Serum levels of hydroperoxides and multimorbidity among older patients with mild cognitive impairment or late-onset Alzheimer’s disease

Background: Oxidative stress (OxS) might be involved in the pathogenesis of late-onset Alzheimer disease (LOAD); noteworthy, the presence of multimorbidity is regarded as a common denominator of OxS and dementia. Aim: To evaluate the contribution of multimorbidity to OxS in LOAD and mild cognitive impairment (MCI). Methods: Serum hydroperoxides and multimorbidity (CIRS-CI scale) were evaluated in 46 Controls, 104 MCI and 75 LOAD. Results: A trend toward an increase of hydroperoxides from Controls to MCI to LOAD was observed (LOAD vs Controls p = 0.01). This OxS marker was positively and significantly correlated with CIRS-CI in Controls (p = 0.002) and patients with MCI (p = 0.005) but not in those with LOAD (p = 0.104). Conclusions: Multimorbidity is associated with systemic OxS but only in elderly people with either no or mild cognitive impairment. Although OxS is elevated in LOAD patients, its association with multimorbidity seems to be negligible, confirming the existence of strong disease-specific pro-oxidant mechanisms.