The ASPREE (ASPirin in Reducing Events in the Elderly) project comprises: a) a multi-center, bi-national randomized controlled trial (RCT) of 19,114 older people in Australia and the US aimed at understanding the effects of low-dose aspirin on health outcomes, and b) a longitudinal cohort study of aging, with observational follow-up after completion of the RCT phase. With a rapidly aging global population, the primary objective of the ASPREE project is to discover methods to maintain health, quality of life, and independence as people age.

Inclusion Criteria: Participants in the ASPREE trial at baseline/enrolment were healthy adults aged ≥70 years (≥65 years for US participants), with no history of diagnosed cardiovascular disease, dementia, or major physical disabilities.

Exclusion Criteria: Individuals were excluded if they had a diagnosed history of cardiovascular disease (including myocardial infarction or stroke), dementia, major physical disability, or a condition that would require aspirin use for secondary prevention.

The ASPREE trial recruited 19,114 healthy older adults from Australia and the United States, most of them were with European ancestry. The ASPREE-XT follow-up study continues to monitor the cohort, focusing on the long-term health outcomes of these participants.

The primary focus of the ASPREE project is the prevention and long-term effects of low-dose aspirin on chronic diseases associated with aging, including cardiovascular disease, cancer, dementia, and physical disability and death. The ASPREE-XT study expands the scope to investigate broader factors that influence healthy aging, including genetic predispositions, lifestyle choices, and environment.

The initial hypothesis of the ASPREE trial was that daily low-dose aspirin would prolong disability-free survival in healthy older adults by reducing the risk of death, disability and dementia (with a composite primary outcome of disability-free survival). Secondary outcomes included cardiovascular disease, cancer and other related age-associated conditions. Following the trial’s conclusion, the ASPREE-XT study now seeks to understand whether aspirin confers longer-term benefits or risks in preventing chronic diseases, and is exploring other contributors and determinants of healthy aging.