Unlike most of the items in the cost of living, the costs of illness vary greatly from family to family and from person to person. In any given month or year, serious and extremely costly illnesses strike only a relatively small proportion of the population, but their costs can be catastrophic, especially in this era of astronomical hospital charges. Even the less severe illnesses that result in a few days’ loss of work are unevenly distributed. Hence the pooling of risks through insurance is particularly appropriate in meeting the costs of illness, and, as we have noted in Chapter 3, the mutual aid funds and friendly societies that were formed in the nineteenth century were especially concerned with meeting the costs of short-term sickness. They tended to provide modest cash benefits for loss of work and a portion of medical expenses.

Not only does the incidence of illness vary among persons generally, but also certain groups in the population are particularly prone to experience illness, as the data in Table 10.1 show. Women are more likely to have restricted-activity days than men (partly due to pregnancy and childbirth), blacks than whites (partly, at least, because they are more likely to be employed in heavy labor), and persons aged 65 and older than those under age 65 by a very large margin. Particularly striking, also, is the pronounced inverse relationship to income. The high average days of illness in the two lower income groups reflect to some extent the interdependence of ill health and low earnings, and also the large proportion of elderly people in the low-income population.