Nepal B, Brown L, Ranmuthugala G. Years of life lived with and without dementia in Australia, 2004-2006: a population health measure. Aust N Z J Public Health. 2008 Dec;32(6):565-8.

OBJECTIVE: To estimate the fraction of remaining life lived with and without dementia among Australian males and females at later life. METHOD: Analysis was performed by applying the life table technique that integrates mortality and morbidity statistics to derive a single population health indicator. Observed prevalence rates were used to calculate life expectancy with dementia. RESULTS: At the age of 65 years, males are expected to live an additional 18 years, of which 6% would be lived with dementia. Females surviving to 65 years, are likely to live a further 22 years, 9% of which is expected to be lived with dementia. At the age of 85 years, males live a further six years; one-sixth of this life spent with dementia. Females surviving to this age would live an additional seven years, with one-fourth of that life with dementia. The portion of life lived with dementia out of total remaining years of life increases with age at the rate of 20 to 30% every five years beyond the age of 65. CONCLUSION. The extension of life expectancy is associated with increased duration of life lived with dementia. As females live longer than males, they experience a greater impact of dementia.

Waite LM, Broe GA, Grayson DA, Creasey H. Preclinical syndromes predict dementia: the Sydney older persons study. J Neurol Neurosurg Psychiatry. 2001 Sep;71(3):296-302.

OBJECTIVES: To identify if preclinical syndromes for Alzheimer's disease, vascular dementia, and Parkinson's disease and related dementias exist. Identification of dementia at early or even preclinical stages has important implications for treatment. METHODS: A community dwelling sample of 647 subjects aged 75 and over at recruitment were followed up for a mean period of 3.19 years (range 2.61 to 4.51 years). Each subject was asked to participate in a medical assessment which included a standardised medical history examining both past and current health and medication usage; a neuropsychological battery (mini mental state examination, Reid memory test, verbal fluency, subsets of the Boston naming test and similarities, clock drawing and copied drawings) and physical examination. Preclinical syndromes for the three predominant dementias (Alzheimer's disease, vascular dementia and Parkinson's disease, and related dementias) and their combinations were defined using cognitive, motor, and vascular features. Their longitudinal outcome as defined by death and dementia incidence was examined. RESULTS: Preclinical syndromes affected 55.7% (n=299) of subjects. Preclinical syndromes showed a trend for an increased odds of death (odds ratio 1.72, p=0.056) and a significantly increased odds of developing dementia (odds ratio 4.81, p<0.001). Preclinical syndromes were highly sensitive, detecting 52 of 58 (89.7%) incident dementias. Two hundred and sixteen of 268 (80.6%) preclinical subjects did not show dementia over the 3 year period (positive predictive value 19.4%). Subjects defined as having a combination of cognitive, extrapyramidal, and vascular features were at greatest risk of progressing to dementia. CONCLUSIONS: Preclinical syndromes were sensitive and significant predictors of dementia. In view of their poor positive predictive value, the preclinical syndromes as defined in this study remain a research tool needing both definitional refinement and greater periods of observation. Multiple coexistent preclinical disorders resulted in a greater incidence of dementia, providing evidence for an additive role between multiple disorders.

Waite LM, Broe GA, Grayson DA, Creasey H. The incidence of dementia in an Australian community population: the Sydney Older Persons Study. Int J Geriatr Psychiatry. 2001 Jul;16(7):680-9.

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.

Nepal B, Ranmuthugala G, Brown L, Budge M. Modelling costs of dementia in Australia: evidence, gaps, and needs. Aust Health Rev. 2008 Aug;32(3):479-87.

With the rapid ageing of the Australian population, dementia has emerged as a major health and economic challenge. Consensus exists that the number of people with dementia will grow significantly because the prevalence is strongly correlated with age. However, there are substantial gaps in our understanding of the impacts on the dementia "epidemic" of changes in non-demographic risk factors and of our knowledge of the economic implications. Only a few prevalence-based studies have been conducted to examine the health economics of dementia in Australia. These studies have suggested that considerable resources are absorbed by dementia care, yet there is a lack of integrated models that simultaneously explore epidemiologic and economic perspectives incorporating the impact of preventive and early intervention initiatives. This study reviews the current evidence on the economic implications of dementia in Australia and approaches taken to project the future costs of dementia.