Edited by: Christian Gonzalez-Billault, Universidad de Chile, Chile
Reviewed by: Ramesh Kandimalla, Texas Tech University Health Sciences Center, United States; Alexei Verkhratsky, The University of Manchester, United Kingdom
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To effectively promote life-long health and resilience against – for example – neurodegenerative diseases, evidence-based recommendations must acknowledge the complex multidimensionality not only of the diseases but also of personal lifestyle. In a straightforward descriptive and heuristic framework, more than 50 potential lifestyle factors cluster around diet (D), education (E), exercise (E), and purpose (P), unveiling their many relationships across domains and scales. The resulting systematics and its visualization might be a small but helpful step toward the development of more comprehensive, interdisciplinary models of lifestyle-dependent risk and resilience and a means to explain the opportunities and limitations of preventive measures to the public and other stakeholders. Most importantly, this perspective onto the subject implies that not all lifestyle factors are created equal but that there is a hierarchy of values and needs that influences the success of lifestyle-based interventions.
Lifestyle-based health interventions promise solutions to pressing health problems by providing broad access to prevention and healthy aging. Preventing dementia is a prime target of these ambitions. After hundreds of failed clinical trials for treatments of neurodegenerative disease, especially of Alzheimer’s disease (AD) (
This step is wise, because despite the failing therapeutic trials, within age-cohorts the risk for AD has been decreasing over the past decades (
Given the complexity of the subject, one critical prerequisite is to first systematize the available knowledge. This is necessary, because “lifestyle factors” are a category without sharp boundaries and a common definition but with many stakeholder-specific connotations.
The proposed DEEP framework is a simple way to support, yet not replace, this process across domains, disciplines, and stakeholders. It consists of common language descriptors that in the absence of a unifying theory and a comprehensive model of lifestyle-dependent risk and resilience offer a systematic summary accessible to stakeholders across the professional disciplines and the public alike.
“Resilience” is here defined as the comprehensive ability to deal with adversity. Resilience is here not explicitly distinguished from “resistance,” which is often used to specifically identify the ability to ward off pathology. The term “lifestyle factors for risk and resilience” is a heuristic concept to structure the large group of potentially modifiable factors with proven or face value influence on health, that at least in theory can be influenced by the individual by his or her own actions. Actions based on these factors increase or decrease risk and reduce or promote resilience. Low levels of physical activity, for example, are associated with a shorter life expectancy and the increased incidence of cardiovascular disease, cancer, neurodegeneration, and other health issues (
The general usefulness of the term “lifestyle factors” notwithstanding, the heterogeneity of such factors and the conceptual and practical difficulty of capturing what people more broadly mean by “lifestyle” endanger the concept to become either too diffuse or too narrow. While in a scientific study context, lifestyle might have to be reduced to a manageable number of variables that can be measured and that show statistically significant correlations with outcome measures of interest (as well as relevant effect sizes), be it for example longevity or disease-free years, it is not trivial to answer the question of how these variables actually contribute to subjective “lifestyle.” The term “style” refers to this “how” and to rather personal ideas of “leading a good life.” “Lifestyle” is obviously much more than the sum of identifiable “lifestyle factors.”
To understand the impact of lifestyle it is thus not advisable to restrict consideration to only those factors for which the “best” evidence (i.e., large effect sizes in population studies) exists, such as those in the SNAP scheme, which only covers smoking, nutrition, alcohol, and physical activity (
In addition, studies by necessity have to single out identifiable factors for the sake of design, feasibility, and statistical power. There are also first combinatorial and multi-domain studies such as the FINGERS trial (
Dependent on stringency and definitions, at least 50 lifestyle risk and resilience factors can be identified (
Risk and resilience factors for neurodegenerative disease.
