https://www.medpagetoday.com/neurology/dementia/73166?
- by Hazel Shahgholi Smith, MedPage Today Staff
Active participation in intellectual activities was associated with lower risk of subsequent dementia, according to a longitudinal, observational study of older Chinese adults followed for 7 years.
Odds for developing dementia were significantly lower in individuals who participated in daily intellectual activities, such as reading or playing cards (OR 0.71, 95% CI 0.60-0.84, P<0.001), reported Allen T. C. Lee, MBChB, of The Chinese University of Hong Kong, and colleagues.
"Dementia is a major public health concern worldwide. Finding ways to delay or prevent the clinical onset of dementia is now a key priority, as disease-modifying treatment is lacking, and populations are rapidly aging," they wrote in JAMA Psychiatry.
The authors singled out intellectual activities as a risk factor, independent of other lifestyle and health-related variables such as physical exercise, smoking, and nutritional habits. The association remained even when adjusted for participants that developed dementia between years 1-3 of study enrollment.
Tiers also existed for social/recreational pursuits (i.e., meeting friends and relatives), and other leisure activities (i.e., watching television), but they noted that "these activities are in general more passive and less cognitively demanding than intellectual activities," and therefore "we speculate that recreational and social activities might not be as effective as intellectual activities in preventing dementia."
Although almost all participants in the study reported participation in daily leisure activities, of the 14,233 participants who remained free of dementia, 67% reported daily participation in intellectual activities versus 51% in the group who went on to develop the disease.
No association was found between social or recreational activities and reduced risk of dementia. The authors stated that "given the very high level of participation in recreational and social activities in our cohort, a ceiling effect might mask any association with risk of dementia."
However, this finding suggests that "choosing the right type of activity appears to be more important than engaging in various non-intellectual activities in preventing dementia," they stated. Yet the study authors also acknowledged that their study design didn't permit any conclusions about causality.
Previous findings by the authors that mind-body and aerobic exercise placed an individual at a lower dementia risk remained "robust after controlling for intellectual activities." This combination of intellectual stimulation and good physical health led Lee's group to speculate that such practices improve cognitive reserve, but do so via differing mechanisms and "modulate the risk of dementia independent of each other."
Results showed that those that went on to develop dementia were older, predominately women, had lower educational attainment, more comorbidities, such as physical and psychiatric diagnoses, and less healthy diets.
Inclusion criteria included Chinese ethnicity, age >65 (median 74 at baseline), living in the community, and being free of dementia at baseline. Data were gathered from 15,582 individuals in Hong Kong initially evaluated in 2005 and followed through 2012. Just under two-thirds were women.
Dementia diagnoses was made by geriatric psychiatrists using ICD-10 criteria or a Clinical Dementia Rating of 1-3.
Health assessments both at baseline and follow-up involved the use of a nurse questionnaire to determine the frequency and type of leisure activity practiced by participants in the previous month.
A validated system was used to categorize leisure activities for older people. The intellectual branch of this system includes reading books, newspapers, or magazines, playing board games, Mahjong, or card games, and betting on horse racing. At year 3 after baseline, the proportion of participants who continued to practice daily intellectual activities was larger in those who remained free of dementia.
Lee's group advised caution in inferring a causal association between intellectual activity levels and incident dementia risk, due to the study design. There was also a risk of reverse causation, which was minimized but not completely excluded, they said.
Furthermore, they did not collect objective data on leisure activities or perform genotyping or neuroimaging. Finally, the results may not apply to older individuals of different ethnicities and with greater comorbidities.
In an accompanying editorial, Deborah Blacker, MD, ScD, of Harvard Medical School, and Jennifer Weuve, MPH, ScD, of the Harvard T. Chan School of Public Health, both in Boston, highlighted the issue of reverse causation, noting that the study participants may have disengaged from intellectual pursuits in the years, if not decades, preceding the diseases' manifestation because of slowly progressing cognitive decline.
However, Blacker and Weuve praised the authors for excluding those that developed dementia within the first 3 years of trial inclusion in an attempt to surmount this issue.
The digital explosion of online and downloadable "brain game" apps is a factor to consider, although it is not mentioned in the study directly. Of these investments, Blacker and Weuve recommend caution, "There is no evidence that such activities offer more benefit than picking up a book from a public library, a game of chess in the local park, a penny-ante poker game, or a wide variety of other highly cognitive but close-to-free activities on offer."
The study was supported by the Health and Health Services Research Fund of the Government of Hong Kong (2011).
Lee and co-authors disclosed no relevant relationships with industry.
Weuve disclosed support from the National Institute of Environmental Health Sciences and the National Institute on Aging (NIA). Blacker disclosed support from the NIA and the National Institute of Neurological Disorders and Stroke.
- Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College and Dorothy Caputo, MA, BSN, RN, Nurse Planner
last updated
Primary Source
JAMA Psychiatry
Source Reference: Lee ATC, et al "Association of daily intellectual activities with lower risk of incident dementia among older Chinese adults" JAMA Psychiatry 2018; DOI:10.1001/jamapsychiatry.2018.0657.Secondary Source
JAMA Psychiatry
Source Reference: Blacker D "Brain exercise outcomes: Does cognitive activity really work to maintain your brain?" JAMA Psychiatry 2018 DOI:10.1001/jamapsychiatry.2018.0656.
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