The MAS investigated rates and predictors of health and cognitive decline in older adults, specifically why normally functioning adults who show evidence of memory or cognitive decline either progress to dementia or improve. Participants aged 70 to 90 years were recruited through the electoral roll from two federal government areas of Sydney, Australia: Kingsford-Smith and Wentworth. a. Over 1000 participants completed baseline assessment, including a subgroup who underwent MRI scans and other sub-studies. Wave 1 took place from 2005 to 2007, and participants were followed up until Wave 7, which ended in 2020. Each wave included an annual telephone interview and a more detailed in-person assessment every two years.