In older age groups, measures such as BMI may not be the best methods to assess risk of dementia with increased body weight. Instead, other ways of measuring adiposity may be needed. Therefore, knowing when the change occurs will be important for informing the development of accurate protocols for calculating dementia risk in different age groups. These results will form a robust platform to develop new focused on predicting risk of cognitive decline not just in the 'old-old' but also in 'young-old' individuals. This is important for the development of intervention strategies focused on improvement and maintenance of cognitive function across different age groups.