Vascular Risk Factors and Cognitive Function: The Effect of Aging Process

During last 20 years, several epidemiological and experimental studies have linked vascular risk factors with cognitive decline and dementia, including Alzheimer’s disease, in old age. Yes this association changes across lifetime. In fact, high blood pressure and obesity at midlife have been associated with greater age-associated cognitive decline, while dementia onset in old age is often heralded by lowering of blood pressure and body mass index. Part of this seemingly paradoxical association can be explained by reverse causation, as damage of specific brain areas can impair blood pressure (insula, amygdala) and fat mass (hypothalamus) control. On the other hand, autonomic nervous system dysfunction, mainly age-associated baroreflex response impairment and orthostatic hypotension, may have a pathogenic role in brain damage. Other vascular risk factors maintain their cognitive prognostic role lifelong, harmful for insulin resistance and protective for aerobic physical activity. Age-associated loss of muscle mass (sarcopenia) can contribute to insulin resistance, resulting in faster neurodegeneration, and, conversely, accumulation of neuropathological lesion has been associated with muscle mass decline over time. Pharmacological treatment of vascular risk factors at midlife is warranted to prevent cognitive decline, but should be less aggressive in older, cognitively impaired patients, more vulnerable to adverse events. Physical activity should be recommended lifelong, both as primary prevention and as adjuvant treatment in dementia.