Plasma levels of insulin and amyloid β 42 are correlated in patients with amnestic mild cognitive impairment

Epidemiological and experimental data suggest that type 2 diabetes (DM2) and sporadic late-onset Alzheimer's disease (AD) share a common mechanism, that is able to produce accumulation of insulin and amyloid β 42 (Aβ42), the major pathogenic events respectively of the two conditions. In 71 non diabetic patients with amnestic mild cognitive impairment we found a significant linear correlation between fasting plasma levels of insulin and Aβ42 (R = +0.25, P < 0.05). The levels of both peptides were elevated in comparison to 48 age-matched cognitively normal controls. The correlation of insulin and Aβ42 plasma levels suggests a pathogenic link between DM2 and sporadic AD.