Basis of the framework is a four-field matrix with
The lifestyle factors, for whose effectiveness we have the best evidence, are some with the highest level of abstraction but with good measurability such as body weight or glucose levels. Education or physical activity cannot be measured directly but usually only be assessed via reductionistic proxies (e.g., VO2max for bodily fitness or self-reporting). For some factors in the P quadrant even qualitative proxies are a problem. But the P quadrant contains items that we would consider essentially human and which are determinants of well-being. To base our understanding of lifestyle solely on the relatively few quantifiable factors with “significant” effect sizes is as obviously incomplete as ascribing the genetic risk of complex disease only to the common polymorphisms with large effect sizes. Much like the “missing heritability” in the genetics of complex traits (
Appreciating complexity is not
The descriptive inclusiveness is also no argument against applying rigor and the full range of reductionistic instruments of evidence-based medicine to study the individual factors! Those approaches are mandatory for understanding effect sizes, weights of factors, and interaction effects.
Descriptions of lifestyle factors that are centered on diet, exercise, and cognitive activity/education might leave a blind spot exactly where many people would intuitively focus, when asked what matters most in life. Here, social and spiritual aspects rank very high: family and friends as well as mental and religious life, purpose, and autonomy. Certain “lifestyle” risk and resilience factors correspond to this preference: remaining in charge, the role of partnership and friendship, spirituality and religion, taking responsibility for others, etc. Such factors might exert a measurable impact: for example, positive beliefs about aging more or less compensated for the increased risk for AD associated with carrying the ApoEε4 polymorphism (
The dimension of Purpose-related factors is nevertheless often missing from the high-level aggregation in the discussion of “healthy lifestyle,” presumably because the evidence for these factors does not match the standards (of quantification) in the other domains. But for most people “health” in the sense of the medical professions is no end in itself. They intuitively have a broader, more implicit understanding, seamlessly integrating with “quality of life”: Leading a healthy life is more than the absence of disease. The concept of “successful aging,” otherwise not without its own problems (
In the DEEP scheme, key relationships between domains are emphasized and the communality of lifestyle factors, to which many studies have pointed (
The four quadrants can be paired in various, non-exclusive combinations (
Some of such interdependencies are known better than others and a few are widely acknowledged: the most obvious might be the relationship between energy intake and physical activity. Many studies calculate communalities, but what these interdependencies ultimately mean is rarely explored, especially for factors that are not linked in a way as obvious as in the case of caloric intake and expenditure. The classical triangle of (Mediterranean) diet, physical exercise, and cognitive activity/education also emphasizes potential links, but takes only three (albeit very important ones) out of an extensive network.
The step from the mere description in the DEEP scheme to a model of the network of factors requires different sets of data than presently available in most cases. Multivariate cohort studies, observational or interventional, can generate such data sets, if they collect information across all four DEEP quadrants.
The discrepancy between lifestyle in the public-health-centered sense of recommendations and programs for prevention (mostly found in the DEE quadrants) and in what most people would see as integral parts of their personal lifestyle (represented by the P quadrant) might help to explain why the implementation of lifestyle interventions is so difficult. Recommendations based primarily on what can be measured (body weight, blood pressure, caloric intake, VO2max, etc.) see lifestyle largely through the filter of basic needs. While these are critical foundations of lifestyle they only partly coincide with our personal hierarchy of needs.
Maslow’s hierarchy of needs, usually displayed in form of a pyramid, remains a very popular means to visualize the essential observation that we differently value the driving forces behind our actions and, by extension, our lifestyle (
Recommendations focusing on what can be measured might hence come across as superficial and trivial (
This implies that a holistic consideration of lifestyle risk and resilience factors along the DEEP scheme might help to develop causal models as basis of individualized strategies for healthy (cognitive) aging and the prevention of (neurodegenerative) disease. Interventions with large demonstrated effect sizes would obviously still be prioritized, but their practical realization and their contextual embedding would be improved by individualized multi-factorial approaches.
Physical activity, for example, remains the preventive “super factor” with massive effect sizes across many domains. Realizing its potential alone would profoundly change health and disease in any population. And most people know that they should (and actually would like to) be more physically active: there is no lack of insight and intentions. The implementation, however, of seemingly simple interventions based on reducing sedentary lifestyle and increasing physical activity is extremely difficult. Exercise-based programs often show remarkably little long-term effects on lifestyle. The same applies to nutritional recommendation, which are popular and often have high face validity. But dietary interventions are notoriously difficult to study, the underlying metabolic mechanisms to which these interventions refer show great inter-individual genetic differences, and eating food is much more than nutrition.
Measures centering only on single or few habits become isolated from the contexts of the individual’s life. New habits that were formed in the lab lack anchoring in everyday life.
