Table 1.

Present and future of descriptive epidemiology and population-based studies in neurodegenerative diseases

Descriptive epidemiology issues	Present	Future
Diagnosis of disease	Mainly based on clinical criteria	Based on clinical and biological criteria
Disease definition in projections	Clinical diagnosis of disease (AD, PD, FTD, DLB)	Preclinical diagnosis of disease assisted by the use of biomarkers. Prodromal AD is a robust concept and has been already used in population-based studies. The definition of prodromal PD, DLB, and FTD is currently under development
Biomarker implementation models	Clinical-pathological model: clinical phenotypes are established, and then biomarkers are validated	Systems biology model: biomarkers are identified using larger, phenotype-agnostic studies of aging
Type of biomarkers used in population-based studies	Expensive PET imaging; CSF-based biomarkers perceived as invasive	Blood-based biomarkers, advanced radiotracer-free neuroimaging biomarkers with greater accessibility and low cost. A multimodal approach would add accuracy
Gold standard for disease diagnostic validity	Mainly clinical. In some cases, pathological confirmation	Deeply phenotyped large population-based aging cohorts will facilitate analyses anchored on outlier biological signals
Intervention strategies	Based on the concept of disease as a single biological entity. Amyloid reduction in AD, synuclein reduction in PD	Tailored on different disease phenotypes which share a common biological mechanism. Precision medicine approach