Yesterday, he shared his wisdom at a morning tea for 100 participants of a clinical trial that looks at the use of aspirin to prevent ill health in those aged over 70.

The study is the largest preventative health clinical trial in Australian history.

Half of the participants take a placebo and the other half a low dose of aspirin each day, and complete physical and mental testing once a year for five years with their GP.

The results will show whether the anti-inflammatory is effective in the prevention of strokes, heart attacks, dementia and cancers.

There are already 10,000 participants from Australia in the international study, which hopes to attract 12,000 people.

There are 1600 Tasmanian participants so far - 400 of which are from the Launceston area. Organisers are hoping for another 100 from Northern Tasmania by the end of the year.

University of Tasmania chairman of general practice, Professor Mark Nelson, is the chief investigator for Tasmania for the trial.

He credited participants with being altruistic and generous with their time.

"Tasmania is the number one recruitment site for the study in the world per capita," he said.

Professor Nelson said participants, their GPs and administration staff did not know whether participants were taking aspirin or a placebo, so the testing would not be biased.

Participant Roslyn Burr, 72, of Exeter, said she was "only too happy" to take part.

"Any little thing I can do to help prolong life, for future generations," she said.

• If you are over 70, in good health and would like to take part in the trial, please talk to your GP, who can refer you to the study.