Good and bad habits are context-sensitive and circumstances trigger habitual behaviors. Changing habits is difficult, if the world around us reinforces them. The question is, to which extent circumstances can be changed. While there is no general answer to this, there will be room for individual solutions that adapt lifestyle to conditions at hand and explore the available room for development. The DEEP scheme visualizes the scope of such co-factors.
The large cohort studies and meta-analyses indicate that the identifiable factors with large effect sizes are not independent of each other. On one side this suggests that an abstract “super factor” might be identifiable, comparable to the G factor in intelligence.
On the other hand, however, the communalities also indicate that there is more than one road to Rome. They might hide the range of options for the individual to achieve his or her goals.
The DEEP scheme might suggest that the greatest reduction in risk and the greatest level of resilience is found in individuals with a somewhat balanced nature within and between the four quadrants (
Working from the center and the intended result of “leading a good life,” including the full spectrum of our needs and values, is one way of altering contexts to our benefit. Ironically, despite being much more complex, multi-factorial changes might be more successful and ultimately easier: small steps at a time, but along different directions (as indicated in the many options of the DEEP scheme), might ultimately be more efficient and effective than focusing on one high-gain domain alone. They would lead to a diversification of the individual portfolio of lifestyle risk and resilience.
No datasets were generated or analyzed for this study.
GK conceived the concept presented in this article, collected the relevant information, and wrote the manuscript.
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
The table lists potential lifestyle resilience factors for neurodegenerative disease, independent of whether the cited publications are referring to the risk or resilience side of the factor.
+ | Smoking is associated with an increased risk of dementia. | Meta-analysis | |||
+ | Elderly smokers have increased risks of dementia and cognitive decline. | Meta-analysis of prospective studies | |||
Avoid environmental risk factors | (+) | There is at least moderate evidence implicating the following risk factors: air pollution, aluminum, silicon, selenium, pesticides, vitamin D deficiency, and electric and magnetic fields. | Systematic review | ||
Avoid air pollution from traffic | + | Living close to heavy traffic was associated with a higher incidence of dementia, but not with Parkinson’s disease or multiple sclerosis. | Population-based cohort, |
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No substance abuse | (+) | Hyperphosphorylated tau and amyloid precursor protein deposition is increased in the brains of young drug abusers. | Post-mortem case–control study | ||
(+) | Former use of benzodiazepines could be a risk factor for dementia. | Nested case–control study | |||
+ | Benzodiazepine use is associated with an increased risk of Alzheimer’s disease (AD). | Case–control study | |||
+ | Out of the 10 studies retrieved, 9 reported an increased risk of dementia in benzodiazepine users. | Systematic review | |||
+ | High proportion of alcohol-related dementia in early-onset dementia. | Systematic review | |||
+ | Middle-aged adults with a history of alcohol use disorders have increased odds of developing severe memory impairment later in life. | Prospective cohort study (19 years, 6500 participants) | |||
+ | Alcohol use disorders were a major risk factor for onset of all types of dementia, and especially early-onset dementia. | Retrospective cohort study (20 years, 31 Mio. patients) | |||
+ | The results show a greater risk of dementia in those who abstain from alcohol or consume >14 units/week, with risk increasing in a linear fashion at higher levels of consumption. | Prospective cohort study (23 years, |
One of the key studies supporting the idea that low alcohol consumption might be beneficial. | ||
(+) | Several cross-sectional and longitudinal population-based studies suggested a protective effect of coffee, tea, and caffeine use against late-life cognitive impairment/decline. | Systematic review | |||
(+) | Daily tea drinking is associated with decreased risk of cognitive impairment, MCI, and cognitive decline in the elderly. However, the association between tea intake and AD remains elusive | Meta-analysis, 52,503 participants | |||
Sufficient hydration* | +/– | Inconsistent evidence of the impact of dehydration on cognitive performance. Current findings in the field suggest that particular cognitive abilities and mood states are positively influenced by water consumption. | Review | Drinking sufficient amounts of water is a popular advice, but backed by limited evidence. Because dehydration promotes delirium and thus can aggravate dementia, especially in care settings, this factor nevertheless has good face validity. | |
Vitamins, trace elements, antioxidants | ? | Value of vitamin D substitution in cognitive impairment remains doubtful. | Systematic literature research and meta-analysis | ||
+ | Within the range of a habitual dietary intake, higher intake of lignans is associated with less cognitive decline at middle age. | Retrospective cohort study | Example of the large class of polyphenols. | ||
