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The number of sick persons in a cohort
Research on Aging (2007)
  • Paula Diehr, University of Washington
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 definitions of “sick”. The number sick in the birth cohort was approximately constant from ages 55-80, and then declined. Conclusions: The relative excess of sick persons in later life is caused by a decline in the number of healthy persons rather than an increase in the number who are sick. The number of current Medicare enrollees who are sick may be approximately constant for 14 years. These insights may help in planning for the aging population.
  • self-rated health,
  • equiligrium,
  • health state,
  • projection,
  • aging,
  • medicare
Publication Date
November, 2007
Citation Information
Paula Diehr. "The number of sick persons in a cohort" Research on Aging Vol. 29 Iss. 6 (2007)
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