Pounding the Pavement: Is the Path to Brain Health Steeper for People Experiencing Greater Socioeconomic Deprivation?

Cognitive health has become a public health priority internationally with guidelines addressing this released by the World Health Organization [1] as well as calls for increased action on dementia prevention in countries including Australia [2].

Physical inactivity is a significant modifiable risk factor for dementia with a population attributable risk of 12.7% [3]. This highlights the importance of addressing physical inactivity to improve cognitive health and has led to the development of physical activity guidelines for older adults with subjective cognitive decline and mild cognitive impairment [4]. Despite the myriad benefits of physical activity for cognitive, mental, and physical health, much of the population does not meet the physical activity guidelines applicable to their age. This emphasizes the importance of research into factors that influence engagement in physical activity.

An individual’s level of cognitive function can influence preferences in engaging in physical activity as individuals with cognitive impairment are more likely to prefer “simple/light/safe activities” in “accessible” settings, and may be impacted by memory difficulties and lacking a companion [5]. Other factors such as ethnicity and the perspectives of carers also have an impact. For example, a qualitative study of 64 older Caucasian and Chinese Australians found differences in barriers and enablers to physical activity that were related to language and cultural issues [6]; and a survey of support persons of older adults, found high levels of awareness of the benefits of physical activity, and varied beliefs and preferences for physical activity programs for the person they were supporting [7]. There has been increasing recognition of the importance of social determinants of health although findings are not always consistent. Living in a disadvantaged neighborhood has been shown to be associated with decreased life expectancy and greater disability in remaining years of life [8]. In contrast, another study did not find that socio-economic status, income or the built environment had a significant impact on older adults engaging in physical activity [9].

Socioeconomic deprivation can be captured using individual-level indicators such as income or wealth, or through area-level indices which account for unemployment rate, education, crime and other social determinants of health [10]. Unsurprisingly, amongst those residing in more deprived neighborhoods, age adjusted mortality rates are higher than those in the least deprived areas, with this finding exacerbated by low education [10]. Both individual-level and area-level socioeconomic deprivation have been associated with the risk of incident all-cause dementia [11]. These findings suggest that interventions to prevent dementia may be especially relevant when targeted to households and areas with fewer socioeconomic resources.

For individuals looking to undertake free physical activity outside the home such as walking or jogging, neighborhoods which are unsafe, unclean, lacking in outdoor space or have obstacles or poorly maintained footpaths or sidewalks are barriers to undertaking physical activity in the local area [12]. Less favorable perceptions of the local environment of residents of low compared to high socio-economic status (SES) areas are due to these objective neighborhood features as well as the social cohesion in the area [13].

In light of this context, the study by Mc Ardle et al. [14] of the association of local area deprivation and physical activity in older adults with cognitive impairment is very timely. Mc Ardle et al. [14] explored the relationship between local area deprivation and physical activity in older people with cognitive impairment and cognitively healthy controls. Lower daily step count was associated with higher area deprivation in the controls and not individuals with cognitive impairment. Physical activity was assessed only via 7-day accelerometry, with no questionnaires used to characterize domain of physical activity (i.e., housing, transport, occupational, leisure time). Interestingly, despite the assumption that individuals with low SES status are less physically active than those of higher SES status, this observation may be restricted to the domain of leisure time physical activity [15]. While the study by Mc Ardle et al. [14] is unable to provide further insight into the impact of SES on different types of physical activity, it highlights the need for future research in this area to capture this information.

Of note, Mc Ardle et al. [14] demonstrated that lower SES impacted the physical activity levels of older adults who were cognitively healthy rather than those with cognitive impairment. One possible explanation for this finding is that cognitive impairment has a more significant impact on physical activity than SES, and this may be consistent with findings showing that this group of older adults prefer “simple/light/safe” activities [5]. Our anecdotal experience however is that older adults with cognitive impairment in higher SES environments may have means and access to environments that may provide more opportunities and support for physical activity, however this effect of SES was not shown in the findings in the study of Mc Ardle et al. [14]. This may relate to the lack of information regarding the type of physical activity being undertaken in this study or come back to the interpretation that the impact of cognitive impairment on physical impairment is so significant that the impact of other factors like SES is diminished.

The study by Mc Ardle et al. [14] is to be commended for shining a light on the importance of factors such as socioeconomic deprivation having an influence on physical activity levels in older adults with cognitive impairment. This study was limited by a relatively small sample size, and being secondary analysis, it lacked contextual details regarding the physical activity such as domain and location (i.e., inside the home or in the neighborhood). However, the findings provide helpful considerations in the design of future studies. There is a clear need for researchers, clinicians, and society as a whole, to focus more on social determinants of health and context in the investigation of factors influencing physical activity levels as well as the design of interventions. Future research could include qualitative studies that explore barriers and enablers for older adults experiencing socioeconomic deprivation, with a view to co-designing physical activity interventions that could then be evaluated in implementation trials. There also needs to be a focus on increasing representation of people from lower SES areas in research which is a more global imperative. In addition, the findings of the study by Mc Ardle et al. [14] also provide support to the importance of initiatives to promote dementia-friendly communities which are included in action plans both nationally, for example Australian [16], and internationally via the World Health Organization [17], which can also form part of future interventions.

It is hoped that future research and an increased whole of society focus will lead to interventions via health services, local community and national public health initiatives, being more able to target the groups of older adults that are most at risk, as well as tailor interventions to improve their effectiveness.