Current epidemiological approaches to the metabolic-cognitive syndrome.

In the last decade, cumulative epidemiological evidence suggested that vascular- and metabolic-based risk factors may be important in the development of mild cognitive impairment and dementia. Epidemiological and basic research have also proposed a model of cognitive impairment linked to metabolic syndrome (MetS) and metabolic disorders, suggesting for research purposes a "metabolic-cognitive syndrome" (MCS) in patients with MetS plus cognitive impairment of degenerative or vascular origin. In particular, MetS has been associated with the risk of age-related cognitive decline and vascular dementia, but contrasting findings also existed on the possible role of MetS in overall dementia and Alzheimer's disease. Among metabolic determinants of cognitive impairment, a better approach to the understanding of mechanisms could be to hypothesize a continuum leading to various degrees of late-life cognitive disorders in older subjects with metabolic-based risk factors. The MCS model could help us to explain the complex relationship between metabolic disorders and cognitive disturbances and the boundaries between normal and pathological conditions, with a better understanding of clinical and neuropathological features of these metabolic-based cognitive disorders. Strategies toward early and effective risk factor management could be of value in reducing the risk of MCS, so delaying the onset or preventing the progression of predementia syndromes. In the near future, clinical trials could be undertaken to determine if addressing MetS and metabolic-based risk factors, including inflammation, through lifestyle modification holds out the possibility of slowing down or ameliorating the cognitive aging process itself.