Neuropsychology and neuroimaging in metabolic dysfunction

Within the last 20 years, the worldwide prevalence of obesity in industrialized nations has reached epidemic proportions. Nowhere is this more evident than in the USA. According to the Centers for Disease Control, in 1991, there were only four states with adult obesity prevalence rates above 15%. By 2007, however, there was only one state with less than 20% and 30 states had prevalence rates higher than 25% (CDC, Behavioral risk factor surveillance system survey data, 2008). The health consequences of obesity are many, and nearly all individuals with sustained obesity will develop metabolic dysfunction. In fact, the spectrum of health conditions that comprises metabolic dysfunction is most often etiologically linked to obesity and includes disruptions in the body's response to and production of insulin and resulting damage from hyperglycemia and hypoglycemia, hypertension, systemic inflammatory processes, and dyslipidemia-among others (Grundy et al, Circulation 112(17):2735-2752, 2005). These metabolic abnormalities tend to cluster together in the obese individual and are often referred to as metabolic syndrome (NCEP, JAMA 285:2486-2497, 2001). With a current prevalence of approximately 40% among individuals over 50 years of age (Ford, Diabetes Care 28:2745-2749, 2005), the costs associated with metabolic syndrome are significant. Analyses of Medicare expenditures indicate that individuals with metabolic syndrome incur 20-40% more health care costs over a 10-year period, representing a significant drain on the public health system in the USA (Curtis et al, Diabetes Care 30:2553-2558, 2007).