Source: Neuroscience & Biobehavioral Reviews

Neurodegenerative disease is attributed in roughly equal parts to genetic risks present at birth and modifiable risk factors, such as air pollution or brain injury, which differ between age groups and populations. Risk factors can interact, but the calculation of synergistic risk is complicated, so the standard approach is to present the marginal risk as partitioned between the individual causative factors. The Lancet Commission on dementia prevention, intervention, and care established 12 modifiable risk factors and described bidirectional interactions between delirium (which can arise from infectious disease) and dementia.

Prion diseases, such as Creutzfeldt-Jakob disease, are rare, rapidly fatal neurodegenerative diseases that can be sporadic, inherited, or iatrogenic.1 The ability of aggregated misfolded cellular proteins to spread from person to person has sparked fear and intrigue in the medical community for decades. Unlike viruses and other infectious agents, extant literature suggests that the transmissibility of prion proteins is not easy and typically requires extraordinary events. These events are most commonly medical procedures that contain contaminated cadaveric human growth hormone (hGH) replacements or dural grafts.