? | Findings do not consistently show habitual intakes of dietary antioxidants and are associated with better cognitive performance or a reduced risk for dementia. | Systematic review | |||
+ | Vitamin E intake, from foods or supplements, is associated with less cognitive decline with age. There was little evidence of association with vitamin C or carotene intake. | Longitudinal population-based study | The WHO found the available evidence sufficient to recommend against the use of vitamin substitution in its 2019 guidelines. | ||
+ | In an older population, a Mediterranean diet supplemented with olive oil or nuts is associated with improved cognitive function. | Randomized clinical trial | |||
+ | Pooled results suggest that a higher adherence to the MeDi is associated with a reduced risk of developing MCI and AD, and a reduced risk of progressing from MCI to AD. | Systematic review | |||
+ | Significant gaps in the literature regarding total cholesterol and late-life dementia remain. Evidence suggests that high midlife total cholesterol increases risk of late-life AD, and may correlate with the onset of AD pathology. | Meta-analysis, |
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+ | Higher glucose levels may be a risk factor for dementia, even among persons without diabetes. | Prospective study | |||
+ | Underweight, overweight, and obesity in midlife increase dementia risk. | Meta-analysis of 15 prospective studies, |
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+ | Studies investigating the association between midlife BMI and risk for dementia demonstrated generally an increased risk among overweight and obese adults. When measured in late-life, elevated BMI has been associated with lower risk. In addition, being underweight and/or having a decrease in BMI in late-life are associated with higher dementia risk compared to BMI in the normal range or stable BMI. | Review | |||
+ | Being underweight in middle age and old age carries an increased risk of dementia over two decades. | Retrospective cohort study, |
Controversial study that contradicts some conclusions from other studies in that no effect of overweight was reported. | ||
Hormone replacement | – | Estrogen plus progestin therapy increased the risk for probable dementia in postmenopausal women aged 65 years or older. In addition, estrogen plus progestin therapy did not prevent mild cognitive impairment in these women. These findings, coupled with previously reported WHI data, support the conclusion that the risks of estrogen plus progestin outweigh the benefits. | There is still considerable controversy regarding this conclusion, but there is no clear evidence in favor of the idea that hormone therapy lowers the risk for dementia. | ||
+/− | There is no convincing evidence from the trials identified that blood pressure lowering in late-life prevents the development of dementia or cognitive impairment in hypertensive patients with no apparent prior cerebrovascular disease. | Meta-analysis (Cochrane), |
No clear case can yet be made for interventions at older age. | ||
+ | Elevated blood pressure during midlife, persistence of elevated blood pressure into late life, and, among non-hypertensives, a steep decline in blood pressure during mid- to late-life were associated with an increased dementia risk in a community-based cohort. Our data highlight the potential sustained cognitive benefits of lower blood pressures in mid-life and also suggest that declining blood pressure in older adults with prehypertension or normotension, but not in those with hypertension, may be a risk marker for dementia. | Retrospective study, |
This study highlights the complex relationship between control of blood pressure and the risk of dementia. | ||
+ | In this cohort of older adults, increased numbers of optimal cardiovascular health metrics and a higher cardiovascular health score were associated with a lower risk of dementia and lower rates of cognitive decline. These findings may support the promotion of cardiovascular health to prevent risk factors associated with cognitive decline and dementia. | Population-based cohort study; |
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Reduce TV consumption | + | High television viewing and low physical activity in early adulthood were associated with worse midlife executive function and processing speed. | Prospective 25-year study | TV consumption represents the largest part of average sedentary behaviors. | |
Non-exercise activity thermogenesis (NEAT)* | (+) | NEAT is a highly variable component of daily total energy expenditure and a low level of NEAT is associated with obesity. NEAT enhances lifestyle, and variations in individual and environmental factors can significantly affect daily energy expenditure. | Review | No data directly related to neurodegeneration and brain function exist. | |
Avoid head injury | + | Although further research is needed, these 10 findings suggest that dose-dependent effects of violent head displacement in vulnerable brains predispose to dementia. | Review | ||
(+) | Meta-analysis revealed a significant association of prior TBI with subsequent dementia. | Meta-analysis, |
The authors come to the opposite conclusion because the effect here disappeared for individual neurodegenerative diseases (Simpson’s paradox). | ||
