Active participation in intellectual activities, such as reading and playing board games or card games, may delay or prevent dementia in older adults, even if these activities take place in late life, new research suggests.
Investigators studied more than 15,000 adults aged 65 years and older for up to 7 years and found that those who reported participating in intellectual activities were less likely to develop dementia, even after adjusting for health behaviors, physical and psychiatric comorbidities, and sociodemographic factors.
"Lifestyles are important modulators for cognition in later life," senior author Linda C. W. Lam, MD, professor, Department of Psychiatry, Chinese University of Hong Kong, told Medscape Medical News.
"With this large sample, we were able to control for other physical and lifestyle confounders; therefore, our findings give robust evidence that the benefits of intellectual activities are independent of physical health status," she said.
The study was published in the July issue of JAMA Psychiatry.
"Increasing evidence suggests that active participation in intellectual activities...can help reduce the risk of dementia among older adults," the authors write.
However, it is unclear whether the intellectual activity per se is protective against dementia or whether other factors are involved. Individuals who engage in intellectual activities typically engage in more health-promoting activities, such as engaging in exercise, eating a balanced diet, and refraining from smoking.
Moreover, intellectual activities "often encompass a mixture of cognitive, social, and recreational components," so it is hard to tease out whether the cognitive training, social engagement, or positive experience is the contributor to better cognitive health.
Although previous studies excluded people with dementia at baseline, people in preclinical stages of dementia may have already experienced difficulties in intellectual activities and curtailed their involvement in such activities.
"Such reverse causation might introduce bias in the observed association," the authors note.
"What motivated us to conduct this study is that we were inspired by healthy older adults who remained active in the community, as well as by literature supporting benefits of lifestyle activities on cognition," Lam reported.
The researchers studied community-living individuals aged ≥65 years (n = 15,582) who presented to the Elderly Health Centers of the Department of Health in Hong Kong from January 1 to June 30, 2005.
Participants had to be free of stroke, Parkinson's disease, and dementia and had to have scored higher than the education-specific cutoff on the Cantonese version of the Mini–Mental State Examination at baseline.
Participants were followed for up to 6 years (median, 5 years; interquartile range, 3.0 - 6.0 years). Incident clinical dementia was the outcome.
"Intellectual activities" consisted of reading books, newspapers, or magazines; playing board games, Mahjong, or card games; and betting on horse racing.
"Social activities" consisted of joining a social center, participating in volunteer work, meeting relatives or friends, and attending religious activities.
"Other recreational activities" consisted of watching television, listening to the radio, shopping, and going to a teahouse.
The researchers assessed variables such as demographics (age, sex, and educational level), physical and psychiatric comorbidities, and lifestyle factors (regular physical exercise, current smoking, and consumption of fruits and vegetables).
Optimizing Cognitive Reserve
The individuals who developed incident dementia during the study period (n = 1349; 8.7%) tended to be older than those who remained dementia free. The patients who developed dementia were predominantly female and had lower educational attainment, and the prevalence of physical and psychiatric comorbidities was higher in these patients.
Additionally, they engaged in healthy lifestyle practices to a lesser degree than those who remained dementia free, although there was no significant difference in the prevalence of smoking between the two groups.
Although almost all participants (n = 15,574) reported engaging in some type of daily leisure activities, those who remained dementia free engaged in more varieties of leisure activities at baseline than those who developed dementia (three vs two activities; P < .001), and a larger proportion engaged in intellectual activities (66.9% vs 50.7%; P < .001).
The two groups did not differ in the proportion of participants who engaged in social or recreational activities.
Older age, female sex, and lower educational level were associated with fewer types of activities at baseline.
There was no change in the frequency of participation in leisure activity from baseline to year 3 among participants who developed incident dementia at years 4 to 6. Almost all individuals continued to report engagement in leisure activity daily over the years.
Additionally, there was no increase in disengagement from intellectual activities over time prior to the clinical onset of dementia.
A higher proportion of those who remained dementia free reported participating in intellectual activities 3 years after baseline in comparison with those who developed dementia during years 4 to 6.
When the researchers excluded participants who developed dementia 3 years after baseline (n = 588) or those who could not be confirmed to be free of dementia by year 3 owing to missing follow-up (n = 3483), they still found that those who remained dementia free performed more activities at baseline than did those who developed dementia (three vs two activities; P < .001).
Moreover, the proportion of participants who participated in daily intellectual activities but not recreational or social activities at baseline was significantly larger in the cognitively stable group.
Even after controlling for demographics, physical and psychiatric comorbidities, lifestyle factors, and other types of leisure activities, the estimated odds ratio (OR) for incident dementia remained significantly lower in those participating in intellectual activities daily (OR, 0.71; 95% confidence interval, 0.60 - 0.84; P < .001).
"We were not surprised to find that intellectual activities help to maintain cognition," Lam said.
"We postulated that intellectual activity optimizes cognitive reserve and enhances compensatory activities, although available evidence does not suggest that intellectual activity has a direct impact on primary neuropathological hallmarks, such as amyloid plaque or tau in Alzheimer's disease," she added.
She said that intellectual activity is "especially relevant as [an] alternative strategy [that] could be solicited, and even better if it acts beyond the basic neurodegeneration process."
Don't Jump to Conclusions
Commenting on the study for Medscape Medical News, Deborah Blacker, MD, ScD, geriatric psychiatrist and epidemiologist, professor of psychiatry at Harvard Medical School and of epidemiology at Harvard T. H. Chan School of Public Health, and director of the Gerontology Research Unit at Massachusetts General Hospital, Boston, who as not involved with the study, pointed to several "important strengths, including the study's large sample size and that the researchers went out of their way to have a range of cognitive activities that are not necessarily associated with education."
However, Blacker, who is the coauthor of an accompanying editorial, raised some important caveats.
"[The study] has a little bit of jumping to conclusions because it's credible and you want to believe it, but some questions remain unanswered," she said.
One concerns causation. "What you think is the outcome — a lower incidence of dementia — might actually be the cause, since people who are beginning to have cognitive trouble may curtail their activities, which is reverse causation."
Moreover, it is unclear whether these findings generalize beyond the study population in China to populations in other countries.
She added that there is not enough evidence in this study to justify recommending expensive "brain game" programs to prevent dementia in older adults.
"There are many cognitive activities that are enjoyable and don't cost money and at minimum will enrich the person's life, and might also help the brain along the way," she said.
Lam added, "Clinicians will be able to offer concrete advice as to leisure activity scheduling for people with subjective [or] objective cognitive complaints with risks for developing dementia."
The study was supported by the Health and Health Services Research Fund of the Government of Hong Kong. Dr Lam and coauthors have disclosed no relevant financial relationshiips. Relevant financial relationships of Dr Blacker and her coauthor, Jennifer Weuve, MPH, ScD, are listed with their editorial.
Medscape Medical News © 2018
Cite this: Daily Intellectual Activity May Prevent, Delay Dementia - Medscape - Jul 09, 2018.