Delaying dementia and nursing home placement: the Dubbo study of elderly Australians over a 14-year follow-up.

In order to capture the "longevity dividend," modifiable risk factors for a diagnosis of dementia and nursing home placement were examined in a longitudinal study of an elderly cohort living in Dubbo, New South Wales, Australia. One thousand two-hundred thirty-three men and 1572 women 60 years and older living in the community were examined in 1988 and followed to 2002 for diagnosis of dementia and nursing home placement. There were 244 (8.7%) nursing home placements and 44% of these placements were primarily due to dementia, but dementia was a secondary diagnosis in another 20% of cases. In a proportional hazards model for dementia, any intake of alcohol predicted a 34% lower risk, and daily gardening a 36% lower risk. Daily walking predicted a 38% lower risk of dementia in men, but there was no significant prediction in women. The lowest tertile of peak expiratory flow predicted an 84% higher risk of dementia, the upper tertile of depression score predicted a 50% higher risk. The Cox proportional hazards model for nursing home placement, showed placement increased significantly with age, urinary incontinence, impaired peak expiratory flow, physical disability, and depression. The hazard of placement was significantly reduced by alcohol intake and female gender. Socioeconomic factors were not significant. Similar risk factors for dementia and nursing home placement indicate that the continuation of moderate alcohol intake, the maintenance of physical activity, especially daily gardening, and improvement of respiratory function, and the treatment of depression are recommended targets for interventions to delay or prevent major negative late-life experiences.