Low dose aspirin therapy has been shown to reduce the risk of vascular events in a wide range of primary and secondary care settings, largely in middle-aged people. There is some evidence of its potential to reduce the rate of certain malignancies and the rate of intellectual decline in older individuals. However part of the benefit of aspirin may be offset by a variety of adverse effects and, in particular, the balance of risks and benefits of low dose aspirin has not been established in older people.

ASPREE was needed to resolve the current uncertainty regarding the effects of aspirin amongst older persons. ASPREE assessed the effects of low dose (100mg) daily aspirin versus placebo on death from any cause or incident dementia or persistent physical disability (1). Other clinically important outcomes relevant to aspirin’s efficacy and safety, including the prevention of cardiovascular events, cancer and cognitive decline, were also assessed. Outcome definitions are provided in the dedicated Study Endpoints section.

ASPREE screened and randomised 19,114 volunteers between the commencement of recruitment in March 2010 and the closure of recruitment in December 2014 (2). The screening process included two baseline visits (Visit 1 and Visit 2). The first visit involved initial lifestyle questions, cognitive screening and physical function screening followed by laboratory investigations and a medication compliance evaluation. The second visit included further assessments and confirmation of eligibility. In Australia, confirmation of eligibility required a clinical sign off by the participant’s usual General Practitioner (GP).

Following completion of both baseline visits, participants who satisfied all study entry criteria were randomly allocated to one of the two treatment groups and commenced the follow-up phase of the study. Participants were followed up for a median of 4.7 years and asked to attend the clinic for annual study visits. Phone contact with participants was attempted at three-monthly intervals.

Annual visits included subsequent lifestyle questions, wellbeing and recent medical history updates, hospital visitations and collection of concomitant medications. Cognitive screening was carried out on odd years; physical function screening alternately on even years. Haemoglobin was collected annually in both countries. A detailed description of the data collection schedule is provided in the dedicated Data Collection section.

During 2017, participants completed Milestone Visits that included all study assessments and an additional questionnaire about study medication, aspirin and over-the-counter medication use.

The ASPREE Clinical Trial ended in June 2017 when all participants ceased study medication. The final Milestone Visits were conducted following cessation of study medication up until January 31st 2018. This period is known as the Bridge. February 1st 2018 marked the beginning of the ASPREE-eXTension study. This is an observational cohort study of approximately 15,000 ASPREE participants who have agreed to be followed up for an additional five years (on average).

This information relates to the ASPREE Longitudinal Data Set, which includes data collected at Visits 1 and 2, Annual Visits 1, 2, 3, 4, 5, 6 and Milestone Visits during the ASPREE Clinical Trial (i.e. between March 2010 and June 2017). This data set does not include Bridge or ASPREE-XT data.

Please see here for a list of all ASPREE-related publications.


  1. McNeil JJ, Woods RL, Nelson MR, Reid CM, Kirpach B, Wolfe R, et al. Effect of Aspirin on Disability-free Survival in the Healthy Elderly. N Engl J Med. 2018 Sep;379(16):1499-1508. doi: 10.1056/NEJMoa1800722.

  2. McNeil JJ, Woods RL, Nelson MR, Murray AM, Reid CM, Kirpach B, et al. Baseline Characteristics of Participants in the ASPREE (ASPirin in Reducing Events in the Elderly) Study. J Gerontol A Biol Sci Med Sci. 2017 Oct;72(11):1586–93. doi:10.1093/gerona/glw342