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Full-Text Articles in Physical Sciences and Mathematics
The Number Of Sick Persons In A Cohort, Paula Diehr
The Number Of Sick Persons In A Cohort, Paula Diehr
Paula Diehr
To see if the number of sick persons in a cohort was approximately constant over time, we calculated the number of sick persons in a “research” cohort of older adults followed for up to 14 years, and also in a synthetic birth cohort. Methods: In the research cohort, we calculated the actual number of persons in each health state over time, using eight different definitions of “sick”. For the birth cohort, we estimated the number of sick persons each year after birth. Results: The number of sick persons in the research cohort was approximately constant for 14 years, for all …
Software To Forecast The Global Burden Of Alzheimer's Disease, Ron Brookmeyer, Elizabeth Johnson, Kathryn Ziegler-Graham, H. Michael Arrighi
Software To Forecast The Global Burden Of Alzheimer's Disease, Ron Brookmeyer, Elizabeth Johnson, Kathryn Ziegler-Graham, H. Michael Arrighi
Ron Brookmeyer
Software was developed to forecast the global burden of Alzheimer’s disease and evaluate the potential impact of interventions that delay disease onset and progression. The output includes 50 year projections of Alzheimer's disease prevalence by stage of disease and region of the world. The methods are based on a stochastic multi-state model The software incorporates U.N. worldwide population forecasts and data from epidemiological studies on risks of Alzheimer’s disease. The user can also supply their own population projections, and modify input parameters for the model including the disease incidence rates, effects of interventions on disease onset and progression, and stages …
Modeling The Effect Of Alzheimer's Disease On Mortality, Elizabeth Johnson, Ron Brookmeyer, Kathryn Ziegler-Graham
Modeling The Effect Of Alzheimer's Disease On Mortality, Elizabeth Johnson, Ron Brookmeyer, Kathryn Ziegler-Graham
Ron Brookmeyer
Mortality rate ratios and the associated proportional hazards models have been used to summarize the effect of Alzheimer's disease on longevity. However, the mortality rate ratios vary by age and therefore do not provide a simple parsimonious summary of the effect of the disease on lifespan. Instead, we propose a new parameter that is defined by an additive multistate model. The proposed multistate model accounts for different stages of disease progression. The underlying assumption of the model is that the effect of disease on mortality is to add a constant amount to death rates once the disease progresses from an …