Dementia prevention review

Dementia Prevention: Methodological Explanations for Inconsistent Results. Nicola Coley, Sandrine Andrieu, Virginie Gardette, Sophie Gillette-Guyonnet, Caroline Sanz, Bruno Vellas, and Alain Grand. (2008). Epidemiol Rev 30 (1): 35-66.

Abstract: “The prevention of neurodegenerative dementias, such as Alzheimer disease, is a growing public health concern, because of a lack of effective curative treatment options and a rising global prevalence. Various potential risk or preventive factors have been suggested by epidemiologic research, including modifiable lifestyle factors, such as social contacts, leisure activities, physical exercise, and diet, as well as some preventive pharmacologic strategies, such as hormone replacement therapy, nonsteroidal antiinflammatory drugs, and Ginkgo biloba. […] The aim of this paper is to review the epidemiologic data linking potential protective factors to dementia or cognitive decline and to discuss the methodological limitations that could explain conflicting results. A thorough review of the literature suggests that, even if there are consistent findings from large observational studies regarding preventive or risk factors for dementia, few randomized controlled trials have been designed specifically to prove the protective effects of interventions based on such factors on dementia incidence. Because of the multifactorial origin of dementia, it appears that multidomain interventions could be a suitable candidate for preventive interventions, but designing such trials remains very challenging for researchers.”

Below are excerpts from the section “Social contacts, leisure activities, and physical exercise.” (Dance integrates all of these aspects: social engagement, leisure and cognitive activity, and physical exercise).

Prospective longitudinal studies
“Social contacts and social engagement. Fourteen studies have found an inverse relation between the level of late-life social contacts or engagement and the risk of dementia/Alzheimer disease (76–82) or cognitive decline (83–89). Midlife social engagement was assessed by one of these studies (82) but was not found to be related to dementia risk.
Two studies (90, 91) found only certain measures of social engagement to be associated with better cognitive function, and four studies found no association between participation in social activities (92, 93) or social network or support measures (91, 94) and cognition.

“Cognitive activities in late life. Twelve studies have demonstrated a relation between increased participation in cognitive activities in late life and a decreased risk of dementia (76–78, 95), Alzheimer disease (95–98), vascular dementia (95), or cognitive decline or impairment (87, 92, 93, 97,99, 100). No studies were identified that failed to find an association between cognitive activities and outcomes, although the positive effects in one of the above-mentioned studies (87) were seen only in some specific cognitive domains.

“Physical exercise. An increased frequency or intensity of physical exercise or activities in late life was associated with a decreased risk of dementia/Alzheimer disease (76, 77, 95, 101–107) or cognitive decline/impairment in 19 studies (87, 104, 108–115). However, nine studies found no association with dementia/Alzheimer disease (78, 96,97, 116, 117) or cognitive decline/impairment (92, 118–120). Two studies examined the effects of midlife physical exercise on the risk of dementia in late life and found conflicting results (121, 122).”

Physical activity in preventing and managing Alzheimer’s disease

The Role of Physical Activity in the Prevention and Management of Alzheimer’s Disease—Implications for Ontario. Ontario Brain Institute. (2013).

“Approach: To better understand how physical activity can contribute to the prevention and management of Alzheimer’s disease, 871 research articles were reviewed. After closer inspection and quality scoring, 24 randomized control trials and 21 prospective cohort studies examining physical activity and Alzheimer’s disease were selected for further analysis.

“Results: Within older adults with Alzheimer’s disease, regular physical activity improved quality of life (QOL), activities of daily living (ADL), and decreased the occurrence of depression. In older adults without Alzheimer’s disease, those who were very physically active were almost 40% less likely to develop Alzheimer’s disease as those who were inactive. At the population level, it was observed that more than 1 in 7 cases of Alzheimer’s disease could be prevented if everyone who is currently inactive were to become physically active at a level consistent with current activity recommendations. On this basis, potential cost-savings (~$88 to $970 million CDN per year) in healthcare for community-dwelling older adults with Alzheimer’s disease are substantial.” (page 2)

Promoting successful cognitive aging

Enrichment effects on adult cognitive development; Can the functional capacity of older adults be preserved and enhanced?. Hertzog, C., Kramer, A. F., Wilson, R. S., & Lindenberger, U. (2008). Psychological Science in the Public Interest, 9(1), 1-65.

