Implications of health status in analysis of risk in older persons.

This article explores the hypothesis that health status in old age acts as a summary measure of health exposures over time and, as such, plays a central role as a determinant of survival and morbidity trajectories in old age. Evidence is presented for the utility of health status as a modifier of risk in other areas of gerontologic research, and an example of modification pertinent to the cholesterol-heart disease controversy in old age is presented. The potential of differential health status in old age to affect both risk factors and risk estimates in epidemiologic analyses may be an important principle as epidemiologists continue to development research to preserve and augment the quality of life in old age.