Association of Daily Intellectual Activities With Lower Risk of Incident Dementia Among Older Chinese Adults

This study asked 15,582 community-living Chinese patients aged 65 years or older about their intellectual activities, including reading books, newspapers, or magazines; playing board games, Mahjong, or card games; and betting on horse racing, for the month before baseline and subsequent evaluations.

At baseline, they were free of dementia and were evaluated over 5 years. Those with any of the indicated intellectual activities had a lower risk of developing dementia over time (OR, 0.71; 95% CI, 0.60–0.84; P < .001). Logistic regression controlled for demographics (age, sex, and educational level), physical and psychiatric comorbidities (cardiovascular risks, depression, visual and hearing impairments, and poor mobility), and lifestyle factors (physical exercise, adequate fruit and vegetable intake, smoking, and recreational and social activities). Patients who developed dementia within 3 years after baseline were excluded. Also excluded were patients with low for education-adjusted MMSE scores and those living in care (nursing) homes.

Geriatric psychiatrists diagnosed patients using the ICD-10 criteria as the outcome. The ICD-10 identifies dementia by a decline in: 1) memory; 2) cognitive function such as planning, organizing, or processing information; and 3) emotional control or motivation. I expect that geriatric psychiatrists are very adept at identifying patients with cognitive deficits. Yet, the possibility exists that some early baseline dementia was missed, leading to the association of declining participation in intellectual activities and dementia. When I ask families about the timing of the onset of cognitive deficits, I most commonly get the answer of 6 months ago. Upon further probing, mom has usually stopped cooking Thanksgiving dinner 2 years earlier, and dad has stopped driving 2 years ago. This study has tried to control for this by eliminating patients who were diagnosed with dementia within 3 years. I hope the investigators will continue to follow this cohort for long-term follow-up to look for a trend of increasing or decreasing differences between the groups over time.

The investigators made concerted efforts to include patients who did not follow up, including seeing them at home. The groups differed significantly in all the major parameters that have been found to contribute to dementia (HTN, DM, heart disease, depression, poor mobility, vision, and hearing loss) or protect from dementia (physical activity, fruit and vegetable intake). The biggest difference was among the intellectual activities with an odds ratio of 0.71, followed by physical exercise (OR, 0.79).

The authors discuss recent findings that cognitive training is associated with enhanced functional connectivity between the hippocampus and superior frontal cortex, whereas physical training is associated with positive structural plasticity, such as increased cortical thickness of the posterior cingulate and reversed progression of white matter hyperintensities.

Although previous studies have shown some positive effects, others have shown only benefits by “training patients for the test.” Likewise, several studies have shown exercise to be beneficial, yet others showed no benefit. This well-done study will change my practice in that I will recommend my patients to include intellectual activities in addition to exercise for prevention of dementia.