+ | History of TBI, including mild TBI, is associated with the development of neurological and psychiatric illness. This finding indicates that either TBI is a risk factor for heterogeneous pathological processes or that TBI may contribute to a common pathological mechanism. | Meta-analysis | Increased pooled odds ratios for “dementia,” Parkinson’s disease, AD, and other disorders. | ||
Prevent falls* | (+) | n/a | n/a | n/a | Preventing the disabling consequences of falls supports the positive effects of physical activity. Currently no studies exist on falls as modifiable risk factor for neurodegeneration. |
Balance training | (+) | Balance training intervention […] was effective in improving balance and mobility, […]. Cognition did not decline during the course of the intervention but did decline following the intervention, suggesting a possible protective effect. | Prospective study | ||
+ | Meta-analyses of prospective studies documented a significantly reduced risk of dementia associated with midlife exercise; similarly, midlife exercise significantly reduced later risks of mild cognitive impairment in several studies. | Review of meta-analyses and other reports | |||
+ | We found a higher level of physical activity to be associated with a lower risk of dementia. | Prospective, population-based study (Rotterdam Study), |
One of the key long-term population studies, supporting the claim. | ||
+ | This meta-analysis suggests that physical activity interventions positively influence cognitive function in patients with dementia. | Meta-analysis, |
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Muscular strength training | (+) | All studies concluded that cognitive function and grip strength declined, on average, with increasing age, although with little to no evidence for longitudinal associations among rates of change. | Systematic review | ||
+ | High-intensity progressive resistance training results in significant improvements in cognitive function, muscle strength, and aerobic capacity in older adults with MCI. Strength gains, but not aerobic capacity changes, mediate the cognitive benefits of progressive resistance training. | Randomized, double-blind, double-sham controlled trial; |
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+ | Resistance training significantly improved global cognitive function, with maintenance of executive and global benefits over 18 months. | Randomized, double-blind, double-sham controlled trial; |
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Exergames (physically active video games) | Exergames significantly improved global cognition. | Meta-analysis of 17 randomized controlled trials, |
Control groups are physically active. | ||
Walking groups* | (+) | Walking groups are effective and safe with good adherence and wide-ranging health benefits. | Systematic review and meta-analysis, 1843 patients, including PD patients | Outcome measure: general health, depression score, VO2max. It is unclear, at present, how much of the observed effect can be attributed to physical activity |
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Flexibility training* | n/a | n/a | n/a | Flexibility is one of the three pillars of physical activity (besides endurance and strength), but its contribution to prevention of dementia and neurodegeneration has not yet been studied. | |
Tai Chi | (+) | Compared with usual physical activities, Tai Chi shows potential protective effects on healthy adults’ cognitive ability. | Systematic review of prospective controlled trials, |
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Sexual activity* | (+) | There were significant associations between sexual activity and number sequencing and recall in men. | Cross-sectional study, |
Protective effects of sexual activity are a popular assertion in the media with a certain face validity and some evidence from studies, but currently still backed by insufficient data. | |
(+) | After controlling for demographic and health-related lifestyle factors, more frequent sexual activity and greater emotional closeness during partnered sexual activity were associated with better memory performance. | Prospective study, |
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Meditation and mindfulness | (+) | All studies reported significant increases in gray matter volume in the meditators/intervention group, albeit in assorted regions of the brain. Limited research exists on the mechanisms through which meditation affects disease-related neurodegeneration, but preliminary evidence suggests that it may offset gray matter atrophy. | Review | ||
Avoid stressors | (+) | Higher event-based stress ratings collected over the follow-up period were associated with faster cognitive decline in subjects with mild cognitive impairment but not in cognitively normal subjects. | Prospective study, |
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Yoga | (+) | Based on the available literature, it could be concluded that yoga might be considered as an effective adjuvant for the patients with various neurological disorders. | Review | ||
Music and dance | + | Playing a musical instrument was significantly associated with less likelihood of dementia and cognitive impairment. | Twin study, |
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+ | Recent and past musical activity, but not general lifestyle activities, predicted variability across both verbal and visuospatial domains in aging. […] Early age of musical acquisition, sustained and maintained during advanced age, may enhance cognitive functions and buffer age and education influences. | Cross-sectional case control study, |
