Life expectancy and health status of the aged.

There are several research issues which need further exploration if we are to better understand the implications of what appears to be increased levels of morbidity. Three general areas require additional research: the time of onset of chronic illness, the progression rate of illness, and the overlap and interaction between chronic and non-chronic conditions as well as multiple chronic conditions in a single individual. A major reason for the present uncertainty about morbidity is that information is unavailable regarding the incidence of chronic illness. However, incidence of chronic disease is difficult to measure unless there are either clear clinical indications or functional limitations. Work by survey researchers in defining initial reports of functional limitations associated with chronic illness would be very helpful. Furthermore, an understanding of incidence is necessary to further our understanding of the rate of progression of illness. The concept of a progression rate of illness makes sense only if we can have agreed upon measures of the onset of the illness. Both of these issues clearly require the use of longitudinal data. In fact any serious attempt to predict changes in health status over time as well as to relate changing patterns of mortality with changing patterns of morbidity will require a longitudinal data base. The difficulty in establishing a longitudinal data base is not only the time and expense of follow given set of individuals over a prolonged period of time, but also the problem of having a sample large enough to include individuals with specific chronic conditions of illness. One way to resolve the problem of sufficient sample size may be to do a combined survey which includes both a national probability sample of individuals as well as a sample of individuals with specific chronic diseases. Monitoring a group of individuals known to have specific chronic conditions would provide information about the progression and impact of the disease over time. Including a national probability sample of the entire population would provide information on the impact over time of changing health conditions for the entire population. While screening for specific conditions is an expensive procedure, it is likely to be far cheaper than including a sample size large enough to provide reliable estimates for specific conditions based on a national probability sample. Because the effects of postponed social security benefit eligibility will not be felt for many years, the opportunity for fruitful research is great. For now, we will summarize what we know from current research.