The Older Australian Twins Study, led by Perminder Sachdev and Julian Trollor of the Centre for Healthy Brain Ageing at the University of New South Wales, has been recruiting TRA twins (65 years old and older) for more than nine years and has made a substantial contribution to understanding brain ageing.
Brain ageing and brain diseases are determined by multiple genetic factors that interact with environmental influences. Since identical twins share 100 percent of their genes, whereas non-identical twins share half their genetic information, detailed comparisons of these two groups has the potential to discover new genes involved in cognitive decline or resilience.
The OATS aims to find out what influences memory and thinking as we age. It investigates environmental influences such as lifetime physical and mental activity, socioeconomic environment and nutrition. It also investigates how biological factors such as hypertension and antioxidant levels, interact with genes to influence brain ageing.
Since, over time, the expression of genes varies depending on different influences in the environment, by studying twins, OATS aims to determine which influences on the ageing process are genetic, which are environmental, and how the two interact.
In 2015 a new OATS sub-study was established to investigate the deposition of amyloid plaques in the brain using positron emission tomography (PET) scans. Amyloid plaques are thought to predict memory decline with age. Performing these scans on twins will help the researchers establish how amyloid plaques relate to performance in memory and thinking ability.
The researchers also aim to determine if there is a genetic component, and if there are any potentially modifiable environmental factors that may be contributing to the development of the plaques.