Promoting the Assessment of Physical Activity and Cardiorespiratory Fitness in Assessing the Role of Vascular Risk on Cognitive Decline in Older Adults

The world population has been experiencing significant aging processes that have resulted in rising proportions of older persons in the total population since the mid-twentieth century. It is estimated that by 2025 there will be 1.2 billion people over 60 years of age and by 2050 there will be 2 billion, with 80% in developing countries (World Health Organization, 2011) Moreover, the recent (Alzheimer's Disease International., 2018) indicates that over 50 million people live with dementia worldwide, which is expected to exceed 152 million by 2050. There is no known cure for dementia and, thus, preventative strategies are of great importance. In fact, the annual cost of dementia care was expected to exceed $1 trillion by 2018, thereby, primary prevention is currently considered a potential tool to delay the disease onset by modulating modifiable risk factors. In fact, it has been suggested around 35% of dementia is attributable to a combination of nine modifiable risk factors, including education, hypertension, obesity, hearing loss, depression, diabetes, physical inactivity, smoking, and social isolation (Livingston et al., 2017). In line with that, three potential brain mechanisms through which preventative strategies may reduce dementia risk are: (a) reduced brain damage (vascular, neurotoxic and oxidative stress), (b) reduced brain inflammation, and (c) increased brain cognitive reserve with greater physical activity (PA) and exercise suggested as a common factor to promote all these mechanisms (Livingston et al., 2017). Therefore, greater PA and fitness (especially cardiorespiratory fitness, CRF) are currently considered key factors to promote in the prevention of cognitive decline and dementia (Kennedy et al., 2017; Livingston et al., 2017; Muller et al., 2017). Moreover, these key factors not only directly affecting cognitive decline and dementia, but also have effect through their mediation effects on other related risk factors, such as hypertension, obesity, depression, and diabetes (Chase et al., 2009; Kokkinos et al., 2017; Celis-Morales et al., 2018; Chekroud et al., 2018; Ortega et al., 2018). Particularly well-established in the literature is the role of PA and CRF on cardiovascular (CV) risk factors and diseases (CVD), as well as mortality (Blair et al., 1998; Jimenez-Pavon et al., 2016; Ortega et al., 2018). However, studies analyzing the role of vascular risk on cognitive decline have been based solely upon the use of the Framingham Heart Study general cardiovascular disease score (i.e., Framingham Risk Score (FRS) (Eldholm et al., 2018; Rabin et al., 2018), and no studies have investigated the potential mediation effect of PA and CRF on the vascular risk of cognitive decline and dementia. Hence, we believe that to better understand the relationship between vascular risk and cognitive decline, assessment of PA and CRF should be included when determining an individual's vascular risk factors. Therefore, the purpose of this opinion article is to encourage the assessment of PA and fitness, at least CRF, when studying the role of vascular risk on cognitive decline.