The incidence of dementia in an Australian community population: the Sydney Older Persons Study.

OBJECTIVES: Limited Australian dementia incidence data are available. This study aimed to identify the incidence of dementia and its subtypes in an Australian community dwelling population. METHOD: A community dwelling sample of 647 subjects aged > or =75 years at recruitment were followed for a mean period of 3.2 years (range 2.6-4.5 years). The incidence of dementia (measured in person years at risk) was identified for different levels of severity of dementia, Alzheimer's disease and vascular dementia. RESULTS: Incidence figures were slightly higher than those previously reported. The incidence of dementia and of Alzheimer's disease increased with age but was not affected by gender. The incidence of vascular dementia was not affected by age. CONCLUSION: This study provides the largest body of data on the incidence of dementia in Australia, indicating a slightly higher incidence of dementia than previous reports. Further Australian data are required to confirm these findings.