Moran et al.1reported that type 2 diabetes mellitus (T2DM) contributes to cognitive decline via neurodegeneration in an older cohort with low cerebrovascular disease burden. Although the data provided by Moran et al. are interesting, it is not clear whether the authors have properly controlled for other risk factors for cognitive decline such as hypertension. Relying solely on the T2DM diagnosis to ascertain cognition is an important limitation itself. Fasting blood glucose levels and duration of diabetes were not reported.