Introduction: Data on the population-based incidence of primary progressive aphasia (PPA), including all variants and Alzheimer's disease (AD) biomarker profiles, are scarce.

Methods: We conducted a 4-year, prospective, population-based study in the Salento region of Southern Italy, identifying incident PPA cases through a territory-wide surveillance network. Clinical diagnoses followed consensus criteria; AD pathology was defined by positive CSF or amyloid PET biomarkers.

Results: We identified 35 incident PPA cases, yielding an overall incidence of 1.14 (95% CI, 0.79-1.59) per 100,000 person-years. Incidence peaked in the early 60s for men and in the late 70s for women. The logopenic variant was most frequent and invariably associated with AD pathology. Approximately 20% of nonfluent and semantic cases, and the majority unclassified cases, also showed AD biomarkers.

Discussion: These findings provide real-world epidemiological evidence and underscore the need for systematic biomarker assessment in PPA to guide diagnosis, prognosis, and access to emerging therapies.