively stimulating activities may reduce their rate of decline in verbal fluency and memory thereby slowing the rate of overall cognitive decline.
More recent research
Older people who enrich their lives with mentally and/or socially stimulating activities may build a cognitive reserve and reduce their risk of dementia. Researchers in Australia used data from 10,318 community-dwelling participants in generally good health with a median age of 74 years and without cognitive impairment in the ASPREE Longitudinal Study of Older Persons to test this idea. The 19 measures of leisure activities were consolidated into 7 categories including adult literacy, creative artistic, active mental, passive mental, interpersonal networks, social activities, and external outings.
Participants reporting higher levels of adult literacy (writing letters, journaling, using a computer), active mental (playing games, cards, chess), creative artistic (craftwork, painting, drawing), passive mental (reading books or magazines, watching TV) categories had significant 11, 9, 7, and 7 percent lower dementia risk of developing dementia during follow-up. These results accounted for factors associated with dementia risk. This study reinforces results of other studies that documented lower dementia risk for participants who used crossword puzzles, played chess, and played cards. Perhaps the mental concentration required for such pursuits promoted positive neurostructural changes. Unexpectedly, social activities and interpersonal networks did not reduce reduced dementia risk, possibly because the participants were highly socially engaged at baseline and were not likely to improve their social engagement very much.
What to do
Find enjoyable ways to Keep Learning (such as the examples listed above) to reduce your risk of dementia and maintain your well-being. Incorporate at least one of the above-mentioned mentally stimulating activities into your daily life. If you’re already doing that, pick one more activity. You have many possible choices.
