Compression of Morbidity

As people live longer, some fear that they will spend additional years in poor health, disabled, and demented. In contrast, the compression of morbidity hypothesis (1980) posits that people can have both a longer life and a healthier old age. To do so, it is necessary to postpone the onset of morbidity (e.g., disability), through healthy preventive practices, more rapidly than death is postponed.

Figure 1 SOURCE: Author

Figure 1 depicts three future scenarios for morbidity and longevity. At present, disability begins to be detectable around age fifty-five in the average individual, and death occurs, on average, a bit after seventy-five years of age. Most disability occurs between these points, and the level of disability increases with time, as shown by the areas of the triangles. At some future time there could be (I) extended life expectancy but no change in the time of first disability. If that would be the case, each typical life would have more morbidity than at present. This scenario has been termed the "failure of success." Or there could be (II) extended life expectancy and postponed morbidity by about the same amount, so that everything happens the same but a bit later. Or there could be (III) more emphasis on postponing disease than on increasing life expectancy, thereby compressing morbidity between a later age of onset and a more slowly rising age at death. Morbidity and disability then would decrease for the typical person, and medical care costs might decline as well, providing relief for cost pressures on Medicare.

Data support the view that compression of morbidity is occurring, and can be made to occur more rapidly. First, life expectancy at advanced ages has plateaued rather than having increased markedly, as previously predicted. In the United States the life expectancy of women at age sixty-five, for example, has increased only 0.7 years since the 1980s. Second, epidemiologic studies have documented the ability to postpone the onset of disability by eight years through exercise, weight control, and not smoking. Over the period from 1982 to 1999, disability rates in the United States decreased at 2 percent per year while mortality rates declined only 1 percent per year. Third, randomized trials of health enhancement programs in seniors have shown reductions in health risks and medical care costs of 10 to 20 percent.

There are three stages in developing documentary evidence to support health policies directed at improving senior health: (1) a theoretical framework, as represented by the compression of morbidity hypothesis; (2) the epidemiologic data to establish proof of the concept; (3) randomized trials to establish the ability to intervene successfully. These data are now abundant.

The paradigm of a long, healthy life with a relatively rapid terminal decline represents an attainable ideal. Health policies must be directed at modifying those health risks which precede and cause morbidity if this ideal is to be approached for a population.