As the pathology progresses from preclinical stages through MCI to dementia, the concentrations of these molecules in biological samples change, along with increased expression of other risk factor-associated molecules which are involved in neuroinflammation (C1q), autophagy system dysregulation (cathepsin-D) and metabolic disorders (IRS-1 and p-IRS-1) [148]. Here, IRS1 is linked to dementia.