The Pathology, Alzheimer’s and Related Dementias Study (PARDoS): Design and Characteristics of the First 4700+ Brazilian Participants

The Pathology, Alzheimer’s and Related Dementias Study (PARDoS) is a community-based clinical-pathologic study of aging and dementia in a large and diverse sample of Brazilians. Its long-term objective is to identify the environmental, genetic and molecular drivers of common conditions across the adult life span with an emphasis on Alzheimer’s Disease and Related Disorders clinical and neuropathologic traits. From July 31 ^st 2021 through February 11 ^th , 2025, more than 4,700 brains were collected at two autopsy centers and a major hospital system in the State of Sao Paulo, Brazil. Samples of other organs are also being collected. Their mean age was 71.7 years (range 18-106), 40.2% were Black/Mixed, 52.7% were male, their mean education was 6.3 years (range 0-25). Among those aged 65+, 32.9% had dementia and 18.8% had mild cognitive impairment. Neuropathologic data collection is ongoing. PARDoS fills several major gaps among clinical-pathologic studies given the large numbers and its unique age and education range, and socioeconomic status, race, sex, and other organ collection. Here we present the study design, demographic characteristics of the first 4,790 autopsied participants, and clinical characteristics of the first 4,283 with informant interviews.