The role of longitudinal surveys among the elderly in predicting disability and longevity

The burden of human suffering and the costs of money, manpower and material for the treatment and maintaining of disabled and/or chronically ill--particularly ageing and old--people are increasing immensely. Primary prevention--if possible--is therefore urgently needed in this field of health and social care. Prospective longitudinal epidemiological research may provide an important tool to learn more and better about the causes and development of many processes of malfunctioning and the incidence of disabling conditions at higher ages. For several reasons not many major extensive surveys of this kind have been undertaken so far, although a few are now underway. A very brief overview is presented of some main follow-up surveys, primarily where predictors of disability and longevity are involved. Comparability is difficult, results are sometimes conflicting. Good objective health, high scores on certain intelligence and memory tests seem to be good predictors for longevity, good subjective health more or less. In a Dutch survey disabilities with respect to activities of daily life were more strongly related to survival time in women than in men. Some variables indicating the use of health care services correlated all negatively with survival. The complexity of variables to predict better at high age the risks of disabilities, and survival time, requires a.o. sophisticated longitudinal studies, upon the results of which to base an adequate policy response.