Metabolic syndrome and cognitive disorders: is the sum greater than its parts?

Given the anticipated exponential increase in both the incidence and prevalence of dementia, it is critical to identify preventative strategies and improved treatments for this disorder. The metabolic syndrome is comprised of 5 cardiovascular risk factors that include abdominal obesity, hypertriglyceridemia, low high-density lipoprotein levels, hypertension, and hyperglycemia. The prevalence of the metabolic syndrome, similar to that for cognitive disorders, increases dramatically with age. Several possible mechanisms may explain an association between the metabolic syndrome and cognitive decline including microvascular and macrovascular disease, inflammation, adiposity, and insulin resistance. Although some of the individual components of the metabolic syndrome have been linked to risk of developing dementia and cognitive impairment, few studies have looked at the components of the metabolic syndrome as a whole. We found, in 3 separate studies involving elders of different ethnicities, that the metabolic syndrome is a risk factor for accelerated cognitive aging. This was especially true for elders with the metabolic syndrome and with elevated serum level of inflammation. If metabolic syndrome is associated with increased risk of developing cognitive impairment, regardless of mechanism, then early identification and treatment of these individuals might offer avenues for disease course modification.