For a study, researchers sought to determine how aging and type 2 diabetic Mellitus (T2DM) interacted with brain glucose metabolism, individual metabolic connections, and network dynamics. About 83 patients with T2DM (40 old and 43 middle-aged) and 69 sex-matched healthy control individuals (HCs) (34 elderly and 35 middle-aged) had 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance scanning in a two-by-two factorial design. Individual metabolic connections and networks were built using Jensen-Shannon divergence. Graph theoretical analysis was used to quantify the topological aspects of the networks. The general linear model was primarily employed to evaluate the interaction impact of aging and type 2 diabetes on glucose metabolism, metabolic connectivity, and network. 

Aging and T2DM impacted glucose metabolism, metabolic connectedness, and regional metabolic network characteristics (all P<0.05). Post-hoc analyses revealed that, compared to old HCs and middle-aged T2DM patients, elderly T2DM patients exhibited lower glucose metabolism, higher metabolic connectivity, and regional metabolic network characteristics in cognition-related brain regions (all P<0.05). Fasting plasma glucose and age were shown to have negative relationships with glucose metabolism and favorable correlations with metabolic connectivity. Elderly T2DM patients showed glucose hypometabolism, stronger functional integration, and higher information communication efficiency, all of which were mostly situated in cognition-related brain areas. Changes in metabolic connection patterns may be compensatory for glucose hypometabolism.