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+ | Among leisure activities, reading, playing board games, playing musical instruments, and dancing were associated with a reduced risk of dementia. | Prospective cohort, |
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E Education | |||||
Sleep | + | Sleep disturbances may predict the risk of incident dementia. | Systematic review and meta-analysis, |
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Avoid noise | (+) | Increases in dementia risk were also observed with […] night-time noise levels. | Retrospective cohort study, |
The association did not remain significant in multipollutant models. | |
Compensated midlife hearing loss | ? | When completed in 2022, Aging and cognitive health evaluation in elders study should provide definitive evidence of the effect of hearing treatment versus education control on cognitive decline in community-dwelling older adults with mild-to-moderate hearing impairment. | Multicenter randomized controlled trial, |
Ongoing trial. | |
+ | Hearing loss is independently associated with accelerated cognitive decline and incident cognitive impairment in community-dwelling older adults. | Prospective observational study, |
The WHO found the available evidence insufficient to recommend treating hearing loss in its 2019 guidelines. | ||
+ | Comparing participants with moderate/severe hearing impairment to participants with no hearing impairment, 20-year rates of decline in memory and global function differed by −0.47 standard deviations ( |
Cross-sectional and longitudinal analysis in a prospective study, |
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Level of education | (+) | Lower education was associated with a greater risk for dementia in many but not all studies. The level of education associated with risk for dementia varied by study population and more years of education did not uniformly attenuate the risk for dementia. It appeared that a more consistent relationship with dementia occurred when years of education reflected cognitive capacity, suggesting that the effect of education on risk for dementia may be best evaluated within the context of a lifespan developmental model. | Systematic review | ||
Languages | + | Lifelong bilingualism confers protection against the onset of AD. | Retrospective study on AD patients, |
Childhood bilingualism, which has been assessed here, is not identical to the popular assertion that learning a new language later in life is protective! | |
+ | Our results suggest a positive effect of bilingualism on later−life cognition, including in those who acquired their second language in adulthood. | Population-based cohort study, |
Sixty-five participants learned the second language after the age of 18 years. | ||
(+) | We did not find that bilingualism protects from cognitive decline or dementia from prospective studies. | Systematic review and meta-analysis | The conclusion is controversial, because the retrospective studies in the analysis did show the association. | ||
Reading | + | Among leisure activities, reading, playing board games, playing musical instruments, and dancing were associated with a reduced risk of dementia. | Prospective cohort, |
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Lifelong learning | + | More frequent cognitive activity across the life span has an association with slower late-life cognitive decline. | Longitudinal cohort study, |
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Cognitive stimulation | + | Frequent participation in cognitively stimulating activities is associated with reduced risk of AD | Longitudinal cohort study (“Nun study”), |
Screened activities included: viewing television; listening to radio; reading newspapers; reading magazines; reading books; playing games such as cards, checkers, crosswords, or other puzzles; and going to museums. | |
Environmental enrichment | + | The longitudinal evidence consistently shows that engaging in intellectually stimulating activities is associated with better cognitive functioning at later points in time. | Review | Extensive review of the overarching concept, comprising many aspects covered elsewhere here. | |
Playing board games | + | Among leisure activities, reading, playing board games, playing musical instruments, and dancing were associated with a reduced risk of dementia. | Prospective cohort, |
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Volunteering | (+) | Cohort studies showed volunteering had favorable effects on depression, life satisfaction, wellbeing but not on physical health. These findings were not confirmed by experimental studies. Meta-analysis of five cohort studies found volunteers to be at lower risk of mortality. | Systematic review | ||
(+) | Our results largely support the assumptions that voluntary work in later life is associated with lower self-reported cognitive complaints and a lower risk for dementia, relative to those who do not engage, or only engage episodically in voluntary work. | Population-based cohort study (registry study), |
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+ | Volunteering at the initial assessment and volunteering regularly over time independently decreased the risk of cognitive impairment over 14 years, and these findings were maintained independent of known risk factors for cognitive impairment. | Panel survey, |
