Type 2 Diabetes Mellitus and Alzheimer's Disease: Overlapping Biologic Mechanisms and Environmental Risk Factors

Purpose of ReviewA number of studies over the past two decades have suggested that type 2 diabetes mellitus (T2DM) patients are at an increased risk of Alzheimer's disease (AD). Several common molecular pathways to cellular and metabolic dysfunction have been implicated in the etiology of both diseases. Here, we review the emerging evidence from observational studies that investigate the relationship between T2DM and AD, and of shared environmental risk factors, specifically air pollution and pesticides, associated with both chronic disorders.Recent FindingsParticulate matter and traffic-related air pollution have been widely associated with T2DM, and multiple studies have associated exposures with AD or cognitive function. Organochlorine (OC) and organophosphate (OP) pesticides have been associated with T2DM in multiple independent populations. Two populations have observed increased risks for OC and OP exposures and AD. Other studies, limited in exposure assessment, have reported increased risk of AD with any pesticide exposure assessments.SummaryThis may suggest shared pathogenic pathways between environmental risk factors, T2DM, and AD. Research focusing on exposures related to both T2DM and AD could provide new disease insights on shared mechanisms and help shape innovative preventative measures and policy decisions.