Some excerpts from the abstract:

“We begin with a theoretical framework that emphasizes the potential of behavior to influence levels of cognitive functioning. According to this framework, the undeniable presence of age-related decline in cognition does not invalidate the view that behavior can enhance cognitive functioning.

“We conclude that, on balance, the available evidence favors the hypothesis that maintaining an intellectually engaged and physically active lifestyle promotes successful cognitive aging.

“The longitudinal evidence consistently shows that engaging in intellectually stimulating activities is associated with better cognitive functioning at later points in time. Other studies show that meaningful social engagement is also predictive of better maintenance of cognitive functioning in old age. These longitudinal findings are also open to important rival explanations, but overall, the available evidence suggests that activities can postpone decline, attenuate decline, or provide prosthetic benefit in the face of normative cognitive decline, while at the same time indicating that late-life cognitive changes can result in curtailment of activities.

“Third, there is a parallel literature suggesting that physical activity, and aerobic exercise in particular, enhances older adults’ cognitive function. Unlike the literature on an active lifestyle, there is already an impressive array of work with humans and animal populations showing that exercise interventions have substantial benefits for cognitive function, particularly for aspects of fluid intelligence and executive function. Recent neuroscience research on this topic indicates that exercise has substantial effects on brain morphology and function, representing a plausible brain substrate for the observed effects of aerobic exercise and other activities on cognition.”

Dance therapy for aging & dementia: compiled research

The American Dance Therapy Association has a Bibliography of Dance/Movement Therapy with Aging and Dementia. Compiled by Lenore Wadsworth Hervey, Ph.D., ADTR, September, 1996 / Updated, 2000 / Updated, 2007 by Heather Hill & Christine Hopkins.

Lower risk of dementia

Leisure Activities and the Risk of Dementia in the Elderly. Joe Verghese, M.D., Richard B. Lipton, M.D., Mindy J. Katz, M.P.H., Charles B. Hall, Ph.D., Carol A. Derby, Ph.D., Gail Kuslansky, Ph.D., Anne F. Ambrose, M.D., Martin Sliwinski, Ph.D., and Herman Buschke, M.D. (2003). New England Journal of Medicine, 348: 2508-2516.

In the study of 469 people, “Dancing was the only physical activity associated with a lower risk of dementia.”

Participants were interviewed starting in 1980 about their participation in “6 cognitive activities (reading books or newspapers, writing for pleasure, doing crossword puzzles, playing board games or cards, participating in organized group discussions, and playing musical instruments) and 11 physical activities (playing tennis or golf, swimming, bicycling, dancing, participating in group exercises, playing team games such as bowling, walking for exercise, climbing more than two flights of stairs, doing housework, and babysitting).” (Table of the various activities).

The study found that “There was no association between physical activity and the risk of dementia. Exercise is said to have beneficial effects on the brain by promoting plasticity, increasing the levels of neurotrophic factors in the brain, and enhancing resistance to insults. Cognitive and physical activities overlap, and therefore it is not surprising that previous studies have disagreed on the role of physical activities. Although physical activities are clearly important in promoting overall health, their protective effect against dementia remains uncertain.” (See the footnotes in the article for references for each of those sentences.)

Dance movement therapy for dementia

Dance movement therapy for dementia (Protocol). (2014). Karkou V and Meekums B. Cochrane Database of Systematic Reviews 2014, Issue 3. *There is not free open access to the review.

“The objectives are as follows:

1. To assess the effects of DMT on behavioural, social, cognitive and emotional problems of people with dementia in comparison to no treatment (waiting list), standard care or any other treatment.
2. To compare different forms of DMT (e.g. Laban-based DMT, Chacian DMT or Authentic Movement).”