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Socio-economic status | + | Significant interactions were found between a healthful lifestyle (defined as having more than or equal to three healthful lifestyle factors) and income on changes of global cognition and verbal fluency […]. The protective effect of a healthful lifestyle was observed only among participants with lower income in global cognition and logical memory […]. | Prospective cohort study, |
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+/− | Occupational social class was not statistically significantly associated with dementia death in men or women. | Meta-analysis, of 11 prospective cohort studies, |
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Artistic and craft activities | + | The risk [of MCI] was reduced with engagement in artistic, craft, and social activities in both midlife and late life. | Population-based prospective cohort study, |
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Spiritual life and religion | (+) | Study results show an inverse association between religious attendance in 1982 and cognitive dysfunction in 1985. | Population-based cohort study, |
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(+) | Religious attendance may offer mental stimulation that helps to maintain cognitive functioning in later life, particularly among older depressed women. | Population-based cohort, study, |
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+ | Spirituality and religion appear to slow cognitive decline, and help people use coping strategies to deal their disease and have a better quality of life. | Systematic review | |||
Religious life-style | (−) | The prevalence of dementia was increased among men with exclusively religious education and among those with the most strict observance. In both cases, these associations were not altered appreciably after controlling for sociodemographic confounders. | Longitudinal cohort study (Israeli Ischemic Heart Disease study), |
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Personality | (+) | Using brief assessments of personality and cognition, we found robust evidence that personality is associated with risk of cognitive impairment and dementia in a large national sample. | Population-based, longitudinal study, |
Personality traits are to some extent amenable to volitional change ( |
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+/− | Neuroticism increased risk for dementia, and conscientiousness reduced risk. The protective effect of openness was tentative. Extraversion and agreeableness were not associated with dementia. | Systematic review and meta-analysis, |
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Intelligence | + | Compared to the highest intelligence group (≥115), dementia risk was raised in the lowest-scoring category (<85) and these associations were stronger for women […] than men […]. There was evidence of a dose–response association between childhood IQ and dementia in women […] but not in men […]. | Population-based cohort study (1932 Scottish Mental Survey), |
Relevance of intelligence as modifiable risk and resilience factor relies on the question, whether intelligence can be improved, which despite many claims to the contrary remains questionable ( |
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Positive attitudes toward aging | + | In the total sample those with positive age beliefs at baseline were significantly less likely to develop dementia, after adjusting for relevant covariates. Among those with APOE ε4, those with positive age beliefs were 49.8% less likely to develop dementia than those with negative age beliefs. | Prospective cohort study | ||
Optimism | + | Optimism was prospectively associated with a reduced likelihood of becoming cognitively impaired. | Prospective cohort study, |
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No or treated depression | + | The literature suggests an association between depression and dementia, and growing evidence implies that timing of depression may be important to defining the nature of the association. | Review | The WHO found the available evidence insufficient to recommend treating depression in its 2019 guidelines. | |
− | Depressive symptoms in the early phase of the study corresponding to midlife, even when chronic/recurring, do not increase the risk for dementia. Along with our analysis of depressive trajectories over 28 years, these results suggest that depressive symptoms are a prodromal feature of dementia or that the two share common causes. The findings do not support the hypothesis that depressive symptoms increase the risk for dementia. | Population-based cohort study (Whitehall II), |
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Connected-ness, avoid social isolation | + | Living alone [relative risk ratio (RRR) = 5.814; |
Cross-sectional study, |
The WHO found the available evidence insufficient to recommend social activity in its 2019 guidelines. | |
+ | Feeling lonely rather than being alone is associated with an increased risk of clinical dementia in later life and can be considered a major risk factor. | Prospective cohort study, |
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Marital status | + | We confirmed an association between marital status and AD, with an excess risk observed among never-married individuals. | Population-based cohort study, |
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+ | Those living alone as non-marrieds may be at risk for early-onset and late-onset dementia. | Prospective population-based study, |