Significantly higher levels of cotinine, the main metabolite of nicotine, were found in the MCI group compared to ND (Figure ). Interestingly, tobacco smoking has been correlated with a lower incidence of AD. Cotinine has shown to prevent memory loss and inhibit Aβ aggregation without the toxicity and addictive properties of its precursor (nicotine) . However, since no lifestyle information was available in this study, this cannot be interpreted further at this stage.